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18
English --
SUGGESTED LOGIC APPLICATIONS
This section contains suggestions on the uses of the
AMS8100’s logic capabilities. Note that uses of these func-
tions are not limited to the listed applications. The user is limit-
ed only by individual imagination and creativity. For additional
suggestions and solutions to installation problems, contact
Shure’s Applications Group at 847--866--2525.
In the following paragraphs, the wiring diagrams refer to
the DB-25 connector pins shown in Figure 10.
Cough Button
The talker can turn off his or her microphone during
coughing or private conversations by installing an SPST push-
button switch between the MUTE IN and Logic Ground pins for
each channel to be modified (see illustration
COUGH BUT-
TONS
—Channels 1, 2 and 3 modified). When a channel is
muted, no audio is passed. (See “Dead Zone on MUTE IN De-
feat” in
Internal Modifications
section for more information on
MUTE IN logic.)
COUGH BUTTONS
M1
M3
M2
LOGIC
GROUND
Chairperson-Controlled Muting
The chairperson can, by activating a switch, silence all
other microphones and be heard without interruption. For op-
eration in this mode, connect all the MUTE IN pins together
ex-
cept that of the chairperson’s channel
, and wire an SPST
pushbutton or toggle switch between those MUTE IN pins and
Logic Ground pin (see illustration
CHAIRPERSON—CON-
TROLLED MUTING
—the chairperson is shown as Channel
1).
An alternative to a switch is to connect the chairperson’s
GATE OUT to the MUTE IN of other channels. When the chair-
person’s microphone activates, all other microphones mute.
NOTE:
If the chairperson’s microphone activates for
any
rea-
son (cough, sneeze, etc.) all other microphones will be muted.
CHAIRPERSON--CONTROLLED MUTING
CH. 1
M3
M5
M5
M7
M2
M4
M6
LOGIC
GROUND
Remote Channel-On Indicators
Remote indicators can be used to indicate when a talker’s
microphone is on. Connect the LEDs and a 5-volt supply to the
GATE OUT pins as shown in the illustration
REMOTE CHAN-
NEL-ON INDICATORS
(Channels 1, 2 and 3 shown modified).
To avoid switching clicks in the audio output,
do not
ground the
power supply negative terminal in the audio system or rack
ground.
IMPORTANT:
If a single cable is used for the micro-
phone audio signal
and
the LED dc power, separate shielded
pairs
must
be used. Failure to carry the dc power on a shielded
pair may result in audible clicking due to capacitive coupling
between the dc power lines and microphone lines.
5 V POWER
SUPPLY
+
--
R = 470
W
REMOTE CHANNEL--ON INDICATORS
G1
G3
G2
LOGIC
GROUND
, 1/4 W
R
R
Disabling the Gating Function (Bypass)
To keep certain microphones on at all times, wire the de-
sired microphone channel’s OVERRIDE IN pins together to
the Logic Ground pin. The selected channels now function as
they would in a non-automatic mixer (see illustration
GATING
BYPASS
—Channels 1, 2 and 3 modified).
GATING BYPASS
O2
O1
O3
LOGIC
GROUND
Inhibiting Gating for Unwanted Sounds
As described in the
Operating Principles
section, MaxBus
attempts to activate only one microphone per sound source.
Muting a microphone channel prevents its audio from appear-
ing at the mixer’s output. However, the muted microphone still
communicates with other mic channels via MaxBus.
A sound
source picked up by a muted microphone will not activate other
microphones.
Sound sources that may cause unwanted microphone
channel activation include:
·
A noisy fax machine or printer
·
A squeaky door
·
A paging system loudspeaker
·
An audio teleconferencing return signal loudspeaker