571
7
Front & Rear Panel Overview
Chapter 4
PAGE MIC Trimpot
- Screwdriver adjust level control provides up to 26dB attenuation of signals
from the page mic preamp. This control does not affect the House Page input. This control is
always active, regardless of the 571s operating mode.
SENSE MIC 1 Trimpot
- Screwdriver adjust level control provides up to 40dB attenuation of
signals from the sense mic 1 preamp. This control is always active, regardless of the 571s operat-
ing mode. Do not adjust this control after calibration.
SENSE MIC 2
trimpot - Screwdriver adjust level control provides up to 40dB attenuation of signals
from the sense mic 2 preamp. This control is always active, regardless of the 571s operating mode.
Do not adjust this control after calibration.
AVERAGING TIME Control
- Sets the time period, in seconds or minutes, used by the 571 for
averaging sound pressure level changes: from 1.2 seconds to 5 minutes. Also affects the time
required to change the SPL to its newly computed value.
PAGE OVER MUSIC control
- Determines attenuation applied to music signals during paging
announcements: from 0dB to -14dB.
RATIO
∆
SENSE:
∆
OUTPUT Control
- Sets the ambient/gain ratio: from 2:1 to 1:2. This deter-
mines whether the 571 makes a smaller gain change than the ambient level(2:1) or a larger gain
change than the ambient level(1:2).
OUTPUT GAIN TRIM control
- Provides manual adjustment of overall output gain over a 20 dB
range, at any time. This control may be remotely located, which disables the front panel output
gain control.
GAIN (dB) display
- LED bargraph that indicates amount of gain being added to the sound system
by the 571. In calibrate mode, the display serves as an error-condition indicator and as a prompting
device.
LEVEL SET MIN
control - Active only during calibration; sets the minimum operating level of the
sound system: from 0 to -20dB.
LEVEL SET MAX
control - Active only during calibration; sets the maximum operating level of the
sound system: from 0 to +20dB.
MODE
switch - Switches the 571s operating mode sequentially between Operate mode, Cal mode
and Bypass mode, in that order.
Cal mode is indicated by the flashing Set Min or Set Max indicators in the bargraph display.
Bypass mode is indicated by the flashing bypass LED in the bargraph display.
Operate mode is indicated by the absence of flashing indicators; in this mode, the bargraph display
shows gain change.
POWER LED
- Indicates presence of AC power.
CALIBRATE
SENSE INPUT
ERROR
INPUT ERROR
SPL COMPUTER
571
POWER
10
15
MAX
20
0
MODE
-10
-5
0
-15
-20
30 40
20
15
9
26
GAIN (dB)
MIN
LEVEL SET (dB)
5
+5
5
2
+10
T
U
P
-5
T
U
O
:
E
S
N
E
RATIO (dB)
1:1
-10
1:2
2:1
0
GAIN TRIM (dBr)
OUTPUT
BYPASS
S
7
MUSIC (dB)
PAGE OVER
14
0
TIME
3
2
1.5
AVERAGING
4
5
MIN
1.2
60
30
SEC
SENSE
SENSE
1
2
PAGE
MIC
PAGE/MUSIC
