Fig. 5
3. Now bend the headband wire to fit your
head. Put the foam-block wire behind your
ear. Then you can bend the earpieces to fit
snugly around your ears. The back of the
headband should fit firmly against the back
of your neck.
4. Next, adjust the foam pad snug against
your head or neck. To do this, bend the wire
that goes into the foam block. CAUTION! Do
not bend the boom itself — just the foam-
block wire. A snug fit of the foam pad pre-
vents boom bounce when you move around.
5. Be sure that the thumbscrew is still loos-
ened a little. Move the boom in or out, and
left or right, to center the mic directly in
front of your lips. The foam pop filter
should press firmly against the lips. This
is necessary because the mic cancels
sounds that are not close to it. Also, it keeps
the boom from bouncing. Tighten the
thumbscrew and you’re done.
Once you’ve adjusted the headset, it should
remain in that position - no further adjust-
ments are needed. You can still swing the
mic up or down, away from your lips, if you
don’t want to be heard on the P.A. — or use
the mic on/off switch programmed for
“press off” operation.
After several hours of use, the foam pop
filter can become clogged with moisture,
giving a muffled sound. Periodically wash it
in mild detergent and water. The foam pop
filter is held in place by a removable ring.
Additional WS-6 pop filters can be ordered
from AKG’s Parts Department.
How to insert a battery in the CM311 A
belt pack
1. Access the battery by sliding open the
battery cover.
2. Insert a fresh 9V alkaline battery (Mallory
Duracell MN9100 or equivalent) into the
battery tray. The battery cover shows the
correct polarity.
3. Replace the battery cover. To prolong
battery life, turn off the battery switch when
not in use.
If you’re using phantom power, and the
battery switch is on, the battery will take
over automatically if phantom power fails.
After 85 hours of use, or if the sound is
distorted, it’s time to replace the battery.
How to program the mic on/off switch
The mic on/off switch can be programmed to
work in three ways:
* Push-on/push-off.
* Momentary on.
* Momentary off (as supplied).
To change the switch operation, open the belt-
pack case by removing the three screws. Set
the switch as shown below:
The LED lights when the mic is on.
Architects’ and Engineers’ Specifications
The microphone shall be the AKG/Crown
Model CM311 A or equivalent. The
microphone shall be a head-worn, noise-
cancelling,
cardioi
The
axis
The
headband
thumbscre
Mode
pack
permanentl
shielde
phon
includ
necto
Mode
batte
phanto
batte
on/off
Nomina
or 1.2
148
shall
response
a uniform
dow
model
Mic
AKG/C
gua
malfunction
thre
See
info
Ser
If th
erly
connecte
you
defective, return the complete product in its
original packaging to one of the addresses
below
support call
+43 676 83200 888.
cardioid type of electret-condenser design.
e microphone shall exhibit excellent off-
s response and gain-before-feedback.
e microphone shall have an adjustable
headband, adjustable boom with locking
thumbscrew, and foam pop filter.
Model CM311 A shall include a battery belt
pack. In the CM311 A, a 42-inch,
permanently
attached,
two-conductor
shielded cable shall connect the micro-
phone to the belt pack. The belt pack shall
include a 3-pin pro audio (XLR type) con-
nector.
Model CM311 A shall be powered by a 9 V
battery in the belt pack, or by 18 to 48 V
phantom power. The belt pack shall have a
battery on/off switch, a programmable mic
on/off switch, and a “Mic On” LED.
Nominal open-circuit sensitivity shall be 4
1.25 mV/Pa. Maximum SPL shall be
148 dB SPL for 3% THD. Equivalent noise
shall be 27 dBA nominal. Frequency
response shall be 50 Hz to 17,000 Hz with
uniform off-axis response, over 20 dB
down at the rear null. The AKG/Crown
model CM311 A is specified.
Microphone Warranty
AKG/Crown professional microphones are
guaranteed
unconditionally
against
malfunction from any cause for a period of
three years from date of original purchase.
e enclosed warranty sheet for additional
information.
rvice
the microphone does not function prop-
y, check that it is aimed correctly and is
connected as described in this data sheet.
If
you determine that the microphone product is
defective, return the complete product in its
original packaging to one of the addresses
below. For further assistance or technical
support call the international helpdesk at
+43 676 83200 888.