SPEAKER TESTING WITH DIY ACCELEROMETER

Transcription

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CONTENTS
volume 42
number 6 June 2011
FEATURES
DEPARTMENTS
ACCELEROMETER TESTING OF
LOUDSPEAKER DRIVERS
PRODUCT REVIEW
Add this speaker measurement system to your test
Reviewed by Gary Galo...................................... 24
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Testing audio/video performance with this LFE box.
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speakers
By George Danavaras
Accelerometer Testing of
Loudspeaker Drivers
Test your speakers' performance with this do-it-yourself measurement system.
I
n this article, I will describe the
design and operation of a system
consisting of the ACH-01 accelerometer and a preamplifier with
an integrated analog signal processor
(Photo 1). With this system, it will be
possible to measure at the low frequencies the acceleration, the velocity, and
the excursion of a loudspeaker cone.
Also the panel vibrations of a loudspeaker cabinet will be very easily obtained.
The ACH-01-03
accelerometer
The ACH-01 (Photo 2) manufactured
by the Measurement Specialties (www.
meas-spec.com) is an inexpensive, general-purpose, linear single axis accelerometer with a very wideband response
(specified within 3dB from 2Hz to
20kHz) and internally buffered for low
output impedance. It can measure up to
±150g and has a high resonant frequency
at 35kHz. The output voltage of the accelerometer is directly analogous to the
acceleration that it measures. The ACH-
PHOTO 1: The Accelerometer amplifier.
6
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PHOTO 2: The ACH-01 accelerometer.
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FIGURE 1: Sine wave amplitude
definitions.
01-03 version of the accelerometer is
housed in a small, rugged, flat package
and is supplied with a shielded cable.
Simple harmonic motion
theory
Before I proceed to the description of
the preamplifier, I think that it will be
very helpful to refresh your knowledge
about the theory of the simple harmonic
motion. So here is a brief description.
Suppose that you have an ideal loudspeaker cone that is driven with a sinusoidal signal as shown in Fig. 1. The
instantaneous value of the displacement
(=excursion) of the cone can be written
in the following form as a function of
time t:
x(t) = Xpeak × sin(ω × t)
Where Xpeak is the maximum value
of the displacement and ω = 2 × p × ƒ is
the angular frequency.
The velocity of the piston as a function of time is the first derivative of the
displacement and is given by:
v(t) = dx(t) = ω × Xpeak × cos(ω × t)
dt
Similarly, the acceleration is the first
derivative of the velocity (or the second
FIGURE 2: The op amp integrator circuit.
derivative of the displacement) and is
given by:
a(t) = dv(t) = –ω2 × Xpeak × sin(ω × t)
dt
From the above relations you see that
the peak velocity of the cone is:
Vpeak = ω × Xpeak
And the peak acceleration is:
Apeak = –ω × Vpeak = –ω2 × Xpeak.
The RMS values of the above are defined as follows: (see also Fig. 1)
For the displacement:
Xrms = Xpeak
√2
For the velocity:
Vrms = ω × Xrms and
For the acceleration:
Arms = ω × Vrms = –ω2 × Xrms
For example, assume that you have
a loudspeaker cone, which is driven by
a sinusoidal signal with a frequency of
20Hz and the peak-to-peak displacement of the cone is 10mm. Then the
peak value of the displacement is 5mm
FIGURE 3: The block diagram of the Accelerometer preamplifier.
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and the RMS value of the displacement
is: Xrms = 3.53mm.
The RMS value of the velocity is
m and the RMS value of
Vrms = 0.444 sec
the acceleration is Arms = 55.83 m 2
sec
Now what you need for your design is
to apply the reverse procedure and compute the displacement and the velocity
of the simple harmonic motion when
the acceleration is known. Suppose that
the acceleration of a piston is a(t) as a
function of time t.
Then by reversing the above, the velocity can be calculated by the following:
v(t) = ∫a(t)dt
And similarly, the displacement can
be calculated by the following:
x(t) = ∫v(t)dt
The above means that we can use an
integrator circuit to compute the velocity from the acceleration and then one
more integrator circuit to compute the
displacement from the velocity. This is
exactly how the Analog processor of the
accelerometer preamplifier operates.
The Integrator Circuit
The integrator forms the basis of the accelerometer preamplifier processor. Two
integrator circuits that are based on an
op amp are shown in Fig. 2. The left
is an ideal integrator and the right is a
more practical circuit. The main component of these circuits is the operational
amplifier, configured in such a way that
its output voltage is proportional to the
integral of its input voltage.
The output of the circuit is given by
Vout = 1 ∫Vin × dt
RC
The resistor Rf reduces the gain of
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5346 D
the circuit at the very low frequencies
(theoretically the gain of the ideal integrator at DC is infinite) because otherwise the output of the op amp will
saturate after some time.
The integrator can also be seen as
an active low-pass filter with a very low
cutoff frequency.
The Electronic Diagram
The preamplifier is based on the block
diagram of Fig. 3. The first stage buffers
the signal from the ACH accelerometer
and can provide a gain of 10 or 20dB
when the output of the accelerometer is
very low. The next stage is a high-pass
filter with a user selectable cutoff frequency. An integrator follows and has
as output the velocity of the input while
the next integrator has as output the excursion (or displacement).
The complete electronic diagram of
the voltmeter is shown in Fig. 4. At the
input of the circuit, there is a threepin connector for the connection of the
ACH accelerometer to the amplifier.
One pin is used for the voltage supply
to the Accelerometer, the second is the
output of the accelerometer, and the
third is the Ground pin.
The voltage that supplies the accelerometer should have a very low ripple and
for this reason a RC low pass filter consisting of the resistor 24kΩ and the capacitor
470µF filters additionally the voltage.
Transistor Q1 with the components
R1, R2 and Led1 bias the internal FET
of the Accelerometer with a constant current of 20µA. The jumper JP4 is used to
connect or to disconnect the bias circuit to
the input pins. This is helpful for the calibration of the circuit, as you will see later.
The op amp IC1A and the components around it buffer the output of
the accelerometer and provide with the
switch S1 a selectable gain of 0 or 10 or
20dB. It is very important that for the
measurement of the velocity and the
excursion the S1 switch should be set to
the 0dB gain (indicated as Normal position on the front panel).
The components C13, C15, C16, and
R24 with the op amp IC1B form a firstorder high-pass filter and the switch S2
selects the cutoff frequency between 1,
10, or 50Hz. The op amp IC2A with
R3, R5, and C11 form the first integra10
FIGURE 4: The electronic diagram of the Accelerometer preamplifier.
FIGURE 5: The PCB layout of the Accelerometer preamplifier.
audioXpress 6/11
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Dana3278.indd 11
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PHOTO 3: The PCB of the accelerometer amplifier.
FIGURE 6: The front panel of the Accelerometer preamplifier.
tor, which gives at its output the velocity.
The op amp IC2B with R6, R7, and
C12 form the second integrator that
gives as its output the excursion (or displacement) of the input signal. Trimmer
R26 calibrates the output signal for the
acceleration, trimmer R22 calibrates the
output signal for the velocity and trimmer R23 calibrates the output signal for
the excursion. Switch S3 selects the type
of the signal that will be connected to
the output of the preamplifier.
For the supply of the preamplifier I
used an external power supply pack with
a nominal output voltage of 15V DC
and a current capability of 300mA. This
gave an actual output voltage of about
16.4V DC but with a very low ripple
because the total current consumption
of the preamplifier is only 14mA. This is
very important for the good operation of
the circuit.
The PCB
The construction of the preamplifier is complicated so I designed a PCB
using the Demo version of the Eagle
Layout editor. You can download this
demo version of the program free from
Cadsoft (www.cadsoftusa.com). The
demo version is fully operational except
12
PHOTO 4: The placement of R11 and C17 on the bottom of the PCB.
a limitation on the maximum dimensions of the PCB, which was not a problem for this project.
The placement of the components on
the PCB is shown in Fig. 5.
All the components are placed on the
topside of the PCB except the resistor R11 (24kΩ) and the capacitor C17
(470μF) that are mounted on the bottom side of the PCB. Before the placement of R11 the PCB track that connects the power supply to the pin 3 of
the Input connector should be cut. See
Photo 4 for the details.
The three rotary switches S1, S2, and
S3 are placed directly on the PCB to
facilitate the construction of the meter.
In Fig. 6, the diagram of the front
plate that I used for the meter is
audioXpress 6/11
Dana3278.indd 12
shown. I printed this diagram to a
self-adhesive transparent paper, which
then was put on the front panel of the
metallic box of the meter. This gave
a very attractive look for the meter as
shown in Photo 1.
I also used the same diagram, printed on normal paper, as a guide for the
opening of the holes for the rotary
switches, the output connector, and the
power supply connector.
Calibration of the
Amplifier
The sensitivity S of the ACH-01 accelerometer is given in mV/g where g is the
m (the typical value
Earth’s Gravity in sec
2
m
is g=9.81sec 2 ).
Suppose that E (in mV RMS) is the
4/27/2011 2:40:10 PM
PHOTO 5: The setup for checking the accuracy of the system.
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the Puresonic Spring Spade Terminal.
The fork in the spade is split to allow
them to be compressed when the
binding post is tightened. The spring
pushes back on the post and will not
loosen, assuring a very tight
connection.
PHOTO 6: Closeup of setup.
actual output voltage of the accelerometer then the acceleration Arms that is
measured by the accelerometer is given
by the following:
Arms = g × E m 2
S
sec
If you know the acceleration and the
frequency (ω = 2 × p × ƒ), the velocity is
computed by:
rms m
Vrms = Aω
sec
And the displacement is computed
by: xrms = Aωrms2 in meters. Now, for the
calibration of the amplifier we will make
some calculations based on the above
formulas.
The ACH-01 is provided calibrated
from the factory and the one that I used
had a sensitivity of S = 9.1mV/g.
If you suppose that the output of the
accelerometer is E = 110mVrms at the
frequency of 40Hz then you have:
The acceleration is:
The Puresonic spades are also made
from Tellurium Copper and are a
perfect match to the Propeller Posts.
The spades are available in either
Rhodium or 24 carat gold plating.
Arms = 9.81 × 110 m2= 118.58 m 2
sec
9.1 sec
audioXpress June 2011
Dana3278.indd 13
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FIGURE 7: Accelerations measurements.
Table 1: Comparison between digital caliper indication
and accelerometer amplifier measurements.
Digital Caliper Indication 5 mm
Positive peak Negative peak Positive peak Negative peak
Positive peak Negative peak Frequency
cone
cone
Frequency
cone
cone
Frequency
cone
cone
excursion
excursion
excursion
excursion
excursion
excursion
(HZ)
(mm)
(mm)
(HZ)
(mm)
(mm)
(HZ)
(mm)
(mm)
15
4.9
5.14
15
10.1
10.41
15
14.7
15.05
20
5.05
5.24
20
10.27
10.9
20
14.7
15.6
The velocity is:
Vrms = Arms m = 118.58 = 0.472 m
sec
ω sec 251.32
And the excursion is:
Xrms = Arms
= 118.58 = 0.1.877mm
ω2 63165.46
Now you can proceed with the calibration of the amplifier. For this, I used
a low distortion audio frequency generator, a digital frequency meter, and
my true RMS digital Voltmeter (audio
Xpress, July 2009, p. 12).
I set the frequency of the audio generator at exactly 40.00Hz and the level
at 110.0mV RMS. I removed the jumper
JP4 (to disconnect the bias circuit) and
connected the generator to the input of
the amplifier (pin 2 for the + and pin 3
for the – of the input connector).
I connected the RMS Voltmeter to
the output of the preamplifier and I set
the switch S3 to the acceleration and I
adjusted the trimmer R26 so that the
Voltmeter indication was 118.6mV RMS
m ).
(which means that 1mV RMS = 1 sec
2
Then I set the switch S3 to the Veloc14
ity position and I adjusted the trimmer
R22 so that the RMS Voltmeter indication was 47.2mV RMS (which means
m ).
that 1mV RMS = 0.01 sec
Finally I set the switch S3 to the Excursion position and adjusted the trimmer R23 so that the RMS Voltmeter
indication was 187.7mV RMS (which
means that 1mV RMS = 0.01mm). This
completes the calibration of the preamplifier.
Checking the System
After the calibration of the preamplifier,
I was thinking of a method to check the
measurement accuracy of the accelerometer and the calibrated preamplifier.
Photo 5 shows the setup that I used:
A Peerless 830500, which is a 12″
loudspeaker.
A power amplifier for driving the
loudspeaker.
A Fluke 289 True RMS multimeter
which can measure the peak (positive
and negative) values of a signal and
A digital caliper.
The demo version of the ARTA software (http://www.fesb.hr/~mateljan/arta/).
audioXpress 6/11
I mounted the accelerometer on the
middle of the loudspeaker cone (Photo
6) using double-sided tape. The digital
caliper was firmly mounted perpendicular with the cone of the loudspeaker
using thick aluminum bars. The depth
probe of the caliper was moved down
until it touched the surface of the accelerometer and the indication of the
digital caliper was set to zero (0.00mm).
Then the depth probe was moved
up some millimeters to allow the loudspeaker cone to move and I increased
very slowly the voltage level to the loudspeaker until I just heard the accelerometer hit the edge of the depth probe.
This means that the positive peak excursion of the loudspeaker cone was equal
to the indication of the digital caliper.
The measurements were performed
for two different frequencies (15 and
20Hz) and for three different peak cone
excursions (5mm, 10mm, and 15mm).
The results are indicated in Table 1.
For the 5mm excursion at 15Hz
the indication of the preamplifier was
4.9mm for the positive excursion and
5.14 for the negative excursion.
At 20Hz the indication of the preamplifier was 5.05mm for the positive excursion and 5.24 for the negative excursion.
The above results prove that the
measurements of the accelerometer are
very close to the indication of the digital caliper.
Some Interesting
Measurements
I used the accelerometer and the preamplifier to perform some measurements on
my current four-way loudspeaker system.
Each channel consists of a separate closed
box subwoofer with an Infinity 12″ speak-
er which operates up to 62Hz, two Peerless 830452 woofers as open baffle dipoles
that operate from 62 to 162Hz, a SEAS
ER18 mid/woofer on an open baffle dipole that operates from 162 to 2.2kHz
and a SEAS H1499 DXT tweeter.
The measurements that I performed
are shown in Figs. 7-10. For the measurements of Figs. 7 and 8, the loudspeaker was driven with pink noise and
the accelerometer was mounted in the
center of the loudspeaker’s cones. I used
the acceleration and the excursion output of the preamplifier.
In Fig. 7, I measured the acceleration of the Peerless cone, the acceleration of the SEAS ER18 cone, and the
acceleration of the front panel, which
supports the loudspeaker units to examine their relative amplitudes. The drive
voltage to the loudspeaker was the same
in all measurements. It seems from this
measurement that from the 350Hz to
500Hz the level of the front panel is
about –30dB down from the level of the
loudspeaker cone. This indicates that
more damping of the front panel is necessary for this range.
In Fig. 8, I kept the same drive voltage to the loudspeaker and measured the
excursion of the Peerless cone and the
excursion of the SEAS ER18 cone to
examine their relative amplitudes. For the
measurements of Fig. 9, I put the accelerometer on the center of the cone of the
Peerless woofer and kept the drive voltage
to the loudspeaker constant at 20V RMS.
I measured the distortion of the acceleration output signal at different frequencies
and then the positive and negative peak
excursion of the loudspeaker cone.
For the measurements of Fig. 10, I
increased the drive voltage to the loudspeaker until the distortion of the cone
acceleration output voltage was about
10%. Then I measured the drive voltage
to the loudspeaker and the peak-to-peak
excursion of the loudspeaker cone.
Unfortunately my test amplifier had
a maximum output voltage of about
22V RMS, so it was not possible to
continue the measurements in higher
frequencies that demand much more
output voltage drive.
Conclusion
This is a very useful test and measurement
system. It measures the acceleration, the
velocity, and the excursion of a loudspeaker cone or a loudspeaker panel with good
accuracy. It is easy to use and the cost to
build is very reasonable. If you don’t have
such equipment in your lab, here is a good
opportunity to build one. aX
FIGURE 8: Cone excursion measurements.
FIGURE 9: Peerless 830452 measurements at 20V RMS.
FIGURE 10: Peerless 830452 cone excursion and voltage drive for 10% cone acceleration distortion.
Parts list of the Accelerometer preamplifier
Part
Value C1, C11
1µ, MKT
C2, C3, C9, C17
470µ/25V, electrolytic
C4
22µ/25V bipolar
C5, C6
68n
C7, C14
100p
C8, C10
6.8µ/25V, electrolytic
C12
100n
C13
2.2µF/MKT
C15
33n
C16
150n
D1
1N4007
IC1, IC2
AD712
LED1
Green LED 5MM
Q1
BC548B
R1
4k7
R2
68k
R3
9.1k
R4
220k
R5
150k
R6, R17
11k
R7
620k
R8, R9
27
R10
220
R11
24k
R12
1k5
R13
360
R14
3k3
R15, R16, R20
10k
R18
9k1
R19
5k1
R21, R24
100k
R22, R23, R26
2k, Multi-turn trimmer
S1, S2, S3
Switch CK102X06
Dana3278.indd 15
15
4/27/2011 2:40:35 PM
s o l i d s t at e
By Mike Danbury
Low Frequency Effects Mixer
Enhance your movie-viewing experience with this LFE channel mixer.
W
ith the advent of the home
theater experience and surround sound, many people
find themselves dealing with
the nuisance of locating a subwoofer
in a convenient spot in their AV room.
Longstanding audiophiles oftentimes
are in possession of speakers which already are capable of very good bass, but
may have no way of routing the Low
Frequency Effects (LFE) channel on
the output of their players to the speakers. Traditionally, the LFE channel is
intended for driving a subwoofer system,
but in a home environment there’s technically no reason why it can’t be mixed
in with the left and right channels to
present the bass sound, thus eliminating
the need for the extra subwoofer.
FIGURE 1: Power supply options.
FIGURE 2: LFE mixer.
16
audioXpress 6/11
DanburyStaggs.indd 16
4/27/2011 2:21:41 PM
Originally approached by a friend
who found himself in this situation, I
set out to design a simple mixer that
would blend the LFE channel in with
the L and R front channels. One of his
requests was also to include low-pass
filters on the three channels to help suppress digital artifacts. I was somewhat
dubious about the low-pass filters and
their effect on the sound, but complied
without comment.
The construction process started with
an e-mailed schematic to the friend followed by parts procurement on his part.
Having had good success with using
rechargeable batteries in his preamp, he
elected to run the mixer module off batteries also. He chose to have the batteries external in the prototype, connected
via a Cinch Jones connector, thus allowing them to be plugged into the charger
in his preamp when not in use.
FIGURE 3: L & R low-pass filter response, 1K source.
FIGURE 4: L & R low-pass filter response, expanded, 1K source.
FIGURE 5: L & R low-pass filter response, 50Ω source.
CIRCUIT DESIGN
The power supply schematic (Fig. 1) offers two power options for possible use
in the mixer: AC or batteries. The actual
circuit is constructed on a simple pointto-point proto board (Photo 1), which is
mounted in a cast aluminum box. Five
RCA jacks are used for interconnecting
purposes, and an umbilical for connecting the batteries, which are two 9.6V
NiMH types rated for 2.0 Amp-hours.
Figure 2 is the schematic for the
mixer itself, based around three
NJM4580 dual op amps. The L and R
input low-pass filters, IC1A and IC2A,
are designed to work with source impedances from 0Ω to 2k. Figures 3-6 highlight the frequency response for 50Ω, 1k,
and 2k. Maximum deviation occurs at
2k with a -.1dB drop at 20kHz.
The LFE input connects to a 10K
linear potentiometer for level adjustment, and is buffered by IC3A, which
is configured to have a gain of two via
resistors R303 and R304. As such, the
FIGURE 6: L & R low-pass filter response, 2K source.
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• Articles
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Toll Free: (866) 371-0512 Fax: (516) 883-1077
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PHOTO 1: The mixer box.
17
4/27/2011 2:21:45 PM
50% wipe point on the pot roughly correlates to the 0dB point for the LFE information. This allows for an adjustment
range from essentially nothing to +6dB.
Mixing is accomplished at IC1B and
IC2B via R104, R105, R204, and R205.
Overall unity gain is preserved by the
selection of R106, R107, R206, and
R207. Input filters IC1A and IC2A use
non-standard values of capacitors. To
obtain the values specified in the schematic, smaller capacitors were paralleled
and then measured with a meter.
APPRAISAL
Initial sonic impressions of the mixer
Parts List:
Resistors
R101, 201
R102, 202, 305, 306
R103,203,302
R104, 105, 106, 204,
205, 206, 303, 304
R107, 207
R108, 208
R301
R401, 402
R403
Capacitors
C101, 201
C102, 202
C103, 203
C104, 204
C301
C302
C303
C304
C401
C402, 403, 404, 405
C406, 407
C408, 409, 412, 413, 416, 417
C410, 411, 414, 415, 418, 419
1K, RN60
2K, RN60
47.5K,RN60
10K, RN60
8.21K, RN60
51.1, RN60
3.92K, RN60
3K, RN60
2.2K, RN65
or similar
1.9nF, see text
880pF, see text
33pF
5pF
3.9nF
8.2nF
4.7nF
2.2nF
.01µF, 250V,
“X” across the
line type
2,200µF, 25V
.1µF, 50V
.01µF, 50V
100µF, 25V
were quite good. Not only did it mix
in the LFE signal as intended, but it
seemed to improve the sound in general.
This held true for all types of discs that
were tried, including regular CDs. Why
this should occur is open for speculation,
though it’s possibly related to high-frequency digital artifact suppression in the
audio path due to the low-pass filters.
To conclude, I was surprised by how
much enjoyment having the LFE channel
information mixed in added to the movie-watching experience. That, combined
with the large 52-inch screen and Blu-ray
player, very much gave the illusion that I
was almost in a movie theater. aX
Semiconductors
IC1, IC2, IC3
D1 – D6
D7
Inductors
L1 – L4
Transformer
T1
Misc
F1
S1
P301
RCA Jacks, (5)
Proto board
Power Cord,
Hook Up Wire
Chassis
Hardware
NJM4580
1N4004,
or similar
Pilot Light,
LED,
User’s Choice
330µH, Mouser
580-18334C,
or similar.
www.mouser.com
Avel Y236101,
or similar. www.
avellindberg.com
Fuse, 2A, holder
Power Switch,
user’s choice
10K,
Potentiometer,
Linear
LFE SUMMER
By D. E. Staggs
Ichannel from my Sony Blu-ray player with the front left and right
recently mentioned to Mike the possibility of summing the LFE
channels. The speakers I use there are very much full-range, so it seemed
like a good experiment, and if successful, would save the expense of a
subwoofer. Also, the LFE would come from two sources rather than one.
Hours after the conversation, a schematic appeared in my e-mail with all
the details worked out.
After collecting the components and parts I didn’t already have, I assem18
audioXpress 6/11
4/27/2011 2:21:47 PM
bled the circuit on a pad-per-hole prototyping board,
using tinned copper wire and Teflon insulation to provide the function of “foil traces.” It took a little longer to
install everything in a cast box. The system checked out
OK, so I cabled it in behind the Blu-ray player.
OPERATION
It took only a couple of action movies to set the LFE
level. The mix is very nice, too, in that the bass follows
the preamp volume control; no further adjustments
are needed. This experiment turned into a successfully
completed project simply by using the potentiometer.
But on further listening, it became obvious that the
sonic quality of the Blu-ray player had been catapulted
from mid-fi to obviously surpassing that of my heavily
modified DVD player. Both movie and CD audio experienced a surprising improvement in clarity and realism.
The color rendering and image sharpness visible
from both DVD and Blu-ray movies also made a surprising leap in performance. Now the video surpasses
anything I have seen in retail demonstrations. On one
of his infrequent visits, Mike readily heard and saw
these improvements, too.
UNEXPECTED RESULTS
Would this little box perform the same cleanup on the
signals coming from my old DVD player? I patched it
in and played some favorite CDs and DVDs to find
out. The highly modified DVD player experienced
the same type and level of improvements in audio and
video as the Blu-ray spinner. Therefore, I compared the
sound and picture quality of the drum piece in Animusic II (www.animusic.com).
The audible consequences of all my power supply and
signal capacitor modifications in the DVD player became more evident, and it audibly nosed out the Blu-ray
player, but not by much. The most apparent differences
were in the ease of details at the frequency extremes,
particularly in the very low registers, where large, highquality capacitors always help. A check with Digital
Video Essentials (www.videoessentials.com) showed that
the DVD player does not add the LFE channel to the L
and R channels (the only analog audio it sends out).
The S-video image from the DVD player sharpened
up, became more detailed, and the colors improved
significantly. The same disc on the Blu-ray player looks
somewhat sharper, but both now make beautiful images. Color is very similar between machines.
In this system, the Samsung HDTV must interpolate
the lines up to 1080 from the DVD player, while the Bluray player does it before sending the data out via HDMI
cable.
The main result otherwise is that I now need to
build a new LFE summer for the Blu-ray player with
five channels, because I am nearing completion of a
pair of surround speakers. ■
19
4/27/2011 2:21:49 PM
sound solutions
By Dennis Hoffman
Electronics Grounding
To clear up any confusion you may have, here’s a handy primer on grounding.
Chassis Ground
or Earth Ground
FIGURE 1: Signal
ground symbol.
D
FIGURE 2: Earth
ground symbol.
ennis Hoffman offers this short
survey of one of the worst problems in electronics: Grounding.
Like the proverbial Paddy’s Flea,
incorrect grounds are very hard to find.
They cause noise that no one wants and
finding them is a harrowing pastime. No
matter how many articles are written on
this topic, there will always be more—even
on the last day of the world’s end. Read
Mr. Hoffman and be enlightened.
—ETD.
Electronics Signal Ground
or Circuit Common
Signal ground is the current return to the
power supply. Current leaves the power
supply, passes through the various electronic components, and then returns to
the supply.
The typical symbol for signal ground
is shown in Fig. 1.
Chassis ground is an electrical safety
requirement to prevent an electrical
or electronic device’s chassis from delivering an electrical shock. A long
copper rod is driven into the ground
outside of the building, and a wire
connects the metal chassis to the rod
which is at the approximate 0 volt potential of the earth.
The symbol for earth ground is
shown in Fig. 2.
Two Details About Ground
1. Ground is not exactly 0V.
2. Two physically different ground
points will not be at the same voltage
potential.
Ground Loop
1. By definition, current will flow in
an electrical conductor connected to a
difference in voltage potential between
two points.
2. Because two physically different
ground points are not at the same potential, current will flow through an
electrical conductor connected between
those two points. This is a Ground Loop.
3. Notice this current flowing be-
FIGURE 3: Connecting two separate systems: single-ended/
unbalanced.
20
audioXpress 6/11
Hoffman3297.indd 20
tween these two different ground points
is not related to or correlated to any
electronic data or message signal. This is
noise or garbage that will interfere and
distort any information contained in the
electronic system.
Note: while “noise” can be added to
systems on occasion, it is specifically
controlled and the exact quantity is regulated.
Example
Given: A ground loop producing 610µV
of ground noise; a very small quantity.
A typical SLAC SAM is a 16-bit A/D
converter with a 0 to 10V input.
The smallest voltage it can resolve is:
= 10V/16 exp 2
= 10V/65,536
= 152.5µV
Note that the ground loop noise is
four times greater than the actual data,
so that A/D converter loses two bits of
resolution, and it is now a 14-bit converter.
Connecting Two Systems
with Single-Ended/Unbalanced Amplifiers
1. In Fig. 3 the two grounds exist at
different potentials, so some current will
FIGURE 4: Complete single-ended/unbalanced schematic.
4/27/2011 2:52:08 PM
flow between the grounds.
2. This ground current has nothing to
do with any signals being amplified, and
it is noise decreasing the accuracy of the
system. See complete schematic in Fig. 4.
with Transformers
1. There is no ground connection, so
there can be no Ground Loop.
2. Common-mode rejection of RF
interference.
3. Signals are AC coupled, so of limited use for circuits with DC data such
as accelerator focus and bend magnets
(see Fig. 5).
with Differential Amplifiers (Fig. 6)
1. There is no ground connection, so
there can be no Ground Loop.
2. Common-mode rejection of RF
interference (see Fig. 7).
3. Signals are DC coupled, so this is
the perfect solution for circuits with DC
data.
This article is from a class that Dennis Hoffman teaches at the SLAC National Accelerator Laboratory (Menlo
Park, Calif.). aX
7052PH
Phantom Powered
Measurement Mic System
NOW 4Hz to 25+kHz
<18dBA >135dBSPL
IEC61094-4
Compliant
1dB/div
30 kHz
FIGURE 5: Connecting two separate systems: transformer coupled.
FIGURE 6: Connecting two separate systems: differential/balanced.
Titanium
Diaphragm
FIGURE 7: Common-mode rejection.
www.acopacific.com
Hoffman3297.indd 21
21
4/27/2011 2:52:13 PM
phono
By Patrick M. Brunner
Make Your Turntable
Sound Marbelous!
Vinyl lives in this author’s audio system, thanks to a simple
solution to a weighty concern.
PHOTO 1: Unmodified base.
PHOTO 2: Unmodified deck.
22
audioXpress 6/11
Brunner611.indd 22
I
recently decided to go “retro” and try
some of my old LPs. I found that my
old turntable, a quartz-locked JVC
QL-A2, needed some minor repairs.
It was near top of the line, far better than
average, about 30 years ago. I replaced
the power supply electrolytic capacitors,
changed the dim red strobe LEDs to
bright new blue ones (adding a resistor to
reduce the brightness), and cleaned and
adjusted the pots that control the speed
locking, and all was well. Well, almost.
The first LP sounded fine until I
turned the volume up a bit and acoustic
feedback caused the system to howl very
badly. The problem was that my system
now has greatly improved bass response
as compared to three decades ago. How
to stop the feedback?
My first thought was to glue lead
sheeting inside the turntable base, until
I found that it would cost over $150
for a roll of lead roof flashing. Then I
thought about steel flat stock, which
is hard to cut if thick enough or not
enough damping mass if thinner. Then
I thought about the leftover marble tile
that I had from my fireplace!
At 3/8-inch thick, it would fit without much trouble. I am lucky enough
to still have a water-cooled tile saw, so
I cut up some of the scrap pieces that I
had saved and used clear RTV (silicon
rubber caulking) to glue them into place
in the base and under the main deck.
NOTE: Before applying the adhesive,
be sure that it all fits together.
I needed to use a ½-inch masonry
drill to make circular clearances for the
screws in the motor base and grind a
little on one piece to clear one of the
support posts. The cuts do not need
to be very pretty or accurate because
no one will see the marble plates when
4/27/2011 2:36:03 PM
I=gm·Vin
C
gm·V
s·C
gm·Vdiff
s·C
PHOTO 3: Weights added to base.
completed. You could alternately use tile
and one of the score-and-snap-type cutters. Possibly use two layers of tile if it is
on the thin side; whatever space allows.
NOTE: If the bottom fits into a recess,
make sure that the marble and adhesive
are recessed enough to allow the base
to fit correctly. I needed to trim some
excess RTV to make mine fit.
The turntable weighed 14 lbs 9 oz
before the modifications. It now weighs
20 lbs 6 oz.
Does it still howl? No! Measuring at
the turntable location, it is howl-free to well
over 105dB, and that is on a bench top,
not the most solid base for a turntable.
Removing the lightweight clear plastic
cover helps even more if you want even
more of a safety margin. So if you typically play at much lower levels, it may suffice
to just temporarily remove the dust cover.
If you want much more howl-free
volume, the added weights in the base
are very well worth the effort.
I would have added a slab of marble
to the dust cover but the hinges would
not support it in the open position—a
major inconvenience. Next I may try to
add weight to the record center as I have
seen in some high-end SOTA turntables
(www.sotaturntables.com). Good luck in
your endeavors. aX
gm·Vdiff
s·C
g
PHOTO 4: Weights applied to deck.
Brunner611.indd 23
23
4/27/2011 2:36:20 PM
Reliable Reviews
Oppo BDP-93 Blu-ray Disc player
Oppo BDP-93 Universal
Network 3D Blu-ray Disc Player
OPPO Digital, Inc.
2629B Terminal Blvd.
Mountain View, CA 94043
650-961-1118
650-961-1119 (Fax)
www.oppodigital.com
[email protected]
The BDP-93 is Oppo Digital’s latest universal Blu-ray player, replacing the BDP83, which I reviewed in the Aug. 2010
issue of aX (Photo 1). Like its predecessor,
the BDP-93 is a truly universal player,
supporting all major video and audio formats, including Blu-ray, DVD, DVDAudio, SACD, conventional Red-Book
CD, HDCD, as well as a host of popular
file formats. Oppo has added support for
Netflix Instant Streaming and Blockbuster on Demand to this new model (US
only; subscription required), along with
support for .WAV and .FLAC audio files.
The new player includes two assignable
HDMI v1.4a outputs. Having two outputs allows you to connect two HDTV
displays simultaneously, or to dedicate
one for video and the other strictly for
audio. Sending digital audio on the same
cable with video can increase clock jitter,
so separating HDMI audio and video
can be sonically beneficial on a high-end
audio system. The BDP-93 also supports
Blu-ray 3D through both HDMI outputs,
though a 3D television and special glasses
are required. Additional video outputs
include NTSC composite and component connections. For users who wish to
connect an external video processor, the
BDP-93 includes a “Source Direct” mode
which feeds the audio/video content on
the disc to the player’s HDMI output
without any internal processing.
The BDP-93 includes several other
connections on the rear panel, including
eSATA and USB ports for connecting external hard drives and other storage devices that contain media files (Photo 2). Also
included is an RJ45 Ethernet port, along
with a wireless N-adapter, for connection
to the Internet. The N-adapter plugs into
a USB port, and Oppo has also included
a 6′ USB extender cable for locating the
adapter in the most advantageous spot. An
Internet connection is required for interaction with BD-Live content, streaming
from Netflix and Blockbuster, and playing
audio and video devices connected to a
home network. You can also use a network
connection to update the firmware, but
this can also be done from a CD. There’s
Reviewed by Gary Galo
also a second USB port on the front panel.
The new Oppo player includes a full
complement of audio connections, including eight RCA connectors for the
7.1-channel analog audio outputs. On
the new model, the front left and right
outputs are also used for stereo only operation. The player is also equipped with
S/PDIF coax and Toslink optical digital
connections. Two remote control connectors are also included—an eighthinch phone jack for an external infra-red
remote sensor, and an RS-232 port.
The BDP-93 is a visually beautiful player, sleek in appearance with the
black anodized front-panel controls flushmounted, giving the appearance of one
flat surface. Like its predecessor, the new
player is very well constructed, and weighs
in at nearly 11 lbs. The BDP-93 is supplied with the same remote control as the
BDP-83, which is one of the most userfriendly remotes I’ve used. But, it’s much
more directional than before—I have to
point it right at the player in order for it
to operate. I suspect that the directionality
lies in the receiver in the new player, rather than in the remote itself. The 84-page
manual is very well-written and leaves
few, if any, mysteries. The player is nicely
packaged, with the same cloth tote bag
included with the BDP-83.
Chip Details
PHOTO 1: Controls are flush-mounted on the front panel of the Oppo BDP-93, giving
the player a sleek appearance (Courtesy of OPPO Digital).
PHOTO 2: The rear panel of the BDP-93 includes two HDMI connectors, NTSC composite
and component video, eSATA, USB, S/PDIF coax and Toslink digital, eight analog audio
jacks, plus eighth-inch and RS-232 remote connectors (Courtesy of OPPO Digital).
24
audioXpress 6/11
OppoReview611.indd 24
For their new player, Oppo has changed
the video processor/format converter to the
Marvell’s 88DE2750 Kyoto-G2 video processor, a high-performance chip with 2nd
generation Qdeo technology (the Anchor
Bay ABT2010 chip used in the BDP-83
does not support HDMI 1.4, which is
necessary for Ethernet and 3D operation).
In addition to providing state-of-the-art
video with high-def Blu-ray discs, the
Kyoto G-2 chip also features up-conversion circuitry designed to narrow the gap
between conventional DVDs and Blu-ray
HD discs. Network streaming enhancements include video noise reduction, compression artifact reduction, intelligent color,
4/27/2011 2:51:31 PM
Reliable Reviews
contrast, detail, and edge enhancements.
Marvell notes that “The 88DE2750
features a complete suite of advanced video
processing technologies, delivering quiet
and natural video free of noise and artifacts, for a truly immersive viewing experience. The second-generation Qdeo
video processing includes enhancements
to the entire suite of video technologies
and introduces an innovative new technology called Qdeo True Color—a unique
solution for using the full dynamic range
of 10-bit and 12-bit displays. The use of
65nm technology provides industry leading performance at very low cost.” For
more information on this chip, visit www.
marvell.com.
Like its predecessor, the BDP-93 uses
a Cirrus Logic CS4382A eight-channel,
192kHz/24-bit Delta-Sigma DAC chip.
This chip supports Red Book de-emphasis, which Oppo has implemented.
Analog circuitry still consists of Texas In-
PHOTO 3: Inside view of the BDP-93. Counterclockwise from the lower left is the switching power supply, the analog/DAC board, and the “L”-shaped video board. The player is
very well constructed and weighs 11 lbs.



audioXpress June 2011 25
4/27/2011 2:51:35 PM
Reliable Reviews
struments NE5532A op amps with electrolytic coupling capacitors. Oppo has
dispensed with the dedicated two-channel
analog output featured on the BDP-83,
which used Cirrus’s flagship CS4398 stereo-only DAC, and film capacitors bypassing the electrolytics. The BDP-93 has
a switching-mode power supply, making
it compatible with all line voltages and
frequencies. Three-terminal IC regulators
are used for the power supplies—a single
7805 for the digital supply and a 317/337
pair for the analog circuitry. (Photo 3)
Setup and Operation
I used my 42″ Panasonic TH-42PZ85U
plasma television for video evaluation of
the Oppo player. The BDP-93 has an intelligent and intuitive setup menu, aided
by the easy-to-use remote control mentioned earlier. The manual is very clearly
written and illustrated, which first-time
users will appreciate, but users with any
experience at all probably won’t even need
to refer to the manual. Although the “Easy
Setup” will get you started very quickly,
experienced users will probably go for the
more advanced setup options afterwards.
I ran the various demonstrations and
tests on the Spears & Munsil High Definition Benchmark Blu-ray Edition test
disc. The video performance is definitely
on par with the older BDP-83, which is
to say that it’s outstanding. Nearly all of
the tests on the Spears & Munsil disc
performed flawlessly.
On the Source Adaptive Deinterlacing wedge pattern, the Oppo displayed
moiré only in the quarter near the tip
of the horizontal wedge pattern, exactly
as it should be. On the vertical wedge
pattern, moiré appeared on the top half
(the booklet for the test CD doesn’t
specify how the vertical wedge should
appear). This was comparable to the
BDP-83, and far better than my Marantz BD7003. The “Difficult Edits” test
does display some moiré, but this appears to be an extremely demanding test.
The Edge Adaptive Deinterlacing
Tests fared very well. Only the cables on
the “Bridge” showed a bit of stair-casing,
as did the BDP-83 and my Marantz. On
program material, including the “Montage” demo on the Spears & Munsil disc,
I could not find fault with the BDP93’s performance. Picture quality is stellar, and up-conversion of conventional
DVDs to 1080p is the best I’ve seen.
Audio Performance
I’ve never been able to explain why solidstate audio products sometimes require a
break-in period to sound their best, but
I’ve experienced it too many times to
discount it. The BDP-93 definitely improves with age, and after a few evenings
of use it definitely sounds more refined
than it does straight out of the box. The
audio performance on the BDP-93 was
quite similar to that of its predecessor.
I got in the habit of doing my listening with the player set to the “Pure
Audio” mode, which turns off all of the
video circuitry as well as the front panel
display. This makes a subtle but percepti26
audioXpress 6/11
ble difference in high-frequency smoothness with this player. I also found that
the treble region was somewhat grungy
with my other digital hardware—specifically my NAD M-55 player and PS
Audio Digital Link III DAC—powered
up. So, I unplugged the NAD and PS
Audio units for my evaluations of the
Oppo as a stand-alone audio player. This
actually made a bigger improvement in
the treble than the Pure Audio mode.
The BDP-93 gives solid entry-level
high-end performance, with surprisingly
good inner detail in the midrange, and
soundstage that is both wide and quite
precise in localization from left-to-right.
Depth perspective is on the moderate side,
as it was with the BDP-83. The extreme
low bass is quite detailed, if lacking in the
ultimate power of a reference-quality playback system. If there’s any real fault with
this player, it’s in the treble region, which
is somewhat bright in tonal balance, and
congested in fully-scored material. But, for
the asking price of $499, this player will
find few competitors—it really performs
remarkably well for the money.
When I evaluated the BDP-83, I did
most of my listening using the twochannel stereo analog outputs, which
were of higher audio quality than the
multi-channel outputs. Despite not having dedicated stereo outputs, I think the
BDP-93 represents a sonic upgrade from
the older player. What’s most noticeable is a warmer sound in the midrange.
Oppo’s Jason Liao explained that I was
not alone in this reaction, and suggested
some improvements made in the power
supplies and analog filters that might account for it. The BDP-93 also performs
superbly when used as a transport, with
my outboard PS Audio Digital Link III
DAC. As a transport, it holds its own
with my reference NAD M-55 player.
The BDP-93 allows you to play
SACDs either in their native DirectStream Digital mode, or with a conversion to PCM. The conversion to PCM
is done with the same decoding algorithm used in the BDP-83, but I prefer
to hear SACDs in native mode. Support
for .WAV files is a welcome feature on
4/27/2011 2:51:38 PM
Reliable Reviews
the BDP-93. I compared direct playback
of some 176.4kHz/24-bit files that I
transferred from high-quality analog
master tapes with their DVD-Audio
counterparts that I had made from those
files with Discwelder Bronze software. I
was hard-pressed to hear any differences
between them on the Oppo player.
I also tried playing the 176.4kHz/24bit files on the Reference Recordings HRx
DVD of the Rachmaninoff Symphonic
Dances with the Minnesota Orchestra
conducted by Eiji Oue (HR-96, www.
referencerecordings.com). Strangely, these
files would not play on the Oppo player,
even though all files were listed on the onscreen menu. I suspected some peculiarity
with these files, so I tried an experiment.
I opened the three Symphonic Dances files
with my digital editor (Sound Forge Pro
10), saved them to a new folder on my
hard drive, and then burned those files to
a new DVD. The files were not altered in
any way, just saved and copied. The new
files play just fine on the Oppo.
I contacted Marsha Martin at Reference Recordings about this issue, and
she noted that two other customers reported the same problem with the .WAV
files on HR-96, though other HRx discs
reportedly play fine. She and Oppo’s
Jason Liao are working to find a solution,
which may simply require a firmware
upgrade in the player. Marsha kindly
sent me copies of two other HRx discs
for testing: HR-70 (Stravinsky’s Rite of
Spring, Firebird Suite, and Song of the
Nightingale with the Minnesota Orchestra conducted by Eiji Oue) and HR-120
(Britten’s Orchestra with the Kansas City
Symphony conducted by Michael Stern,
including The Young Person’s Guide to the
Orchestra, Sinfonia da Requiem, and the
Four Sea Interludes and Passacaglia from
Peter Grimes). The .WAV files on both
of those discs play fine on the BDP-93.
I’m sure this issue will be resolved by the
time this review appears in print.
For audiophiles who demand true
high-end audio performance, Oppo has
announced the BDP-95 player, which
will be available by the time this review
appears in print (see ad in this issue). The
BDP-95 will have the same video hardware as the BDP-93, but will feature a
linear power supply, the ultra-high end
ESS Sabre DAC chips, and analog circuitry built around National Semiconductor’s high-performance LM4562 op amps.
In a non-scientific poll conducted by
About.com, 56% of the 1542 participants
preferred Oppo Blu-ray players, leaving
Sony, Samsung, LG and Toshiba trailing in the dust with 19, 18, 4, and 2%,
respectively. It’s no surprise—the Oppo
BDP-93, like the BDP-83 before it, offers stellar video performance, and surprisingly good audio, at a very affordable
price, and Oppo has developed a reputation for excellent customer support. The
BDP-93 offers real value in the A/V
market and is highly recommended. rr
Manufacturer’s Response:
We appreciate Mr. Galo’s detailed review
of the OPPO BDP-93 universal Blu-ray Disc
player. With Mr. Galo’s help, we were able
to get in touch with Reference Recordings
regarding the observed compatibility issues
with their HR-96 reference disc. What we
discovered was the cause of the failure was
an extra chunk of data in the WAV file header which the player did not recognize and
was not able to compensate for. Reference
Recordings is willing to re-author the disc,
but we are happy to report that we have a
found a software resolution for the error and
have already resolved it with our latest Beta
Firmware update. Finding and reporting
this compatibility issue is a great example
of how the audioXpress review can help
customers: the reviewer not only brings unbiased evaluation of the products, but also
helps content providers and device manufacturers to identify and resolve problems.
Nathaniel Plain
Tech Support & Marketing Lead
OPPO Digital, Inc
audioXpress June 2011 27
4/27/2011 2:51:41 PM
XPRESSMail
PHONO PHEVER
I have just finished re-reading your December 2010 issue and would like to
compliment you and your authors for
putting together such an excellent compilation of turntable articles. I have a
collection of turntables including a Merrill-modified Acoustic Research beltdrive (BD) with the SME 3009 arm. My
feelings when I use it are akin to playing
a fine violin—it is beautiful but fiddly!
My everyday TT is a Denon DP-45F
automatic direct-drive (DD). It is easy to
use (with no belt to deteriorate) and the
speeds (33.3’ & 45) are always spot on.
I have a question for your turntable
expert readers: why are DD TTs reviled
in the hifi press (Stereophile always features BDs) when they seem to have so
many obvious advantages over BDs?
I’ve listened carefully to sustained tones
while playing a test record and can’t hear
any “warbling” that may be ascribed to
motor speed fluctuation or noise. Additionally, DDs don’t slow down when
they hit heavily modulated tracks.
The discussion of the “split-load” phase
splitter has been a fascinating multi-year
saga. I think it is obvious that provided
the loads are identical then the outputs
will be mirror images of one another (with
or without distortion). Provided that no
grid current flows, the input impedance
at audio frequencies of a push-pull output
stage will always be high. Consider a half
cycle in which the output from the cathode of the totem pole is driven positive to
the point at which grid current flows in
the output tube to which it is connected.
Let the distortion be Dk. Now imagine
a half cycle in which the totem pole is
driven towards cutoff with the plate voltage rising to the point at which the other
output tube draws grid current. Let this
distortion be Dp. Will Dk and Dp be the
same? If not, then alternate half cycles
will generate different levels of distortion.
The common mode rejection ratio of a
push-pull output stage is not very high so
that alternate half cycles may well sound
different.
Andre Routh
Medford, N.J.
Chris Paul responds:
I agree with Mr. Routh. This topic has generated some interest.
The voltages at the P and K of a phase
splitter are equal and opposite (distortion
included) if its loads are identical and linear.
But this all goes to heck in a handbasket
if the loads are nonlinear, even if they are
identical. This is because of the unequal
impedances and therefore drive capabilities
of the PS at the P and K, plus the fact that
only one nonlinear load is being driven at a
time. In such cases, the P and K voltages
are very different, and so are Dp and Dk.
To demonstrate this to yourself on the
bench or in a simulation, connect the following identical nonlinear loads to the P
and K of a balanced, otherwise linearly
loaded PS: 3.3kΩ in series with .1µF in
series with a 1N4007 (or similar) diode,
cathode grounded. Drive the AC-coupled
PS grid with 1kHz at varying levels and observe the P and K waveforms.
Finally, even a balanced PS seeing identical linear loads and driving a distortionless
output stage of infinite CMRR would pass
all odd order distortion products from the
PS. Only the evens would be rejected.
Ron Tipton responds:
In reply to Mr. Routh’s question about directdrive versus belt-drive turntables, I really
don’t know. I suspect that the DDs are considered less “professional” than the BDs.
My turntables are all DDs as is the KAB
Reference Standard (www.kabusa.com).
Perhaps you should direct your question to
John Atkinson, the Stereophile Editor.
TUBE HIGH-PASS FILTER
In Fig. 2 of Paul Stamler’s Passive Preamps article (March ’11 aX, p. 23), C3 can
be eliminated if fixed bias, rather than self
bias, is used for the cathode follower. A 1.5
meg resistor connected from B+ to the
grid, and another 1.5 meg resistor from
the grid to ground, will bias it correctly. C2
sees the parallel value of these two resistors, 750kΩ. R3 and R4 are not necessary
with this circuit. R5 connects directly to
the cathode to ground.
Tom Tutay
Ft. Walton Beach, Fla.
Paul Stamler concurs with Mr. Tutay’s
suggestions.
Contributors
George Danavaras (“Accelerometer Testing of Loudspeaker Drivers,” p. 6) graduated from National Technical University of Athens,
Greece in 1986 with a degree in Electronic Engineering. He currently works in the R & D division for a Greek Telecommunication
company.
Mike Danbury (“Low Frequency Effects Mixer,” p. 16) resides in Orange, Calif.
Darcy Staggs (“LFE Summer, p. 18) has been interested in electronics and its magic since building a crystal set in grammar school
and later equipping this elementary model with the first commonly available transistor amplifier, a GE 2N107. A college education
(MS, engineering) was followed by work on the Apollo Lunar project (simulation of the electrical power system), war gaming,
management software for Swedish IBM, and weapons system simulation.
Dennis Hoffman (“Electronics Grounding,” p. 20) began playing guitar in high school, and soon developed an interest in electronics.
He taught electronics at Heald College for 20 years. During this time he built analog and DSP reverbs, tube analog mixers, and also
earned a BA degree in Management from Saint Mary’s College. In recent years he has been building guitar amps and working at the
SLAC National Accelerator Laboratory as a Science and Engineering Associate.
Patrick M. Brunner (“Make Your Turntable Sound Marbelous!,” p. 22) is the owner of Applied Technical Services.
Gary Galo (Review: Oppo BDP-93 Universal Network 3D Blu-ray Disc Player, p. 24) is Audio Engineer at The Crane School of Music,
SUNY Potsdam, where he also teaches courses in music literature. A contributor to AAC since 1982, he has authored over 230
articles and reviews on audio technology, music, and recordings. He has been the Sound Recording Reviews Editor of the ARSC
Journal (Association for Recorded Sound Collections) since 1995, was co-chair of the ARSC Technical Committee from 1996 to 2004,
and has given numerous presentations at ARSC conferences (www.arsc-audio.org).
28
audioXpress 6/11
XpressMail611.indd 28
4/27/2011 2:50:13 PM
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tutorial
By David Rich
“TVs? We don’t need
no stinking TVs.”
A guide to using Blu-ray and universal players for music lovers.
W
ell, you do need a TV to understand this paraphrase from
the Mel Brooks movie “Blazing Saddles” [which was spoofing “Treasure of the Sierra Madre”—editor]; but
from the audiophile point of view with
an identical center channel placed at the
same vertical height as the left and right
channels, the video processor is irrelevant. If you place the center above or
below the left and right speakers, the
image will bend up or down. Using a socalled matched center-channel speaker
with different speaker alignment introduces other problems that can result in
tonal balance shifts.
While a very expensive front projection system with an acoustic screen can
hide an identical center-channel placed
at the same vertical height (obviously
the 40+ lb LCR speakers must be
mounted in-wall, requiring significant
renovations), a large flat screen display defeats the possibility because the
center speaker in front of the screen
blocks the view. With the big screen
gone, you need a composite video output that is always available to see video
setup screens on the small NTSC (original analog color standard for the US)
TV you have in the equipment rack.
Some competitive units may blank
components when they sense an HDMI
connection, which is very bad news
because the HDMI cable is connected
to the AVR to pass the high-resolution
digital audio signals.
Stereo-only users may well ask why
they need, for example, the BDP-93
(see Gary Galo’s review of this unit on
p. 24). The only viable high-resolution
stereo format appears to be SACD,
so you may think an SACD player is
sufficient. Well, Blu-ray Audio discs
mastered by Pure Audio will have a
two-channel output at 192kHz (Naxos
offers stereo at 96kHz) and do not require a TV to run. Many Blu-ray concert performances with video (watching the performance is optional and
is often distracting as the producer
zooms in on the oboe when you think
the main theme is in the violins) are also
available at 24/96kHz (Dolby or DTS
lossless coding), although you will need
to down-mix the recording to stereo
which is a function some Blu-ray players
have (check the online instruction book
before you purchase) and will need a
small TV to see the start menu.
DVD-A may be an almost obsolete
format as far as new releases are concerned, but it has an important new
role. You can burn high-resolution
downloads on a computer as a DVDA disc. I am not going to go into the
details here. You cannot burn an SACD
on a computer. Not all Blu-ray players
that support SACD support DVD-A,
so check closely before purchase.
ANALOG OR HDMI?
Audiophiles often ask whether they
should use the analog outputs of a
universal player or the digital transmission systems HDMI or S/PDIF
(Sony/Philips Digital Interface Format). This is a non-trivial matter, provided you have full-range speakers.
One alternative to the analog out for
stereo reproduction is an expensive
digital decoder such as the Benchmark
DAC1 (reviewed in the January 2009
issue of audioXpress http://www.
audioxpress.com/reviews/media
/hansen3033.pdf).
Because the Benchmark DAC1 is
connected by S/PDIF or a computer’s
Universal Serial Bus (USB), it cannot
process a SACD DSD stream. You
cannot transcode to PCM because the
SACD specs require all digital signals
that are not copy protected—such as
S/PDIF—to be muted. As far as I know,
no two-channel product will take HDMI
in. You thus must use analog outputs
of a universal player to listen to SACD.
Some universal players have DACs with
DSD inputs to recover the analog signal
in the manner the SACD developer intended. In stereo 96kHz and 192kHz
LPCM (Linear Pulse Code Modulation)
from a DVD-A can go down S/PDIF.
When deploying a stereo system and
bass management for a subwoofer, or
with a room correction system, the isaudioXpress June 2011
RichTv.indd 31
31
5/10/2011 2:29:54 PM
sue is more complex. Analog bass management systems are hard to find, and
while some external room correction
systems may have analog-in inputs and
outputs, the internal processing is PCM.
Most universal players also have internal bass management, but first the DSD
stream must be converted to PCM. You
may need to make changes in the player
format menu. Some universal players
may not do this and will provide no bass
management for SACD.
Another alternative is a multichannel
AVR run in two-channel mode to gain
access to DSP (Digital Signal Processor). This will give you access to bass
management as well as room correction. To gain access to the DSP functions, use HDMI digital at least for
SACD and Blu-ray disc formats. The
S/PDIF receiver may have lower jitter than the HDMI depending on the
AVR, although many higher-end AVRs
and Pre/Pros have Asynchronous Data
Rate Converters which render the jitter on the recovered clock almost insignificant. Obviously, the AVR must
have an output DAC that matches the
performance of the one on the BDP-93
to prevent loss of sound quality.
MULTICHANNEL AUDIO
Coming into your AVR or Pre/Pro
with eight analog cables is complex and
often impossible because many AVRs
are dropping eight-channel in. Almost
none provide ADC conversion on the
eight-channel inputs anymore.
HDMI is almost the only viable option for multichannel audio. Everything
in an AVR or Pre/Pro is done in PCM
including bass management and delay.
If you choose DSD in a “Pure Audio”
mode, all you will get is analog volume
adjustments with no distance compensation. Some AVRs with HDMI 1.2 may
have a primitive bass management system that uses digital filters for the subwoofers that are active in DSD mode
32
RichTv.indd 32
(the band of frequencies to be sent
to the subwoofer are analog-to-digital
converted and sent to the DSP) and a
fixed analog high-pass filter for the main
channel. Spec sheets and instruction
manuals for AVRs that support DSD
may not make this clear. Sometimes, I
have resorted to block diagrams in service manuals for clarification.
Even if the AVR does have bass management in the DSD mode, will the
fixed crossover frequency be optimal
for your system? Not likely.
Good bass management with different types of speakers deployed for the
fronts, rears, and the center requires
the flexibility of setting different crossover frequencies and slopes to the
subwoofer. You also need delay to correct for distance difference between
speakers. Digital filtering and delay is
not practical when processing a one-bit
direct digital stream.
The bass management systems in Bluray and universal players have no auto
calibration with a microphone like an
AVR. You must measure the distance
for each speaker to the listening seat
and use a sound level meter to adjust the
level trims to compensate for sensitivity
differences between the speakers. In
some Blu-ray and universal players you
can select the crossover frequency but it
must be the same for all channels.
Most important for multichannel
is the need for room correction even
in the absence of a subwoofer. First,
room correction will clean up the
room-dominated effects below 300Hz
and, if a sub is in the system, select the
optimum slope for the crossover between the main channels and the sub
(the fixed 12dB octave High Pass Filter
(HPF) and 24dB octave Low Pass Filter
(LPF) used in standard bass management system without room EQ almost
always result in large frequency response changes in the crossover area).
Second, correction above 300Hz al-
audioXpress 6/11
lows matching of frequency response
of all dissimilar-sized speakers. Most
important is center-channel frequency
response normalization by the room
correction if you are forced to use a
dedicated center channel above or below the screen.
In the past, multichannel room correction has been very expensive or
very bad. Now I am seeing these systems in AVRs with good performance
starting at $1000.
HDMI FUNCTIONALITY
For SACD playback, it is highly desirable that your universal player has a
mode to fall back automatically to PCM
transcoding of an SACD disc when the
AVR does not support DSD on HDMI.
A universal player without this feature
can go silent if this menu option was
not constructed properly. I have handson experience that the Oppo players
do this. The Denon and Marantz players call it out in the instruction book.
Another important feature is an auto-detect mode for HDMI audio input
available in AVR or Pre/Pro. A player
with this feature will automatically send
high-resolution Dolby or DTS direct to
the AVR with HDMI 1.3, and will convert the high-resolution to LPCM itself
for the unit with HDMI 1.1. Without
this feature the AVR might go silent
with only HDMI 1.1. Oppo Blu-ray
players have this feature and I tested
that it works. I do not know whether
other Blu-ray players have this feature.
If you let the Blu-ray player do the
decode of the high-resolution Dolby or
DTS, do not be surprised if a 48kHz
sampling rate is reported by the AVR.
Not all Blu-ray recordings are issued at
a 96kHz sampling rate.
ADVANCED FEATURES
If you are planning on purchasing Blu-ray
Audio discs, you need to make sure your
Blu-ray player will work with the Pure
5/10/2011 2:29:55 PM
Audio mShuttle application, which is
used with Blu-ray audio discs mastered
by Pure Audio (www.pureaudio-bluray.
com) technology. mShuttle, it turned
out, was a BD-Live application that sets
up the player as a web server so you
can download music files from it. The
specification sheet of your Blu-ray player
should indicate that it supports BD-Live
applications with 1GB memory.
I tried to use a Pure Audio mastered
Blu-ray disc with this mShuttle feature.
One leg of the networked Ethernet
cables goes to the back of the Blu-ray
player. On a computer connected to
the network, you should be offered for
download lossless and MP3 files containing the music on the Audio Blu-ray after
supplying the correct port address to
your web browser. You can use these
files to burn a CD or load a music player.
The Oppo Blu-ray players I have had
access to (BDP-80 and BDP-93) did
all the networking without my having
to do anything but get the IP address
from the network setup window. For
those who choose to listen to Blu-ray
without an Ethernet port or a TV, I
can report that with the Oppo players
things worked perfectly with Pure Audio Blu-ray audio discs. All options (five
channels or seven channels at 96kHz
sampling or stereo at 192kHz) were
made available using only the controls
on the remote.
It is useful if your Blu-ray player can
read MP3, FLAC, and WAV files off
a memory stick. If the player is well
designed the MP3 files even displayed
information on the work and the performer on the TV screen. FLAC files
encoded as 96kHz or 192kHz should
be bit-accurate at the S/PDIF or HDMI
outputs. It is also important that your
Blu-ray player can read MP3, FLAC or
WAV files you burn to DVD on your
computer. I like this very much because
I can purchase high-resolution down-
loadable files but store and use them
like any disc media. I put then in blank
jewel boxes along with the music and
performance notes that are available
with the files.
Just becoming available are multichannel FLAC 5.1 files. I have tested
these with Oppo players and out comes
multichannel sound. This looks as
though it could be the feature in which
multichannel sound is distributed, especially as the number of SACD and universal multichannel players decline and
the prices of the remaining units are
going up. Like two-channel high resolution music files, you can burn these
to DVD and your Blu-ray player should
play them. This worked when I tried it
with an Oppo BDP-93. I do not know
whether other units will do this. You
can prepare a DCD-R with FLAC 5.1
files on it and take it to the store to
see whether the Blu-ray player you are
interested in will work with it.
RichTv.indd 33
33
5/10/2011 2:29:58 PM
LEARNING TO SPEAK MULTICHANNEL
DSD (SACD encoding). Direct Stream Digital is a very highspeed single-bit format. The sampling rate is 2.81MHz, which
is 64 times the CD sampling rate of 44.1kHz (remember: CDs
have a bit depth of 16, so the data rate of a CD is 705kbits/sec
per channel). The quantization noise of a one-bit signal is extremely high. A DSD stream can be filtered with a high-order
analog filter connected to the one-bit DAC, which eliminates a
pair of digital filters required in a PCM-based system. This is the
advantage of DSD claimed by its proponents.
If a one-bit stream at a 2.8MHz sampling rate is band limited
to 50kHz, its quantization level is equivalent to a 5-bit PCM signal. We go from one-bit to a five-bit equivalent because we are
oversampling (only ~110kHz sampling is needed to reconstruct
a 50kHz signal). Sampling at 2.8MHz and filtering at 50kHz to
get a better SNR is an example of processing gain.
Five-bits will provide a signal-to-noise ratio (SNR) of ~31dB,
worse than an AM radio. Noise shaping is used to improve SNR
by moving the quantization noise from the band of interest (0
– 50kHz) to the band to be filtered out (50kHz to 1.21MHz).
Even with noise shaping, DSD carries less information (Shannon’s channelcapacity, en.wikipedia.org/wiki/Channel_capacity) than a PCM system at a 24-bit depth and a 96kHz sampling
rate (2.3Mbits/sec data rate).
In theory, the SNR of a 24-bit PCM is more than 145dB
out to 40kHz (96kHz sampling), which is evident in the Oppo
BCD–83 measurements (aX Digital, September 2010). Compare the 1kHz residual distortion of the 96kHz PCM encoding
(Fig. 14) with an SACD DSD signal (Fig. 15). Practical issues in
the Oppo digital-to-analog converter (DAC) and analog circuits
limit the SNR to ~114dB.
Other problems with SACD exist. For more information, see
my Stereophile article on the web (www.stereophile.com/features/374). From a practical perspective, both DSD and PCM
at 24-bit depth at a 96kHz quantization produce an audio signal with noise and distortion components well below our aural
limits and should sound no different.
Editing and mixing in the DSD domain require special equipment. The fact that people spend so much time and money to
produce DSD material, as well as the fact that Sony and Philips
chose DSD over PCM (the DVD-A format released at the same
time) indicates many professionals perceive it as audibly superior. The resulting DVD-A versus SACD format war killed both,
because designing a universal player added significant cost and
consumer confusion.
SACD won the market over DVD-A not for its aural advantages but because it was backwards-compatible to CD. In addition, some DVD-As required a monitor to select operational
34
RichTv.indd 34
audioXpress 6/11
modes before the disc would play. Blu-ray Audio will also not
play in a CD player and thus has the same problem as DVD-A.
The assumption of the secondary importance of CD compatibility in an MP3 and digital server world will be tested going
forward. Blu-ray Audio, unlike some DVD-As, will play without
a TV. Pure Audio Blu-ray discs provide lossless and MP3 files
for a workaround for server issues and CD compatibility. With
the lossless files you can burn a CD on your computer. Naxos
Blu-ray Audio discs do not have these files.
For more info on SACD, go to the FAQ on the SA-CD.net
website: www.sa-cd.net/faq#general2.
HDMI is a single cable that can contain encrypted digital
audio and video. It is the only digital cabling system in use
today that transmits HD video and higher resolution analog.
HDMI, an acronym for High-Definition Multimedia Interface,
has evolved over the years and continues to do so.
The HDMI receiver of whatever equipment you purchase
will be obsolete in about a year. Lucky for audiophiles, the audio transmission is relatively mature. Major changes are designated by a change in the revision number while smaller changes
have a letter after the number. The HDMI working group is
now asking equipment manufacturers not to include the letter
increments even though they are important because they indicate specific changes to the HDMI transmitters and receivers.
Here is a summary of the audio changes:
* Video changes come so frequently and are often so complex
that products with the newest HDMI may have bugs that require
firmware patches that can sometimes be done by the user.
* HDMI 1.0 was two-channel audio only.
* HDMI 1.1 added the transfer 7.1 channels of lossless highresolution PCM as well as the Dolby Digital and DTS formats used
on a standard DVD. DVD-A is supported by HDMI 1.1 because it
is encoded in lossless PCM at sampling rates up to 192kHz.
* HDMI 1.1 is sufficient for listening to all discs in the best
sound of all audio and video discs because all current Blu-ray
universal players will transcode SACD. Every Blu-ray player, including the $100 ones, also decodes Dolby True HD and DTSHD to high-resolution PCM. Obviously, no SACD or DVD-A
support will be found on a $100 player.
* HDMI 1.2 adds the ability to transfer DSD signals. This was
the first universal digital cable format to transfer a DSD signal
stream from an SACD to an amplifier, which had to have a 1.2
HDMI receiver.
* Today, many AVRs and Pre/Pros do not support HDMI
1.2. They require the source player to transcode the DSD to
PCM and allow the HDMI 1.1 standard for high-resolution
PCM to be used.
The fact that HDMI 1.2 was finalized in 2005 with very lim-
5/10/2011 2:30:00 PM
ited product availability for another couple of years is partially
responsible for the failure of SACD. From the SACD introduction in 2000 to 2007, when equipment to transmit and receive
data of an SACD finally appeared, you needed six analog cables
to connect to the multichannel amplifier.
Staying in DSD until one-bit DAC conversion to analog eliminated many important digital signal processing features necessary for optimum multichannel listening. Absent the signal
processing, and with a high probability the consumer may not
have connected the six cables correctly (e.g., center mistakenly
connected to right rear), many might conclude multichannel
was not an improvement over stereo in the seven years before
HDMI was made to work for SACD.
* HDMI 1.2a added features that enable components to control functionality of other components.
* HDMI 1.3 adds the ability to transfer high-resolution lossless formats from a Blu-ray disc. These are Dolby TrueHD and
DTS-HD. The Pre/Pro or AVR then converts these to highresolution PCM. Decoding provides only limited advantages
especially in a five-channel environment.
* HDMI 1.3a only provided video improvements.
* 1.3ba1 and 1.3c were mostly fixes for video and component control features added along the way and did not enhance
functionality.
* HDMI 1.4 adds an Ethernet channel for Internet and home
network connectivity (including audio). It also has bidirectional
audio transmission. With an HDTV driven by an antenna, the
audio from the TV can be sent to the AVR or Pre/Pro with
HDMI 1.4, so you can hear sound from both the TV and your
home theater. In video, this is the format for 3D as well as
higher resolution video.
* HDMI 1.4a involves issues arising from added formats for 3D.
To summarize, HDMI 1.1 is all you need to listen to all discs in
the best sound because all Blu-ray universal players will transcode SACD. They also decode Dolby True HD and DTS-HD to
high-resolution PCM.
More information on HDMI standards written for the average person can be found at:
www.hometheater.about.com/od/hometheatervideobasics/qt/ hdmifacts.htm. Wikipedia (www.en.wikipediaorg/
wikiHDMI) provides information on the ordinal and alphabetic
revisions in more detail than a videophile could want.
Audio details are not that much more specific than what I wrote
above because they tend to be static and audio transmission is
much simpler than video. You do not need to read the Wikipedia
entry. With HDMI 1.1 you are all set for audio. Videophiles are
constantly playing catch-up with all the revision changes.
Multichannel Preamp Processors (Pre/Pro). Preamp
Processors have DACs and DSPs (the processor) for decoding digital audio inputs, performing bass management, speaker
distance correction, room correct, and conversion of the digital
signal back to analog. The preamp section is similar to a stereo
unit, but with 6-10 channels. A direct mode will bypass the
processor part allowing analog inputs to go direct to the analog
volume controls.
An Audio Video Receiver (AVR) is a Preamp Processor
with power amplifiers also in the chassis. Most modern Pre/
Pros and AVRs support video switching and processing as well
as audio. Some have Ethernet, USB, or iPod ports to support
computer networking, MP3 players, and music servers.
Audiophiles would like to purchase a unit with good audio
performance and features, but skip the networking and video
processing. Unfortunately, it does not work that way most of the
time. As you move up a company’s product line, you find that
audio is the last thing to get upgraded. For Best Buy’s consumers, high-quality audio reproduction is rarely a priority. Products
oriented to the custom-installer market may see improvements in
audio performance sooner as the product line increases in price.
SACD player. This sounds simple. An SACD player is a CD
player that also plays SACD. However, complexities creep in.
Only one SACD player (no video disc support of any kind) has
an HDMI 1.2a output. Some have proprietary digital outputs that
only work with the same manufacturer’s up-market Pre/Pro or
AVRs. These were attempts to get a digital connection before
HDMI 1.2 showed up, but high prices of equipment and the need
to purchase from one company resulted in only a few being able
to hear the advantages of a digital DSD link. Not many in a showroom would have heard a demo with this technology.
Many current SACD players are very expensive units that may
have only stereo analog outputs. Some have told me—but I cannot verify—that most SACD players are used in stereo systems.
To go multichannel, do not purchase just an SACD player.
Instead, get a Universal Player (discussed below).
S/PDIF (Sony/Philips Digital Interface Format). This is the
original stereo digital cable for transmitting data from a CD player
to a digital preamp or digital decoder box. It is available in coaxial
or optical forms. Later, this was upgraded to transmit higher-resolution two-channel signals as well as 5.1 Dolby Digital.
Universal Player refers to a DVD player that can play DVDA and SACD. A Universal Blu-ray player also plays Blu-ray discs.
Every standard Blu-ray player can play Blu-ray Audio discs. A
few Blu-ray players will play SACD but not DVD-A. While DVDA is close to dead for newly issued discs, it is important for those
who want to archive a downloaded high-resolution file. You can
burn a DVD-A but not an SACD on your computer. Details of
how to do this are not addressed here. aX
RichTv.indd 35
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show repor t
By David J. Weinberg
Annual Consumer
Electronics Parties
E
arlier this year, the consumer
electronics industry held its annual new year’s parties in Las Vegas, which comprised Storage Visions
(www.StorageVisions.com), the Consumer Electronics Show (CES; www.
CESWeb.org), Pepcom’s Digital Experience, Showstoppers, the ALMA Winter Symposium (ALMA International;
www.ALMAInternational.org;
used
to be the Association of Loudspeaker
Manufacturing & Acoustics), T.H.E.
Show (www.THEShowLasVegas.com),
and the Adult Video Network’s (AVN)
Adult Entertainment Expo. I only got to
the first four.
Digital Experience and Showstoppers are press events, by-invitationonly. Each hosts more than 100 exhibitors, enabling us to see many new
and prospective products and talk with
companies’ representatives in a much
more compact space than the Las Vegas Convention Center (LVCC).
Storage Visions is a compact conference for information technology professionals, with about 35 exhibitors.
Its sessions focus on the evolving tendencies in content creation, protection,
and storage. With all consumer electronic devices having become specially
purposed computers, many of which
require protected storage of massive
amounts of personal data (including
e-mails, photos, and videos), the topics addressed by this event are critical,
even though the general public is unaware of their relevance.
36
In contrast, the Consumer Electronics
Show almost exceeds man’s comprehension of complex space. The 2011 CES
boasted 2700 exhibitors and claimed
140,000 attendees. The one small saving grace was that all except the highend audio exhibits were in the LVCC,
eliminating most of the need to travel to
another venue. If only all the press conferences also could be held there.
Companies appear to be increasingly
optimistic, as I saw larger booths, with
at least one that appeared bigger than
the neighborhood I live in!
The green initiative continues to be an
important and effective part of companies’ marketing programs, as shown by
signs all around the show floor, although
I am not aware of any studies that have
included a holistic analysis of its costs
and benefits. Organizations and companies appear to have carefully selected
the parameters used in their campaigns
to generate the impression that they are
conserving natural resources.
Data Storage, Protection,
and Privacy
The prices of solid-state drives (SSD) are
dropping while performance is improving. However, there are trade-offs between hard disk drives (HDD) and SSDs.
In an SSD, each memory location has
a limited number of read/write cycles
before the available tunneling electrons
are depleted, permanently ending that
location’s use. Some SSDs include a
firmware algorithm aimed at balancing
audioXpress 6/11
Weinberg611.indd 36
the use of its memory locations.
On HDDs, it takes one write cycle
to write to a memory location. Writing
to an SSD’s memory location requires
at least two cycles: one to erase the location, then a second cycle to write to
it. In addition, if a specific block is addressed for a write, any of that block’s
data to be kept must be moved prior to
executing the write command.
Thus, the read/write cycle time and
life of an SSD is not directly comparable to that of an HDD.
The same is true of the claimed read
and write speed gain of an SSD over an
HDD. It is true that the read and write
data rates of an SSD are higher than
those of an HDD, but the difference
is much greater for random reads and
writes than for sequential reads and
writes (such as when used for recording or playing back a music file).
I was given a copy of Screen Future:
The Future of Entertainment, Computing
and the Devices We Love (Photo 1, Intel
Press; ISBN 978-1934053263; 307 pages; 2010; $14 at www.Amazon.com)
by Intel’s Consumer Experience Architect Brian David Johnson, who “develops future products for Intel, [works
in] artificial intelligence, robotics, and
using science fiction as a design tool.
[He is also a science fiction author], has
directed two feature films, and is an illustrator and commissioned painter.”
The printed book includes a URL and
serial number for access to a companion
website and the digital edition. From the
5/10/2011 2:31:46 PM
At recent CESes I find myself investigating fewer audio and video devices,
focusing more on the computer accessories and peripherals that make our
lives a bit more convenient.
Audio
PHOTO 1: Screen Future.
dust jacket: “Screen Future is about the
people, technology, and economics that
are shaping the evolution of entertainment. . . [It] is both a comprehensive
analysis and an entertaining tour of the
technical, economic and cultural implications that’s coming faster than you
might think.” I plan to read it soon, as
from a cursory scan it looks interesting.
For those who trust their files to be
secure on Internet storage, www.SugarSync.com offers a free plan including
5GB of file space. This is but one indication of the widespread marketing efforts
to get you to rely on others for safekeeping of your files, even while external personal computer storage devices
offer a lot of file space at very low cost.
PHOTO 2: Triton Two.
I have seen little, if anything, innovative
in loudspeakers for more than two decades. However, there were a few audio exhibits I found interesting.
Sandy Gross (GoldenEar Technology;
www.GoldenEar.com) repeated his CEDIA demonstration of his Triton Two
tower speaker (Photo 2 , $1250srp),
in one of the Venetian Tower’s suites.
While the acoustics and size of the
room changed the sound (as you would
expect), the qualities that I found appealing at CEDIA were still present. He
has expanded the line to five models,
including two satellites and two subwoofers, and also offers them in “cinema” combination configurations.
IsoMike (isolated microphones; www.
IsoMike.com) is a special microphone
configuration project of Ray Kimber
(Kimber Kable; www.Kimber.com)
that results in some very fine-sounding
recordings, many of which can be purchased on the website. Details are available on the website, but you have to
search a bit to find them. In the IsoMike
demo room in the Venetian towers, Kim-
ber played an excerpt from the 2007
IsoMike recording of Mendelssohn’s Octet in E-flat major, Op. 20, performed by
the Academy of St. Martin in the Fields
chamber ensemble. The sound quality
was spectacularly clear with a realistic
sense of the performance hall. He also
played an excerpt from a solo piano recording (a Steinway on full-stick, in an
800-seat hall, with the IsoMike located
20′ from the piano) that captured the intimate natural sound of the instrument. A
drum corps piece included a loud cymbal
crash that was much cleaner than I have
heard on commercial recordings, and the
percussive nature of drum strikes came
through in all their glory. The recordists
and their IsoMike deliver great sound.
Surprisingly, the speakers were Sony SSAR1s (Photo 3, ~$27,000/pr in Japan;
US pricing TBD), a four-driver, threeway, floor-standing vented-box system.
Atlantic Technology (www.AtlanticTechnology.com) has announced their
WA-50 wireless (Photo 4, 2.4GHz
band) transceiver system ($200srp
for a set; $90srp for each additional
receiver; look under the website’s
<Products><Subwoofer> subheading).
It can send full-bandwidth CD-quality
one- or two-channel audio to self-powered speakers, solving the problem of
feeding audio from the main system to
other rooms or outdoors (the specs
PHOTO 3: Sony SS-AR1s.
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5/10/2011 2:31:47 PM
PHOTO 4: WA-50.
PHOTO 5: ATH-ANC23.
claim distances of up to 50m). It is
especially useful for systems with multiple subwoofers (many of which are
self-powered), because one transmitter can send to multiple receivers (time
delay <10ms). The transmitter has microUSB 2.0 and analog (1/8″ stereo
jack) inputs, to work with computers
or sound system sources.
Audio-Technica (www.Audio-Technica.com) introduced the ATH-ANC23
(Photo 5, $100srp) QuietPoint in-ear
active noise-canceling headphones that
claim 20dB ambient-noise reduction.
An ambient-pickup microphone located
in each earpiece provides the signal for
the active noise-cancellation circuitry.
Etymotic Research (www.Etymotic.
com), well-known for their hifi earplugs
and earphones, unveiled their highfidelity electronic BlastPLG earplug
(EB1, typically for hunters and military
personnel: $450srp/pr; EB15, for users in continuously noisy environments:
$500srp/pr)—a battery-operated earplug that permits natural hearing under
low-noise conditions, yet senses a loud
impulse noise, such as a gunshot, and
quickly attenuates the sound level to
protect your ears from explosive blasts.
Video
Video displays have become more important in that I believe that the consum38
er is being hoodwinked with marketing
campaigns that ignore existing video display and production industry standards,
and the fact that it is possible to deliver
to the viewer a movie and TV image that
is quite close to that produced by its cinematographers/videographers. With
very few exceptions, the displays on
trade show floors, using manufacturers’
carefully chosen source material, are adjusted in “torch” mode, just as they are
in Best Buy or any other mass retailer’s
stores. This setup is far from properly
calibrated, and substantially distorts
the image’s color, detail, and gray-scale
performance, thus preventing anyone
from making a fair judgment about the
display’s capabilities beyond its functions
and how “pretty” its image can be.
I have no problem with consumers
wanting pretty pictures, but I believe
they should understand that there is
the potential to view an accurate image
and that adjustments away from the parameters defined by industry standards
diverge from that reference. This is no
different than knowing that adjusting
the bass and treble controls make the
audio signal different from the reference, which is the recording.
Digital Production BuZZ (www.DigitalProductionBuZZ.com; 6-7pm Pacific
time, Thursdays; can subscribe through
iTunes) is “talk radio for digital production, post production and distribution.”
Larry Jordan’s free monthly newsletter
is available at www.LarryJordan.biz/
newsletters.
Brite-View
(www.Brite-View.com)
has two products that wirelessly transfer uncompressed HD-video PC-to-TV
($160srp and $210srp), the Air HD
(Photo 6, $280srp) to wirelessly transfer
uncompressed HD video between any
source and display with HDMI connections, two media players that also stream
programs and includes a BitTorrent
downloader, and LinkE devices that use
the power line for 200Mbps networking.
audioXpress 6/11
Weinberg611.indd 38
Honestech (www.HonesTech.com)
offers VHS to DVD 5.0 Deluxe (Photo 7), which includes: the software; a
small box that digitizes analog composite video and analog L/R audio, feeding
it to a USB 2.0 output; an A/V analog
3RCA-3RCA cable and a USB-miniUSB
cable—everything you’ll need to get
your VHS tapes into your computer
and master/burn a recordable DVD.
CES Press Conferences
Unlike last year, 3D was not the mosttouted or the first subject raised in any
of the press conferences I attended.
Companies are connecting their displays to the Internet, and putting apps
and functions in them that allow direct
Internet access for streaming content
and ancillary program information
without use of a separate PC. In other
words, they’re moving toward replacing
many PC-based Internet operations with
TV-based apps and connections such as
Facebook, Hulu, and Skype. The problem they seem to ignore is that most TV
viewers just want to use their TVs to
watch programs, not to search the Inter-
PHOTO 6: Air HD.
PHOTO 7: VHS to DVD 5.0 Deluxe.
5/10/2011 2:31:49 PM
net or interrupt their viewing with other
activities on the same screen.
Smartphones are starting to include
HDMI connectors to facilitate upload/
download of content, and presumably to
facilitate simpler backup of the data and
settings on these portable devices that
are increasingly the hub of people’s lives.
Wayne Park (LG Electronics North
America CEO/president) spoke about
appliances, mobile phones, displays and
“connectedness”; preparing for future
business; and implementing a quality
management system that emphasizes
“responsibility in all employees without
fear of failure.”
The LG buzz-phrase this year was
“competitiveness, preparedness, quality, and people.”
On the side of a hotel across from
the convention center was a 70′-tall LG
poster with the caption: “Smarter LG
knows what you need before you do.”
Confident? or Arrogant?
Panasonic
(www.Panasonic.com)
bragged about their “end-to-end 3D
solution” that includes still and video
cameras and 3D displays. Panasonic
has representatives involved in a multiorganization effort to develop a single
standard for 3D-eyeware interoperability among various manufacturers’ products. In keeping with the times, ecological concern was mentioned, as was its
displays’ Internet-connectivity. Panasonic’s VieraCast IPTV features have
been expanded to include Viera Market,
which offers personalized viewing and
access to apps that can be loaded on
the display, as well as more sources for
streaming programs. Its car entertainment systems feature touchscreen control. Campus Movie Fest (www.CMF3D.
com; a student film festival) participants
are being given use of Panasonic 3D
camcorders for their projects.
Sharp USA’s (www.SharpUSA.com)
CEO/chairman Kozo Takahashi put
his emphasis on energy efficiency in
manufacturing and product operation.
As expected, Sharp representatives
spoke about Quattron HDTVs; Wi-Fi
connectivity; Aquos HDTV on-screen
help with Internet-based remote access
for diagnostics, setup, and control by
Sharp online technical support personnel; and the ability of certain models
to automatically detect connected devices. Sharp’s XV-Z17000 3D front
projector (Photo 8, $5,000srp with
two pair of 3D active-shutter glasses)
is DLP-based and has two HDMI 1.4
(with 3D over HDMI) connections.
They also promoted soundbars, the
Galapagos e-media tablet (Photo 9,
with µSD card slot; it supports XMDF,
a content format popular in Japan), and
their e-bookstore.
Sony (www.Sony.com) put on their
usual show in their huge booth, featuring a screen that looked to be about
70′ wide (~4:1 aspect ratio) on which
to run their promos including a big 3D
demo. “TV redefined” was the catch
phrase as they talked about connected
devices and the Playstation Network
(PSN;
http://US.Playstation.com/
psn/)—Sony’s “destination for entertainment”—with a wide assortment of
3D products and 3D content available
24/365. They also spoke of “Sony’s
3D total solutions,” comprised of movies, professional/consumer still/video
cameras, camcorders, PCs, media/
disc players, and displays. Sony has
started Qriocity (How do they come
up with these names!?!), a video/music
download service apparently to com-
pete with iTunes; Sony certainly owns
enough source material. Sony’s Howard Stringer said that Sony is aiming
to “actively engage consumers in what
has been a passive medium.” Sony/Ericsson’s new smartphone has an HDMI
connection and runs on Android’s latest version, called Gingerbread (I’m
surprised Android versions aren’t
named after dog breeds).
Casio’s (www.Casio.com) big announcement was its Imaging Square
(http://Art.Casio.com) online service
that lets consumers add effects to their
photos, store their projects, and share
their images with the world. This service is not to fix your photo, but to help
you add artistic effects (such as turning
a photo into impressionist “art”). Casio has a new Exilim TRYX 12MP camera (Photo 10, $250srp) that is almost
as small as a credit card (and ~0.6″
thick) and claims “full HD 1080 movie
capture (H.264)” plus simplified direct
connection to social networks.
Noel Lee began his press conference
with Monster’s (www.MonsterCable.
com) headphones, especially the Beats
Pro ($450srp), and Monster’s surround
recordings, such as the remix of Miles
Davis’ Sketches of Spain that comes with
the Miles Davis Trumpet ($350srp) or
Miles Davis Tribute ($500srp) in-ear
headphones. Also new is Monster’s Tron
Daft Punk special edition premium headphones (Photo 11, $350srp) that are sold
with a CD of the Daft Punk Tron: Legacy
soundtrack encoded in High Definition
Headphone Surround (HDHS). HDHS
PHOTO 8: Sharp XV-Z17000 3D front projector.
Weinberg611.indd 39
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5/10/2011 2:31:50 PM
PHOTO 9: Galapagos e-media tablet.
PHOTO 10: Exilim TRYX 12MP camera.
is Monster’s name for their application
of AstoundSound to the discrete fivechannel master to generate a two-channel mix that gives the listener virtual surround sound through headphones; it will
also deliver some of the same effect via
two-channel-stereo speakers. Monster
continues expanding their HDMI cable
strategy with an assortment of microHDMI cables (thinner and more flexible)
for smartphones and other devices. Lee
didn’t ignore 3D, as he talked of the Max
3D active-shutter glasses that he claimed
will work with all 3DTV technologies
($230srp for kit of glasses and RF transmitter; $160srp for additional glasses).
For car use, Monster offers hands-free
accessories featuring hand-motion control to operate i-devices.
are sprouting dual screens in a foldout
form factor. Two examples are from
Entourage Systems (www.EntourageEdge.com), which makes the enTourage eDGe (Photo 12 , $500srp) and
the Pocket eDGe (Photo 13, $350srp),
which include the functions of an ereader, notepad, web browsing with Wi-Fi,
audio/video record/playback, and
more. They are based on the Android
OS, so other apps can be installed.
There were many exhibits of iPeripherals and iAccessories. Among the
more interesting devices were:
- Free One Hand (www.FreeOneHand.com; $40srp) iPad holder and
stand. The iPad is fairly heavy with a
moderately large screen, so most people hold it along one edge while using
the other hand on the touchscreen.
This can be tiring for the holding hand.
Free One Hand is a light, sturdy frame
that clips on the corners of the iPad,
and has a knob in the rear center that
acts as a handle (making the iPad less
fatiguing to hold), and as a fulcrum
tilts the iPad on a table in either the
landscape or portrait orientation. It is a
good solution if you often hold the iPad
during use. Its negative characteristic is
that the projecting knob prevents the
iPad from being slipped into any of the
slim iPad cases on the market.
PHOTO 11: Tron Daft Punk headphones.
- The Tab Grip (www.TabGrip.com;
$40srp) is a similar accessory that
might enable your iPad to fit in some of
the cases. It comprises a flat panel with
¾″ thick “handles” that clip over each
of the four iPad edges and make the
iPad easier to hold in one hand. Part of
each handle is a hinged leg that can be
extended, in pairs, to become a stand,
positioning the iPad at either a shallow
or steep angle in either landscape or
portrait orientation.
- Vogel’s RingO iPad mount system
(www.iPadOnTheWall.com/usa) is similar to the Free One Hand, but without
the knob. This system has a mounting
The iWorld
According to one report there were
more than 80 tablet PCs at CES, plus
various ereaders, and one company—Live
Editions (www.LivEditions.com)—offers
“a multidimensional, complete, cloudbased publishing solution for the digital
world”; in other words, a site to help you
author and publish your own ebooks.
Small iPad- and ereader-sized devices
40
PHOTO 12: enTourage eDGe.
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PHOTO 13: Pocket eDGe.
ring in the center of the back that allows
connection of a knob (for holding or adhesive mounting), a table stand, a wall
mount, a flip stand, or a flex mount.
The price ranges over $70-120srp, depending on the stands included.
- The Breffo (www.Breffo.com) Spiderpodium, a very clever and flexible device, comes in two models: for
iPhone-sized devices ($20srp) and for
iPad-sized devices ($35srp). The larger
model comprises a 1/3″-thick 1¼″ ×
3″ hub with four four-section 5″ adjustable legs protruding from each side
that can be wrapped over the edges of
the tablet, or some of the legs can be
positioned as stand-up supports. If the
hub is pulled away from the rear of the
tablet the Spiderpodium can be used as
a single-hand holder. It can also be bent
into shapes to hang your cellphone, media player, or GPS on your car’s dashboard or sunshade, or on your bicycle
or motorcycle. Another use is as an adjustable camera/camcorder tripod.
- Hypermac’s Hyperdrive (www.
Hyperdrive.com; $100-600srp) hard
drive (5.25″ × 3″ × 1″) adds up to 1TB
storage plus USB ports and card readers to the iPad via the Apple camera
connection kit and a USB cable. It also
comes in models that work with Windows and Linux systems.
- Dexim manufactures an assortment
of Blackberry and iAccessories that
include auxiliary power, including the
P-Flip (Photo 14, www.Dexim.net/us/
products/P-Flip.html).
- Golla (www.Golla.com) offers a
wide assortment of colorfully designed
bags, sleeves, and covers for the iPhone,
iPods, iPad, Macbooks, and cameras.
- ThermaPAK (http://ThermaPAK.
com) has expanded their product line
to include passive heat-absorbing pads
for the iPad and netbooks.
- Aprese (www.Aprese.com) offers
products and services to businesses to
help them rent/sell and deliver/beam
apps to their end users’ mobile devices.
- Avatron (http://Avatron.com) develops apps for the Apple i-devices, including Air Display (which enables use of
the iPhone or iPad as a second monitor
on a Mac OS X or Windows PC), Air
Sharing (use your iPhone as an external drive), and Print Sharing (wirelessly
print from your iOS-based device).
- Clingo (www.Clingo.com)—“Look
ma, no hands!” for hands-free use, especially in cars, in the office, and other
places where it is either mandated or
advantageous to temporarily mount iPod-sized devices for hands-free or onehanded operation. The various stands
($20-35srp depending on the model)
mount easily and flexibly, and securely
hold your cellphone, iPod, almost anything but a large tablet. The stick-um
grip is strong, with easy release, and is
easy to clean. It is a very clever design.
- iWatchz (www.iWatchz.com) launched
the iPod Nano watch, a watchband
system that enables users to transform
their iPod Nano (6th generation) into
also being a wristwatch.
- Jorno (www.JornoStore.com) makes
a Bluetooth keyboard (8.5″ × 3.5″ ×
0.3″; $100srp) that folds up (3.5″ ×
3.5″ × 1.2″) for storage and transport.
Useable with a variety of iOS, Android,
Windows Mobile, and other devices.
Mashed Pixel’s Surc (www.GetSurc.
com; $70srp) is a universal learning remote case and app for the iPhone, and
is being developed for the iPod Touch
and iPad. The iPhone version is scheduled for late-spring/early-summer release; it is in production. Apple has approved the case and app for use on the
iPhone 4. Mashed Pixel will next seek
approval for use on the iPhones 3G
and 3GS, then for the iPod Touch and
the iPad. The app works on all but the
iPad (a separate app is being developed
specifically for that device). The Surc
can be programmed with codes from
Mashed Pixel’s equipment database,
PHOTO 14: P-flip.
Weinberg611.indd 41
41
5/10/2011 2:31:53 PM
and is also a learning remote, able to
be taught commands from the equipment’s original remote.
Zero1.TV’s
VooMote
ONE
(www.VooMote.TV/one_product_
page/?page_id=177; $70srp; scheduled for first quarter 2011) is another
iPhone and iPod touch case and app
that creates a universal remote, identifying devices through their database
and using your device’s original remote
to teach the VooMote the control
codes. App upgrades will be available
through the Apple App Store.
There were many others, including
Evouni (www.Evouni.com; luxury accessories), Gecko (www.GeckoGear.
com), M-Edge (www.MEdgeStore.
com), Mophie (www.Mophie.com),
NLU Products (www.NLUProducts.
com) and SkechIt (www.SkechIt.com).
iTablet (www.iTablet.com) has conscripted the “i” for their name and
their products: tablet computers that
run on the Windows or Android OSes.
PrivacyStar (www.PrivacyStar.com)
offers a for-fee service ($3/month)
providing “real caller ID and unlimited
call blocking” for smartphones and
VOIP that claims to be more comprehensive and effective than the federal
government’s Do Not Call registry
(although they provide a link to register your phone numbers and file complaints there). The PrivacyStar service
for Blackberrys and Android-based
phones can block unwanted callers
and report violators, block private or
unknown callers, block exchanges, offers on-demand caller ID that identifies
some unannounced callers, and also
block text messaging (Android phones
only). Some of these functions might
not work on older models, depending on the OS version installed. Most
of these capabilities will be available for
VOIP phones. The company is planning
to develop some of these services for
conventional cellphones and landlines.
42
Miscellaneous Exhibits
Accurate weather data is always valuable. I have been getting mine from the
Weather channel and weather.com for
years, assuming it was generated directly by the National Oceanic and Atmospheric Administration (NOAA, the
source of all weather data in the US). At
NOAA’s CES booth I learned that each
of those sites was two generations away
from NOAA’s source data, and that they
and the various local TV-station weather
reporters used their own algorithms to
make their predictions. I believe NOAA’s
own algorithms should be the most accurate, because weather and its prediction is their sole purpose. www.Weather.GOV is NOAA’s direct source for
weather information, but it takes some
study to learn how to use the site. www.
NOAA.GOV is easier to use: along the
left side of its home page, enter the city/
state of interest to go to an easier-toread forecast direct from NOAA.
Appliances, such as new models from
GE, can automatically adjust their energy consumption based on price-signals
from your energy utility. At least one
company’s washer and dryer will send
you a text or e-mail to let you know
the load is finished. GE, LG, Kenmore,
and others have brought networked
appliances to market.
Home Toys (www.Hometoys.com) is
a home technology emagazine and library that is a news and information resource for home technology—articles,
news stories, companies, products,
services, links, and so on.
Gesturing, with or without a remote
in hand, to control devices is moving
beyond gaming, but not as quickly as it
was integrated into home gaming.
DeLorme
(www.DeLorme.com)
Earthmate PN-60W GPS (Photo 15)
with SPOT satellite text messaging
capability enables limited communications when your cellphone has no service. This GPS, designed for off-road
audioXpress 6/11
Weinberg611.indd 42
travelers and hikers, literally can be a
lifesaver in an emergency.
Spot Connect and related models
(www.FindMeSpot.com; $170+) are
palm-sized packages plus service that
turn your smartphone into a satellite
communicator, not only for general
messaging, but when you need help.
They are especially useful to those who
hike in the mountains or sail most of
the seven seas, leaving you without cellphone coverage.
Toyota’s Entune multimedia system
(www.Toyota.com/entune) is an app
for your smartphone that integrates
its functions with certain new Toyota
models. It supports touchscreen and
voice commands.
Oxygen Audio (www.OxygenAudio.
com) has an “O” series of products
(such as the O’Car) designed to integrate the iPhone into your car entertainment system, providing access to
all iPhone capabilities and content via
Bluetooth and hands-free operation.
There are individuals who would like
to monitor their car’s performance
and tune its engine, but are stymied by
lack of access to the car’s computer.
iTSX (www.SCT-iTSX.com) enables
you to do so, on limited brands and
models (currently 1996-2011 Ford/
GM vehicles), by plugging into your
car’s OBD-II computer interface and
using an app on your iPod Touch,
iPhone, or iPad. CEO/president Rick
Trudo said the price likely would be
around $350-400.
PHOTO 15: Delorme Earthmate PN-60W.
5/10/2011 2:31:54 PM
exhibitor was Reese’s (www.Hersheys.
com/reeses.aspx), the peanut-butter cup
people, with the added drama of a countdown timer until they announced their
new Minis peanut-butter cups, which are
not individually paper-cup wrapped.
Another unexpected exhibitor was
Trojan (www.TrojanCondoms.com),
which, with their line of battery-operated products to “turn on the pleasure” brings them into the consumer
electronics category.
PHOTO 16: Pivot Power.
Wrap-Up
Victorinox (www.Victorinox.com)
has expanded their Presentation Master and Secure lines of pocket tools
with detachable USB memory modules
featuring biometric (finger-tip scanning) security. The Secure SSD boasts
a 256GB solid-state drive. Each series
includes models with blades, and TSAapproved flight models without blades.
Prices vary depending on configuration
and size of the memory module.
Quirky (www.Quirky.com) is a testament to entrepreneurism. Founder/
CEO Ben Kaufman has created a company that helps people with imaginative
product ideas bring them to market,
and sells them through the Quirky
website, which currently lists 74 unusual items including Pivot Power (Photo
16, an extension cord with outlets,
each of which twists/bends for space
and wall-wart connections), an iPad
lapdesk, the Shovel Master two-handle
snow shovel, the Cable Collar cord
concealer, Scratch-n-Scroll mousepad
you can write erasable notes on, the
DigiDude compact adjustable desktop
tripod/keychain, and the under-desk
Plug Hub to organize and hide a multiple power-cord outlet strip. This is a
site worth keeping an eye on.
Access Computer Products (www.
AccessRecycling.com) buys and accepts computer components, peripherals, and cellphones for recycling.
They appear to prefer pallet-sized
batches from corporate sources rather than individual products from private citizens.
DP Electronic Recycling (www.DPECycle.com) claims to be a full-service
electronic recycling company helping
businesses and individuals dispose of
electronic devices in accordance with
various federal and local laws and regulations. Their offerings include a retail/
wholesale purchasing outlet for sale
and purchase of used and refurbished
electronic gear.
Certainly the most unexpected CES
CES offered hints of things to come,
some of them a bit tantalizing, none of
them star-bright exciting.
Entrepreneurial efforts like Quirky
deserve continued attention, and I plan
to give it its due.
The iWorld supernova couldn’t be ignored anywhere in the civilized world,
nor should it be, because it can facilitate
user capabilities that science fiction writers wish they had dreamed of years ago.
Meanwhile, as we enjoy our toys and
consider which new ones to buy, I recover from the January parties and look
forward to next year’s festivities. aX
Contributors
David A. Rich (“Music Lovers Guide to Using Blu-Ray,” p. 31, and “Learning to Speak
Multichannel,” p. 34) received his MSEE from Columbia University and his Ph.D. from
Polytechnic University of NYU. He specializes in the design of analog and mixed-signal
integrated circuits and has taught graduate and undergraduate courses in integrated
electronics and electroacoustics. Student work under his guidance, including a novel
high-efficiency mixed-signal integrated power amplifier, has won numerous awards.
His industrial positions include Technical Manager at Bell Laboratories. His portfolio
has spanned the design of audio ICs for Air Force One to RF ICs for wireless cell
phones, and his innovations have earned 14 patents. He is a Senior Member of the
IEEE and has frequently served as chairperson for technical and panel sessions at
IEEE conferences. He has been a member of the AES signal processing technical
committee and has been Technical Editor for Audio Critic. He is the head of the
music committee of the Bethlehem Chamber Music Society.
David J. Weinberg (“Annual Consumer Electronics Parties,” p. 36) is an engineering
consultant and technical journalist on audio, video, and film technology. He provides
audio and home theater engineering consultation and professional on-location digital
audio recording services to companies, radio stations, and individuals. He brings
to his work an MSEE, a First Class Radiotelephone license, and over 40 years of
continued study and active involvement in the audio, video, and computer industries.
He is Chair of the Audio Engineering Society’s DC section, and a manager in the
Society of Motion Picture and Television Engineers’ DC section. David has authored
articles on various phases of audio for video and film, and serves as Membership
Officer for the Boston Audio Society (www.BostonAudioSociety.org) and Editor of its
journal: The B A S Speaker.
Weinberg611.indd 43
43
5/10/2011 2:31:55 PM
4/27/2011 2:50:27 PM
Parts Express stocks the finest yet
most affordable components and tools
required to complete your next speaker
design. Visit us online today to receive
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With over 15,000+ items, we truly have
everything but the music for all your
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parts-express.com/axm
Cabinets
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725 Pleasant Valley Dr.
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Tel: 800-338-0531
Measurement
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SPEAKER TESTING WITH DIY ACCELEROMETER

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