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sense level
+
low
peak
Power Switch & On Indicator: This switch turns power on, and is
also used to enter setup (see Setup Button & Indicator below).
Setup Button & Indicator:
adjacent indicator are used to enter setup mode. Setup mode is a
simple, automated procedure for setting the controls described
below. When setup is completed, the control settings are stored in
non-volatile memory. To enter setup mode: While the Power
Switch is turned off, press and hold the Setup Button. While
holding the Setup Button, turn the Power Switch on. Continue
holding the Setup Button until the Setup Indicator lights. When the
Setup Button is released, the Min Indicator will also light (see
Setup / dB Gain Display below). NOTE: Setup requires program
& sense signals be present. Once setup is completed, the Setup
button may be disabled (see Options on pg. 6).
Setup / dB Gain Display: This row of eight indicators serves
three purposes. During setup mode, individual indicators will light
to show the proper sequence of control adjustments. During
normal operation, the display provides gain metering. During
Bypass, the Min Level control setting is displayed (see below).
NOTE: If the Overload indicator flashes during normal operation,
reduce input signal levels and repeat the setup procedure.
Min Level: This screwdriver adjustable control determines the
minimum output gain of the ANC22 (for periods of low ambient
noise). Adjust Min Level during setup mode, only while the Min
Indicator is lit. Set the Min Level control for the program volume
which will be appropriate when background noise is the 'quietest'.
Min Level has a range of -20dB to +18dB. Once Min Level has
been set, press the Setup Button and the Sense Indicator will light
(see Sense Level & Indicators below).
Sense Level & Indicators: This screwdriver adjustable control
determines the appropriate sense input level. Initially, this control
should be increased only until the Low Indicator goes off. Once
Sense Level has been set, press the Setup Button and the Max
Indicator will light (see Max Level below). NOTE: Max Level
settings may cause the Peak Indicator to light. If so, decrease
Sense Level until the Peak Indicator goes off, then repeat the
setup procedure to store the new settings in non-volatile memory.
Once setup is completed, do not disturb the Sense Level control.
Max Level: This screwdriver adjustable control determines the
maximum output gain of the ANC22 (for periods of high ambient
noise). Adjust Max Level during Setup Mode, while the Max
Indicator is lit. Set the Max Level control for the program volume
which will be appropriate when backgound noise is the 'loudest'.
Max Level has a range from the Min Level setting to +18dB. Once
Max Level has been set, press the Setup Button and the Time
Indicator will light (see Sample Time below). NOTE: If Max Level
FRONT PANEL / SETUP
30 sec
1:1
10 sec
2.5 min
+ +
+
1 sec
5 min
1:2
2:1
min
max
sample
gain
level
level
time
ratio
This momentary push-button &
setup
sense min max time ratio
overload
3
6
9
12
18
24
32
40
dB gain
settings cause the Peak Indicator to light, decrease Sense Level
until the Peak Indicator goes off, then repeat the setup procedure
to store the new settings in non-volatile memory
Sample Time: This screwdriver adjustable control determines the
length of time the ANC22 uses to sample noise levels at the Sense
Input.
Sample Time affects how accurately the ANC22 will
calculate an 'average' noise level, as well as how quickly it will
respond with a program volume adjustment. Lower settings allow
less sampling time, but offer a quicker response time. This is good
for applications (such as subway terminals) where the ambient
noise level may change drastically within a short period of time.
Higher settings provide a longer sampling time, and a longer
response time. This is good for applications (such as restaurants)
where the ambient noise level changes gradually. A setting of '10
sec' is a good starting point for most applications. Once Sample
Time has been set, press the Setup Button and the Ratio Indicator
will light (see Gain Ratio below). NOTE: During setup of Sample
Time, the Bypass Indicator functions as a Rate Indicator, and will
flash each time a complete sampling period has elapsed (see
Bypass Switch & Indicator below).
Gain Ratio: This screwdriver adjustable control determines how
much the ANC22 will increase program volume, relative to a given
increase in ambient noise. A minimum setting ('1:2') produces a
1dB increase in program volume for every 2dB increase in
'average' ambient noise level. This is good for applications (such
as background music) where the program signals must remain
subdued. A maximum setting ('2:1') produces a 2dB increase in
program volume for every 1dB increase in 'average' ambient noise
level. This is good for applications (such as foreground audio)
where program signals must remain intelligible.
settings are also affected by 'sense' microphone placement. A
setting of '1:1' is a good starting point for most applications. Once
Gain Ratio has been set, press the Setup Button. The Gain Ratio
Indicator will go off, the control settings will be stored in non-
volatile memory, and the ANC22 will enter the normal operating
mode. NOTE: Once setup is completed, the Setup Button may be
disabled. Max Level, Sample Time, & Gain Ratio controls may be
enabled to allow adjustments during normal operation. These
adjustments will not be stored in non-volatile memory without
repeating the setup procedure (see Options on pg. 6).
Bypass Switch & Indicator: When pressed in, this switch will
defeat any ANC22 program gain increases, and set the program
volume to minimum (as determined by the Min Level control). The
adjacent indicator will light whenever Bypass is enabled. NOTE:
During normal operation, this indicator functions as a Rate
Indicator for each sampling period (if Bypass is not enabled).
3
ADVANTAGE ANC22
Ambient Noise Compensator
setup
bypass
o
on
rate
Gain Ratio
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