Biamp ANC22 User Manual

ANC22

Ambient Noise

Compensator

Operation Manual

®

Biamp Systems, 10074 S.W. Arctic Drive, Beaverton, Oregon 97005 U.S.A. [phone] http://www.biamp.com

an affiliate of Rauland-Borg Corp.

blank

print update

Nov 2/98

Ambient Noise Compensator is a stereo controller,

gain to compensate for changes in

TABLE OF CONTENTS

Rear Panel / Connections
Front Panel / Setup
Applications
Options
Specifications / Block Diagram
Warranty

pg. 2
pg. 3

pgs. 4 & 5

pg. 6
pg. 7

ANC22

INTRODUCTION

The ADVANTAGE
which automatically adjusts system
background noise levels. An internal microprocessor senses ambient noise via
a microphone input, compares it to the program signal, and adjusts the
program level accordingly. The ANC22 is ideal for any system troubled by
fluctuating noise levels, such as restaurants, factories, and airports. Setup is
simple and straightforward, and the ANC22 is covered by an ADVANTAGE

Five Year ‘Gold Seal’ Warranty.
ANC22 features include:

♦ balanced stereo program input & output on plug-in barrier

♦ works with balanced or unbalanced, stereo or mono signals

♦ stereo program input selectable for +4dBu or -10dBu levels

♦ balanced/unbalanced noise-sensing input on plug-in barrier

®

ANC22

®

♦ noise-sensing input includes +24V phantom power switch

♦ noise-sensing input with 30dB pad accepts mic or line level

♦ noise-sensing via single mic or multiple mics (external mixer)

♦ adjustable minimum & maximum program level settings

♦ adjustable sample time & program-to-noise gain ratio

♦ automated setup including options to prevent tampering

♦ bypass switch defeats gain adjustments (sets to minimum)

♦ incorporates AES recommended grounding practices

♦

marked and UL / C-UL listed power source

♦ covered by Five-Year “Gold Seal” Warranty

1

REAR PANEL / CONNECTIONS

BIAMP SYSTEMS

Portland, Oregon

an affiliate of

27V

~

50/60 Hz
10 watts
class 2 wiring

Rauland-Borg Corp.

MADE IN U.S.A.

Output: These plug-in barrier strip terminals are for connection to
the input of a sound system equalizer/amplifier. The Output
provides a balanced stereo line-level program signal, with
automatic level adjustment to compensate for changes in ambient
noise. The ANC22 works equally well with a mono program signal
connected to either the left or right Input/Output. For connection to
unbalanced equalizer/amplifier inputs, wire high to (+) and ground

ý

to (

), leaving (-) unconnected. The Output has an additional 6dB

of gain when used in a balanced fashion.
Input: These plug-in barrier strip terminals are for connection to

the output of a program signal source. The Input accepts a
balanced stereo line-level program signal. The ANC22 works
equally well with a mono program signal connected to either the
left or right Input/Output. For connection to unbalanced program
signal sources, wire high to (+) and ground to both (-) & (
Input will accept either +4dBu or -10dBu nominal level signals (see
Input Level Switch below).

Input Level Switch: This push-button switch determines the
proper gain at the Input, allowing the ANC22 to accomodate
various program source signals. When depressed, the Input Level
Switch selects -10dBu as the appropriate Input signal level (+10dB
gain). This is good for program sources (such as CD, tape, etc.)
which are typically unbalanced line-level signals. When released,
the Input Level Switch selects +4dBu as the appropriate Input
signal level (-4dB gain). This is good for program sources (such
as mixers, equalizers, etc.) which are typically balanced line-level
signals.

R

output

L

This device complies with Part 15 of the FCC Rules.
Operation is subject to the following two conditions:
(1) This device may not cause harmful interference, and
(2) This device must accept any interference received,
including interference that may cause undesired operation.

ý

). The

input

L

R

input
level

+ 4

-10

sense input

-30dB
pad

out

in

phantom

power

off
on

Sense Input: These plug-in barrier strip terminals are for
connection of an external microphone, which is used to pick up
room ambient (background) noise. An internal microprocessor
then samples the noise, calculates an ‘average’ noise level, and
adjusts the program signal level accordingly. The microphone
should be of the balanced, low-impedance type. Condenser
microphones are recommended (see Phantom Power Switch
below), although dynamic microphones are acceptable. For
applications where ambient noise is evenly distributed throughout
the room, sensing microphones with ‘omnidirectional’ or
‘hemispherical’ pick-up patterns are prefered. For applications
where ambient noise is more localized, ‘unidirectional' pick-up
patterns may be more appropriate. If multiple microphones are
desired (to cover a larger area) an external microphone mixer may
be used (see Pad Switch below). Microphones should be placed
within a room so as to pick up both ambient noise and a moderate
amount of program signal from the sound system.

-30dB Pad Switch: When depressed, this push-button switch
provides 30dB of attenuation, to compensate for different signal
levels at the Sense Input. Depress the Pad Switch when Sense
Input signal levels exceed the normal operating range of the front
panel Sense Level control, or when line-level input from a
microphone mixer is desired.

Phantom Power Switch: When depressed, this push-button
switch provides +24 Volts DC phantom power to the Sense Input,
for powering a condenser type microphone. CAUTION: The

Phantom Power Switch must be released (phantom power off)
when the Sense Input is to be connected to a line-level source,
such as a microphone mixer. Always turn levels down before
switching phantom power.

2

FRONT PANEL / SETUP

sense level

+ ++ +

low peak

min

level

max
level

10 sec

1 sec 5 min

sample

Power Switch & On Indicator: This switch turns power on, and is
also used to enter setup (see Setup Button & Indicator below).

Setup Button & Indicator: This momentary push-button &
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
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

1:1

30 sec

2.5 min

2:1

1:2

gain

time

ratio

while the Min

ADVANTAGE ANC22

rate

Ambient Noise Compensator

bypasssetup

on

o

sense min max time ratio overload

setup

6391812 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. Gain Ratio
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 non­volatile 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