ACI AWS Owners manual

AWS Setup

The AWS ( Adaptive Woofer System) is a powerful tool that enables you to get optimum
sound performance from your ACI speaker system. AWS allows you to tune the speaker
to your room and placement. The instructions for using AWS are presented in the
manual and on the CD.

1. The Purpose of Equalization

2. Using the AWS Controls

3. Measurement and Adjustment Methods

4. Adjusting AWS using a Radio Shack SPL Meter and AWS Spreadsheet

5. Adjusting AWS using a Radio Shack SPL Meter and Graph Paper

6. Alternative Means of Measurement and Equalization

7. Website based updates

8. Supplemental Materials:
AWS Excel Spreadsheet
Printable Graph for Hand Plotting
Praxis Files
Trueaudio RTA Audio Analyzer Information

Audio Concepts, Inc.

901 South 4th Street, La Crosse, WI 54601

Phone: [phone] Fax: [phone]

Website: www.audioc.com Email: [e-mail]

All Rights Reserved 2002

Sound that Satisfies…

1. Purpose of Equalization

Most of us listen to our speakers in less than ideal conditions. Typical

rooms are rectangles or at least rooms with some parallel walls. Most rooms
have a great number of standing waves that interact with the original signal,
either constructively or destructively . An example of a constructive interaction is
when the standing wave is in phase with the original signal, resulting in a peak at
a given frequency. Destructive interaction is when the signal is out of phase with
the original signal, resulting in a dip of the frequency.

A standing wave occurs when the distance between two walls is equal to

half the length of the wavelength. This effect is seen throughout the whole
frequency range. So why should we equalize the bass and ignore the standing
waves at higher frequencies? First, it is much easier to treat higher frequencies
with room treatments. Carpet, rugs, plants, and furniture do a fairly good job at
absorbing and dispersing higher frequencies. Lower frequencies are quite a bit
more difficult to absorb. For example, given a 40 Hz wave, it would take seven
feet, (1/4 wavelength) of absorbing material to reduce a reflection of that
particular wave. At 2KHz, it would only take about an inch and a half of
absorbing material. Our ears average the midrange and high frequencies for us.
We don’t hear each individual peak or dip. It would be extremely difficult to
equalize the huge number of peaks and dips in the midrange and high
frequencies.

Bass is a different story, in most domestic listening spaces there will be

one or two dominant resonant peaks in the bass response. These are the bass
notes that just jump out at you, that cause that excessive “boom”. These notes
hang on long after they should stop. These resonances often cause the entire
bass range to sound “slow” or bloated. Audiophiles have often dealt with this by
using speakers with a very lean bass or turning their subwoofers way down.
However, it is possible to have powerful and accurate bass response if we can
significantly reduce the amplitude of these major peaks. This is one of the two
major functions of what the AWS is designed to do.

AWS is also designed to give you the power to control the tonal balance of

the speaker. The perceived tonal balance of a speaker will change depending on
its placement within the room. Placing the speaker closer to room boundaries or
large furniture increases bass output. These boundaries act much like a mirror
behind a light bulb focusing the energy. An example would be a stand mounted
Veritas vs. a Veritas that is mounted flush in a large entertainment center. The
Veritas mounted in the entertainment center will have a bass heavy balance
compared to the stand mounted Veritas. The bass volume control in the AWS will
easily adjust for either placement.

What about dips or
holes in the bass response?
Missing information is far less
objectionable than too much
information. Our ears tend to
fill in missing information so it
sounds “right”. This is a good
thing because an equalizer is
not effective at filling in holes
in the response. If fact, trying
to add a lot of boost to one
part of the spectrum will
usually result only in
increased distortion and
possible woofer damage. We
do not recommend using the
AWS to boost parts of the
response. It is far more
effective to reduce the peaks
to get a smoother overall
response.

2. Using the AWS Controls

There are two sections to the EQ controls. The first section is preset at the
factory. The High pass frequency and Phase control should be left at the factory
settings. The Volume control may be adjusted up or down to compensate for
speaker placement and desired total balance. Test tones are provided to
calibrate the volume level to neutral in your setting. Adding additional bass
volume beyond neutral will give the system a warmer overall balance.
Decreasing the bass level below neutral will result in a leaner balance with more
perceived detail.

The second section includes the two parametric EQ controls. There are three
adjustments and in/out switches for each band. The Gain controls the amount of
volume you want to subtract or add. The Frequency selection control adjusts the
frequency you are trying to alter. The Q control adjusts the width of the band. The
in/out control turns the particular EQ section on or off.

Note the Gain control has adjustable range from –9 to +6. It should be noted that
trying to fill in holes should generally be avoided. It is usually better to play
around with speaker/ listener placement to avoid dips. Increased distortion and
dynamic limitation are usually the only things gained by trying to fill in response
dips.

3. Measurement and Adjustment Methods

1. By Ear: Recommended only for those who are very brave and possess well-

trained ears. Certainly you can use the test tones to spot frequencies that
sound to loud in relation to the other frequencies, but it will be difficult.

2. Using the Radio Shack SPL meter and AWS
Excel spreadsheet: This method is relatively easy,

inexpensive, and quite accurate. It can be rather time
consuming compared to methods four or five.

3. Using the Radio Shack SPL meter and hand
plotted graphs: Very similar to #2 but you'll have to do

a little math when hand plotting.

4. Using a test system such as ETF, CLIO or
MLSSA: If you have this type of equipment you can run

the measurements quickly and accurately. Usually the
most expensive option. Most of these instruments are extremely powerful and
can have a relatively steep learning curve. Separate measurement
microphone and possibly microphone pre-amp will also be required.

5. Using a RTA (Real Time Analyzer): This is probably the fastest method as
you can see the results of your adjustments on-screen, in real time. RTAs

used to be quite expensive. Computers with soundcards have drastically
changed that! The CD contains a free Demo version of Praxis, which is an
extremely powerful RTA and more. We also provide a link to the relatively
inexpensive, powerful and easy to use RTAs by TrueAudio. Separate
measurement microphone and possibly a microphone pre-amp will also be
required.

4. Using the Radio Shack SPL meter and AWS Excel spreadsheet
Radio Shack Cat No. 33-2050

Sine waves were chosen for EQ setup because of their ease of use, accuracy of
the results, and simplicity.

Please follow the directions below for setting your EQ:

1. The volume control of your speaker system was calibrated to a
nominally "flat" balance at the factory. Depending on your room and
placement, you may need to adjust the relative level of the bass
drivers.

2. Insert the test disc in your CD player. Position the SPL meter at
approximate listening position. The meter should be aimed toward the