VOCE AV5.1K AMPLIFIER AND AV BIT IN

R
t e S t
e p o r
t
Voce AV5.1K Amplifier and AV bit IN
Amplifier Review
W o r d s a n d M e a s u r e m e n t s b y G a r r y S p r i n gg a y
n 1979, in the Marche region of Italy between the Apennines and the
Adriatic, a group of technicians who shared a passion for high-fidelity
music banded together to form a company now known worldwide as Audison.
The name “Audison” is from the Latin words “audio” and “sonus” and represents both the
historic roots and general philosophy of the company. Since its inception, the Audison brand
has earned a solid reputation for designing and building very high-quality, high-performance
car audio products, many of which incorporate leading-edge technologies.
I
Over the years, Audison has been the
recipient of many prestigious awards and
accolades that celebrate, primarily, its passion for music and no-nonsense approach
to the engineering of its products. And, while
generally not the most economical products
available, the Audison brand of mobile audio
gear has always stood for high-quality and
excellent performance.
In this review, Cogent Audio Labs takes a
close look at Audison’s Voce AV5.1K amplifier and the Voce AV bit IN digital interface.
With a suggested retail price of $1,650
for the amplifier and $180 for the digital
interface, one would figure these are serious
pieces of audio gear. Well, indeed they are
68
Performance Auto & Sound
and; because the Voce series is a direct
descendant of the exceptional Thesis series,
they now bring the legendary Thesis sound
quality to a wider range of enthusiasts. And,
like the Thesis products, the Voce series also
has the ability to combine analog and digital
technologies.
› features
The Voce AV5.1K is a five-channel amplifier designed to be the only amp you’ll
need for your entire system. It has a rather
unusual configuration in that the front
and rear class AB channels have differing
power levels – the rated power for the front
channels is listed at 75 W per channel and
The Voce AV5.1K is a
five-channel amplifier
designed to be the only
amp you’ll need for your
entire system
the rear channels are rated at 140 W into
four ohms and 250 W into two ohms. The
subwoofer channel has a 600-watt rating
at four ohms and a 1,000-watt rating into a
two-ohm load.
Here’s another Italian twist... In an effort
to provide the absolute best possible sound
quality, the front channels are designed to
be used only with four-ohm loads whereas
the rear channels can drive two- or fourohm loads.
On one end of the amplifier you find the
input section with both high-level and RCA
connections available. And, there’s even
a method of obtaining a RCA-level signal
output from the high-level inputs through
Amplifier Review
the use of a built-in high- to low-level
convertor. The amp can be configured
to turn on with a traditional 12 V trigger
signal or by using the audio signal,
which is very handy in certain vehicles
that don’t have a traditional trigger
output.
At the opposite end of the amplifier
are all the power and speaker terminals, which will accept four and eight
gauge cables, respectively. A second B+
terminal is provided for the connection of an external super capacitor.
Also found here is a connection for
the optional VCRA subwoofer volume
control as well as the 12 V trigger input
and output.
Under a pair of removable acrylic
panels on top of the AV5.1K are the
crossover controls, which are also a
bit unusual. The front channels can be
configured in either full range mode
or in high pass mode with a frequency
adjustment range from 50 Hz to 5
kHz. The rear channels have settings
for full range, high pass or band-pass
modes. The high pass filter section has
a frequency range of 50 Hz to one kHz
and the low pass section is adjustable
from 250 Hz to 5 kHz. Front and rear
crossovers use a -12 db per octave
slope. The subwoofer crossover can be
set between 50 Hz and 150 Hz with a
-24 dB per octave slope. Setting the
subwoofer channel to full range pro-
70
Audison Voce AV5.1K Amplifier and AV bit IN
MEASURED
PERFORMANCE
SPECIFICATIONS
Manufacturers
Rated Power
75 W x 2 @ 4 Ω
+ 140 W x 2 @ 4 Ω
+ 600 W x 1 @ 4 Ω
75 W x 2 @ 4 Ω
+ 250 W x 2 @ 2 Ω
+ 1,000 W x 1 @ 2 Ω
Actual Measured
Power
@ 1.0% THD+N
@ 12.6V Battery
77 W x 2 @ 4 Ω
+ 124 W x 2 @ 4 Ω
+ 609 W x 1 @ 4 Ω
77 W x 2 @ 4 Ω
+ 191 W x 2 @ 2 Ω
+ 847 W x 1 @ 2 Ω
Actual Measured
Power
@ 1.0% THD+N
@ 14.4V Battery
97 W x 2 @ 4 Ω
+155 W x 2 @ 4 Ω
+757 W x 1 @ 4 Ω
97 W x 2 @ 4 Ω
+250 W x 2 @ 2 Ω
+1,066 W x 1 @ 2 Ω
Performance Auto & Sound
vides useful output at up to about 1.5 kHz. The amplifiers gain controls
are also top-mounted, but are accessible at all times.
Under the opposing acrylic panel is the amplifier’s main power fuse,
a 100-ampere mini-ANL. There are several other things that set the
AV5.1K apart from other five-channel amplifiers. These include the way
the front channels are biased for maximum fidelity as well as how the
Amplifier Management Processor (AMP) continually monitors the operational condition of the amp and communicates the condition to the user
via four different color LEDs.
But, what really sets this amplifier apart from everything else is its
ability to transform from a typical analog input amp to a full digital input
amplifier.
The advantages of using digital signal transfer between components
in a car are significant. First of all, by sending a digital bitstream of data
you automatically eliminate the possibility of radiated noise issues entering your signal cables, which is a major source of complaint for many
people. Second, the digital signal provides optimal signal-to-noise and
dynamic range in the audio signal and these benefits can be easily heard
by even an untrained listener.
To use the AV5.1K in full digital mode, you simply remove two screws,
gently pull out the analog input module and replace it with the AV bit
IN digital module. The change is very simple and takes less than five
minutes to accomplish.
To feed the fully digital AV bit IN module, you need an Audison bit One
or bit Ten D processor with the connections done via a conventional
CAT5 Ethernet cable and a RJ-12 cable. Setup of the channel addressing
is straightforward and takes only a few seconds. The digital audio bus is
capable of carrying a signal for up to eight channels.
› Listening
For my critical listening evaluations of these products, I decide to
drive only three of the five channels. I connect the ultra high fidelity
front channels to my reference speakers and the subwoofer channel
to a high-quality 12-inch woofer in a sealed enclosure. I first listen to
the amplifier in analog mode and, as with every other Audison product
Amplifier Review
I have ever heard, I’m not disappointed. The sonics of the amplifier
are very good with excellent timbre
and great detail in the top end. The
amp sounds very neutral in terms of
coloration and it creates a very good
stereo image.
Regardless of my music choice,
I’m generally very happy with the
sonic performance of the AV5.1K.
Occasionally, I note the woofer’s
output is perhaps slightly muddier
than I had expected, but I only notice
this on difficult and dynamic tracks
that I’ve literally heard thousands of
times. The average critical listener
would probably never even notice.
Another thing I notice is this amp
isn’t shy about pulling some current.
Even with the rear channels unused,
I see peaks of 50 and 60 amperes of
current draw at moderate volumes.
After a couple hours of listening
to some of my favorite evaluation
tracks, I add a bit One and the AV bit
IN to the system. To get the maximum benefit from the all-digital
signal path, I feed the input of the
bit One with the SPDIF output from
my CD player. The difference in dynamic range and realism is startling.
In this mode, the same music has
improved realism, depth and seems
more exciting to listen to.
Just to see what would happen,
I switch to an analog input on the
bit One and noted that the change
has caused a noticeable loss in
dynamics and lacks some of the
Audison Voce AV5.1K Amplifier and AV bit IN
4 ohm power vs THD 100Hz 14.4V Batt
Cogent Audio Labs
%
Cogent Audio Labs
10
5
5
2
2
1
1
0.5
0.5
0.2
0.2
0.1
%
0.05
0.02
0.02
0.01
0.01
0.005
0.005
0.002
4 OHM POWER vs THD 100Hz 12.6V Batt
The following power measurements have been obtained using industry standard methods
(1 kHz @ 1.0% THD+N – Battery voltages shown +/- 0.2 V).
Signal to Noise Ratio referenced to 2 V output (CEA-2006A) (1 W @ 4 Ω)
Signal to Noise Ratio referenced to full output
0.1
0.05
0.001
TECHNICAL DATA
4 ohm power vs THD 100Hz 12.6V Batt
4 OHM POWER vs THD 100Hz 14.4V Batt
10
0.002
600m
1
2
5
10
20
50
100
200
500
1k
2k
0.001
5k
600m
1
2
5
10
20
W
AV 5.1K
Blue Trace Front // Red Trace Rear // Magenta Trace Sub
4 OHM POWER vs THD
50
100
200
500
1k
2k
5k
W
100Hz
14.4V Batt
AV 5.1K
Blue Trace Front // Red Trace Rear // Magenta Trace Sub
4 OHM POWER vs THD
100Hz
12.6V Batt
THD+N at rated 4 Ω power
Maximum Efficiency at full 4 Ω power per ch.
Maximum Efficiency at full 2 Ω power per ch.
Idle Current
Input Sensitivity
Maximum Current at full power, lowest rated impedance
Frequency Response (-3 dB)
High Pass Crossover
Max Flat - Frequency Response
Cogent Audio Labs
Low Pass Crossover
Crossover Range - Frequency Response
MAX FLAT - FREQUENCY RESPONSE
Cogent Audio Labs
+6
Sub Channel Crossover
CROSSOVER RANGE - FREQUENCY RESPONSE
+6
+5.5
Subsonic Filter
Bass EQ boost
+4
+5
+2
+4.5
-0
+4
+3.5
-77.7 dBA F/R
-67.2 dBA Sub
-99.6 dBA F/R
-96.0 dBA Sub
0.07%
64.2%
61.4%
3.0 A
308 mV – 5.2 V
199 A
<10 Hz – 62 kHz
50 Hz – 5 kHz
-12 dB/Oct
250 Hz – 5 kHz
-12 dB/Octz
50 Hz – 150 Hz
-24 dB/Oct
None
None
-2
+3
-4
+2.5
-6
+2
+1.5
-8
+1
-10
+0.5
d
B
r
d
B
r
-0
-0.5
-12
-14
-1
-16
-1.5
-18
-2
-20
-2.5
-22
-3
-24
-3.5
-4
-26
-4.5
-28
-5
-30
-5.5
-6
10
20
50
100
200
500
1k
2k
5k
10k
20k
30k
-32
10
20
Hz
AV 5.1K
MAX FLAT -- FREQUENCY RESPONSE
AV 5.1K
Sub CH Crossover Range - Frequency Response
Cogent Audio Labs
50
100
200
500
1k
2k
Hz
Ref - 2.0Vrms 4 ohm load
SUB CH CROSSOVER RANGE - FREQUENCY RESPONSE
+6
+4
+2
-0
-2
REAR CHANNELS CROSSOVER RANGE -- FREQUENCY RESPONSE
Ref - 2.0Vrms 4 ohm load
5k
10k
20k
30k
realism the full digital path has provided. I’d say it’s 80% as good as the full digital mode
– certainly better than the analog-only path. No question, full digital is the way to go if
you have a digital source.
For those of you wondering how to get a digital audio source in your car, there are
several companies who build products that connect to an Apple or other device. This approach allows you to bypass the player’s limited quality on-board DAC and provide a fully
digital signal via SPDIF or digital coaxial outputs, which can then be fed directly into the
bit One or bit Ten D. Some of these digital adapters are actually designed for home use,
so they need some tweaking to work in your car, but many have had good success with
the Logitech Squeezebox Touch and the Pure i-20 dock among others.
Rumor has it that Audison is also working on a high definition music player of its own
tentatively called bit Play. That’s something else to keep an eye open for.
-4
-6
› PERFORMANCE / BENCH MEASUREMENTS
-8
-10
-12
-14
d
B
r
-16
-18
-20
-22
-24
-26
-28
-30
-32
-34
-36
-38
-40
10
20
50
100
200
500
1k
2k
Hz
AV 5.1K
SUB CHANNEL CROSSOVER RANGE -- FREQUENCY RESPONSE
Ref - 2.0Vrms 4 ohm load
5k
10k
20k
30k
The five-channel Audison amplifier measures well on the test bench. Frequency
response is excellent and the amplifier easily exceeds every one of its published power
numbers. Distortion measures very low, especially on the over-biased front audiophilestyle channels. My concerns about current draw are confirmed when I blew the 100-ampere fuse doing my two-ohm maximum power tests. Not to worry. Under normal use
when listening to music this will never be a problem, but it does show how much current
the amp can draw when pushed to its considerable upper limits. To maximize the performance and enjoyment from an amp as good as this, I strongly suggest you use topquality pure copper cables and you may want to take advantage of the terminal provided
for the external super capacitor as well.
› CONCLUSION
The Audison AV5.1K amplifier is another great piece of audio gear from a company that
clearly cares about sound. The ability to incorporate a full digital front end is simply icing
on the cake and after tasting it, it’s icing I wouldn’t do without.
If you are serious about your sound quality and don’t mind spending a few extra bucks
for a quality product that will undoubtedly provide many years of enjoyment, the Audison
AV5.1K and the bit IN should be on your short list of equipment to audition. PAS
For additional photos and exclusive video, visit pasmag.com/AudisonVoceAV
> audison.com
72
Performance Auto & Sound
> elettromedia-usa.com
Amplifier Review
I have ever heard, I’m not disappointed. The sonics of the amplifier
are very good with excellent timbre
and great detail in the top end. The
amp sounds very neutral in terms of
coloration and it creates a very good
stereo image.
Regardless of my music choice,
I’m generally very happy with the
sonic performance of the AV5.1K.
Occasionally, I note the woofer’s
output is perhaps slightly muddier
than I had expected, but I only notice
this on difficult and dynamic tracks
that I’ve literally heard thousands of
times. The average critical listener
would probably never even notice.
Another thing I notice is this amp
isn’t shy about pulling some current.
Even with the rear channels unused,
I see peaks of 50 and 60 amperes of
current draw at moderate volumes.
After a couple hours of listening
to some of my favorite evaluation
tracks, I add a bit One and the AV bit
IN to the system. To get the maximum benefit from the all-digital
signal path, I feed the input of the
bit One with the SPDIF output from
my CD player. The difference in dynamic range and realism is startling.
In this mode, the same music has
improved realism, depth and seems
more exciting to listen to.
Just to see what would happen,
I switch to an analog input on the
bit One and noted that the change
has caused a noticeable loss in
dynamics and lacks some of the
Audison Voce AV5.1K Amplifier and AV bit IN
4 ohm power vs THD 100Hz 14.4V Batt
Cogent Audio Labs
%
Cogent Audio Labs
10
5
5
2
2
1
1
0.5
0.5
0.2
0.2
0.1
%
0.05
0.02
0.02
0.01
0.01
0.005
0.005
0.002
4 OHM POWER vs THD 100Hz 12.6V Batt
The following power measurements have been obtained using industry standard methods
(1 kHz @ 1.0% THD+N – Battery voltages shown +/- 0.2 V).
Signal to Noise Ratio referenced to 2 V output (CEA-2006A) (1 W @ 4 Ω)
Signal to Noise Ratio referenced to full output
0.1
0.05
0.001
TECHNICAL DATA
4 ohm power vs THD 100Hz 12.6V Batt
4 OHM POWER vs THD 100Hz 14.4V Batt
10
0.002
600m
1
2
5
10
20
50
100
200
500
1k
2k
0.001
5k
600m
1
2
5
10
20
W
AV 5.1K
Blue Trace Front // Red Trace Rear // Magenta Trace Sub
4 OHM POWER vs THD
50
100
200
500
1k
2k
5k
W
100Hz
14.4V Batt
AV 5.1K
Blue Trace Front // Red Trace Rear // Magenta Trace Sub
4 OHM POWER vs THD
100Hz
12.6V Batt
THD+N at rated 4 Ω power
Maximum Efficiency at full 4 Ω power per ch.
Maximum Efficiency at full 2 Ω power per ch.
Idle Current
Input Sensitivity
Maximum Current at full power, lowest rated impedance
Frequency Response (-3 dB)
High Pass Crossover
Max Flat - Frequency Response
Cogent Audio Labs
Low Pass Crossover
Crossover Range - Frequency Response
MAX FLAT - FREQUENCY RESPONSE
Cogent Audio Labs
+6
Sub Channel Crossover
CROSSOVER RANGE - FREQUENCY RESPONSE
+6
+5.5
Subsonic Filter
Bass EQ boost
+4
+5
+2
+4.5
-0
+4
+3.5
-77.7 dBA F/R
-67.2 dBA Sub
-99.6 dBA F/R
-96.0 dBA Sub
0.07%
64.2%
61.4%
3.0 A
308 mV – 5.2 V
199 A
<10 Hz – 62 kHz
50 Hz – 5 kHz
-12 dB/Oct
250 Hz – 5 kHz
-12 dB/Octz
50 Hz – 150 Hz
-24 dB/Oct
None
None
-2
+3
-4
+2.5
-6
+2
+1.5
-8
+1
-10
+0.5
d
B
r
d
B
r
-0
-0.5
-12
-14
-1
-16
-1.5
-18
-2
-20
-2.5
-22
-3
-24
-3.5
-4
-26
-4.5
-28
-5
-30
-5.5
-6
10
20
50
100
200
500
1k
2k
5k
10k
20k
30k
-32
10
20
Hz
AV 5.1K
MAX FLAT -- FREQUENCY RESPONSE
AV 5.1K
Sub CH Crossover Range - Frequency Response
Cogent Audio Labs
50
100
200
500
1k
2k
Hz
Ref - 2.0Vrms 4 ohm load
SUB CH CROSSOVER RANGE - FREQUENCY RESPONSE
+6
+4
+2
-0
-2
REAR CHANNELS CROSSOVER RANGE -- FREQUENCY RESPONSE
Ref - 2.0Vrms 4 ohm load
5k
10k
20k
30k
realism the full digital path has provided. I’d say it’s 80% as good as the full digital mode
– certainly better than the analog-only path. No question, full digital is the way to go if
you have a digital source.
For those of you wondering how to get a digital audio source in your car, there are
several companies who build products that connect to an Apple or other device. This approach allows you to bypass the player’s limited quality on-board DAC and provide a fully
digital signal via SPDIF or digital coaxial outputs, which can then be fed directly into the
bit One or bit Ten D. Some of these digital adapters are actually designed for home use,
so they need some tweaking to work in your car, but many have had good success with
the Logitech Squeezebox Touch and the Pure i-20 dock among others.
Rumor has it that Audison is also working on a high definition music player of its own
tentatively called bit Play. That’s something else to keep an eye open for.
-4
-6
› PERFORMANCE / BENCH MEASUREMENTS
-8
-10
-12
-14
d
B
r
-16
-18
-20
-22
-24
-26
-28
-30
-32
-34
-36
-38
-40
10
20
50
100
200
500
1k
2k
Hz
AV 5.1K
SUB CHANNEL CROSSOVER RANGE -- FREQUENCY RESPONSE
Ref - 2.0Vrms 4 ohm load
5k
10k
20k
30k
The five-channel Audison amplifier measures well on the test bench. Frequency
response is excellent and the amplifier easily exceeds every one of its published power
numbers. Distortion measures very low, especially on the over-biased front audiophilestyle channels. My concerns about current draw are confirmed when I blew the 100-ampere fuse doing my two-ohm maximum power tests. Not to worry. Under normal use
when listening to music this will never be a problem, but it does show how much current
the amp can draw when pushed to its considerable upper limits. To maximize the performance and enjoyment from an amp as good as this, I strongly suggest you use topquality pure copper cables and you may want to take advantage of the terminal provided
for the external super capacitor as well.
› CONCLUSION
The Audison AV5.1K amplifier is another great piece of audio gear from a company that
clearly cares about sound. The ability to incorporate a full digital front end is simply icing
on the cake and after tasting it, it’s icing I wouldn’t do without.
If you are serious about your sound quality and don’t mind spending a few extra bucks
for a quality product that will undoubtedly provide many years of enjoyment, the Audison
AV5.1K and the bit IN should be on your short list of equipment to audition. PAS
For additional photos and exclusive video, visit pasmag.com/AudisonVoceAV
> audison.com
72
Performance Auto & Sound
> elettromedia-usa.com