Product Review -
AudioControl BijouTM THX®
Equalizer - January, 1997
By Stacey Spears
Click to see larger photo |
AudioControl Bijou Home THX Room
Equalizer; Seven channel equalizer; Left front, right front,
center, left sub, right sub, left surround, right surround;
Frequency response 20 Hz - 20 kHz plus 0, minus .25dB; Harmonic
distortion 0.01%; S/N 109 dB; Maximum output 6 Vrms; Size
4.75"H x 17"W x 11"D; Weight 12 pounds; $995;
AudioControl, 22410 70th Avenue West, Mountlake Terrace,
Washington 98043; Phone (206)-775-8461, Fax (206)-778-3166;
WWW: http://www.audiocontrol.com
Introduction (The Standard Equalizer Intro)
*** Warning *** Equalizers ("EQ") are not the
"end-all, save-all solution." Care should be taken in
proper speaker placement and room treatment before ANY
equalization is performed. Remember EQ's are intended to help
provide a flat response from your loudspeakers, NOT to redesign
the them. Now that I have said that, I can begin.
I have never been on the 'Anti-EQ' front. My point of view is
that if both the film and recording industry can and do use EQ's
to correct for small problems, why can't I? The problem lies not
in the EQ but in the way in which it is used. Whenever I visit
the home of someone who owns an audio system with an EQ, the EQ
controls usually resemble a V pattern: the low and high
frequencies are boosted and the midrange is cut. When I ask them
why they have it set that way, the response is, "That is how
it is supposed to look." Look? I end up playing some music
for them, then during the middle, I hit bypass and they are
usually shocked at how much better it sounds with the EQ off.
They have never listened to it this way because out of the box
they adjust the EQ and never listen to any other way. Of course,
not all of them like the change when I bypass the EQ. They prefer
their system to sound like a mini truck! "Boom, Boom,
Boom." The problems represent an improper use of the EQ, due
to lack of experience and or test equipment to properly set them
up, and secondly, most EQ's that come with rack systems are poor
in quality, killing the signal as it passes through.
Enter AudioControl
AudioControl has been building high quality EQ's and Analyzers
since 1977. They know that in the high-end world of audio that if
their products do anything harmful to the audio signal, then they
won't sell. The Bijou is the second Home THX Equalizer to come to
market. It is the first THX EQ to be equipped with surround
channel equalization, and it is also the first consumer EQ to
have 1/6th octave control for the subwoofer channel. Other
features of the Bijou include:
- Constant-Q: Without being too techy in description, this insures that when you adjust a single band on the EQ, you are ONLY adjusting that band and not the adjacent bands with it.
- Security Cover: It is an option, but is a must have. Once the EQ is set, just place the cover on the unit, and you will not have to worry about OTHER people playing with the sliders.
- DB 25 Connections: These are available on both the input and output, and are very handy if you want a clean wiring job and want to insure you make no mistakes on hookup.
The layout of the Bijou is as follows: There are 11 bands in 1/3
octave intervals for each of the Left, Center, and Right channels
from 80 Hz to 800 Hz. The Left and Right surround channels each
consist of 8 bands in 2/3 octave intervals from 100 Hz to 6.3
kHz. There are 12 bands in 1/6 octave intervals for the subwoofer
(one set for two sub's). Also located on the front is the Power
On/Off button and the EQ bypass button. On the back are 7 RCA
connectors for input and 7 RCA connectors for output. There are
also 2 DB-25 jacks, one for input and one for output. Lastly,
there are a 200 Watt unswitched outlet and a non-detachable power
cord.
The Installation
Over the past few months, I have had the Bijou in two systems:
One (System A) has 4 full range speakers (Front L/R,
Surround L/R), a smaller Center Channel and a powered subwoofer.
The other (System B) is a full THX speaker package, 3
identical L/C/R, 2 Dipolar surround speakers and a subwoofer. In
both installations I used a THX certified surround processor and
a THX certified 6 Channel Amplifier. System A is optimized for
both Music and Film and is equipped with AC-3, while System B is
strictly for film with no AC-3.
System A: I used 3 pairs of interconnect cables from the
Surround Processor to the Bijou and 3 more pair from the Bijou to
the power amplifier. The real problem when using an EQ is that
you must have double the normal interconnects. With a 2 channel
music system this only requires one more pair, but with home
theater you will need 3. This can really hurt the pocket book
with "Audiophile" cables. DB-25 cables are available
from any computer supply store or catalog, for less than $10
each. I am sure that high end audio DB-25s will be available
shortly from numerous audio manufacturers.
System B: I used 3 pairs of interconnect cables from the
Surround Processor to the Bijou, and 1 Monster DB-25 cable from
the Bijou to the Amplifier. Since the surround processor is not
equipped with DB-25 output I have had to use separate cables.
Since the Bijou has them, this allowed me to use the amplifier's
DB-25 input. I think this was a really cool way to go: 1 big
cable, very little wire mess. One note, my power amplifier
"only" provides 6 channels, and the Bijou can pass 7
channels through the DB-25, two subs sharing a common ground. If
I were to use two subs I would have needed an additional cable
(either running to a separate amp or a powered sub) along with
the DB-25 terminated cable.
Now that the hookup is complete, the fun part can begin.
Calibration, while not that difficult, is VERY time consuming.
The instruction manual, or Owners Enjoyment Manual as
AudioControls calls it, is very easy to understand and gets you
going very quickly. The manual is a general overview of the
calibration process, and therefore I recommend obtaining the
"Home THX Audio System Room Equalization Manual." I
contacted the THX division through their home page and within a
week I had the latest version of the manual. This manual goes
into detail with examples on how to fine tune your EQ.
To get started properly you will need a Real Time Spectrum
Analyzer. I use the AudioControl SA-3050A RTA which has all the
requirements needed to properly setup an EQ and is very
affordable. I also used my trusty old Radio Shack SPL meter, a
microphone stand, some masking tape (to mark the spots where you
place your mic stand), and a pink noise source. The SA-3050A is
equipped with a generator, but I used the THX WOW disc for this
(Chapters 8-11).
There are a few settings on your RTA that must be correct before
you begin:
- "dB Per Step" to 2
- "Speed" or "Averaging" to Slow
- "Volume" at reference level
- REMOVE any Weighting (i.e. 'C' or 'A')
The actual installation in each system took a few hours. It
consisted of measuring, adjusting, and then re-measuring. The
utmost care should be taken to ensure that you do not go crazy
with the sliders. You want to make the adjustments as little as
possible. A 1 or 2 dB variation between frequencies is ok.
There were some variations for setup that I used between the two
systems:
System A: I used stereo mode for setting up all the
channels. I had to do some interconnect swapping (I used the main
Left and Right outputs) for the surrounds and again for the
center and subwoofer. This was done because Pro-Logic limits the
information in the surround channels, and AC-3 is capable of full
range for all 5 channels. The main and surround Left and Right
speakers were full range and the Center was cut off at 80 Hz
through the control of the surround processor. I used the
Subwoofer to help with the center and also as the .1 channel for
AC-3.
System B: This was the ideal setup for the Bijou. The
Subwoofer handled all of the information below 80 Hz, and the
Left, Center, and Right dealt with information above 80 Hz. The
surround speakers were THX dipolar. I did all the measurements in
Pro-Logic mode. Since the processor was not capable of AC-3, I
was not worried about full bandwidth measurements in the surround
channels. Eventually when AC-3 is added to System B, I will still
be using the dipolar speakers. I will just ensure that bass
management is properly being used, and the Bijou will still be
good-to-go.
The Bijou in Action
The Bijou is compatible with AC-3 since it allows for separate
adjustments for all the channels. It just does not cover the full
spectrum for every channel. Just like the Rialto reviewed in
November 1995, it is optimum for Pro Logic/THX, and not AC-3.
Most of the problems I encountered were in the 100 Hz - 1 kHz
range, so this unit does work for AC-3, but it is just not ideal.
I would like to have seen 5 channels in 11 bands of 1/3 octave
instead of the 3.
System A: With the front speakers, all of the
corrections were only necessary and possible in the 80 Hz to 800
Hz range, and everything was virtually flat above 1 kHz. The
surround channels were a little trickier to work with since I
only had half the bands. There were a couple of bumps that I
could not get to, but in the end, the improvements were very
noticeable. My center channel was a different make than the left
and right speakers, and using the Bijou, I was able to bring them
a little closer together (tonality). There was also better dialog
intelligibility all around. I was also able to improve the tonal
balance across the entire front, where the TV normally messes
things up (reflections off the face of the picture tube from the
center channel speaker output).
System B: This system integrated with the Bijou much
better. I followed the THX approach to the 'T'. I was able to
dial in all 5 channels, with very little trouble. The Bijou
really shined here; again dialog intelligibility was improved and
I was able to correct for the TV's tonal effect on the center
channel.
The 12 band 1/6 octave control over the subwoofer was really
powerful. There was one major problem however, and that was the
limit of the 1/3 octave analyzer; I wish a had a 1/6 octave
analyzer. :-) I was in complete control when it came to the
subwoofer. Bass was now tighter and more defined. The EQ has the
ability to control 2 subwoofers with the 12 bands, but I only had
one sub on hand at the time of the review.
There was no noticeable noise or hiss when the EQ was switched in
(no music playing). I really had to press my ear against the
speaker to hear anything. As with all EQ's, you have unavoidable
phase shift, but since all channels are passing through the EQ
there were no noticeable effects.
There is no better audio feeling than being able to sit down and
listen to music or watch a film and forget about the actual
hardware that is providing it for you. With the new release of,
"The King and I", it was really nice to have characters
walk from one side of the screen to the other and not have the
tonal character of their voice change as they moved. Even with
three perfectly matched speakers (as in System B), this was not
possible without proper equalization, because of the different
boundaries surrounding each speaker.
Conclusion
I found that proper equalization provided by the Bijou has added
new depth to my listening systems. I was able to better control
System B because of the way in which that system was configured.
System A benefited as well; I just did not have as much control
as I would have liked. If you are looking to extract the most
from your home theater system, then I recommend you give the
Bijou a test drive.
Stacey Spears
© Copyright 1995, 1996, 1997 Secrets of Home
Theater & High Fidelity
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