PS Engineering
PMA450C Audio Selector Panel and Intercom System
Installation and Operator’s Manual
200-450-0800
Page 3-6
July 2022
NOTE
It is also a good idea to keep the microphone out of a direct wind path. Moving your head through a vent air
stream may cause the
IntelliVox
® to open momentarily. This is normal.
The
IntelliVox
® is designed to work with normal aircraft cabin noise levels (70 dB and above). It loves air-
plane noise! Therefore, it may not recognize speech and clip syllables in a quiet cabin, such as in the
hangar, or without the engine running. This is normal.
If your cockpit is unusually loud or windy, PS Engineering recommends installation of a Microphone Muff
Kit from Oregon Aero (1-800-888-6910). This will not only optimize VOX performance, but will improve
the overall clarity of
all
your communications.
Manufacturer
Model
Mic Muff™ Part Number
Bose
Dynamic
Electret
M87 Dynamic
90010
90015
90020
David Clark
H10-30
H10-20, H10-40
H10-13.4
90010
90015
90015
Lightspeed
All
90015
Peltor
7003
7004
90010
90015
Pilot
11-20 & 11-90
90015
Sennheiser
90015
Telex
Airman 750, Echelon
AIR3000
90015
90010
Table 3-1 Mic Muff ™ Part Numbers
3.8.2
Intercom Volume Control (1)
The smaller inner volume control knob adjusts the loudness of the intercom for the pilot and copilot. It has
no effect on selected radio levels, music input levels or passengers' volume level. The green volume bar
indicator shows the level of the crew volume by default.
The outer, larger volume control knob controls intercom volume for the passengers. It has no effect on radio
or music levels. When the outer knob is moved, the green volume bar indicator will switch to show the level
of the passenger’s intercom volume, reverting to the crew after a few seconds.
Adjust the radios (at the radio itself) and intercom volume for a comfortable listening level. Most general
aviation headsets today have built-in volume controls; therefore, volume also can be further adjusted at the
individual headset.
3.8.2.1
Monaural headsets
The pilot and copilot positions work with stereo or mono headsets. However, IntelliAudio will not be pre-
sented correctly unless stereo headsets are used, and oriented correctly on the head, left and right.
NOTE: For the full effect of IntelliAudio® Dimensional Sound, stereo headsets must be used, and the
left/right orientation observed.
All
passenger
headsets are connected in parallel. Therefore, if a monaural headset is plugged in to a
PMA450C Stereo installation, one channel will be shorted. Although no damage to the unit will occur, all
passengers with stereo headsets will not hear one channel, unless they switch to the “MONO” mode on their
headset.
NOTE: Mono headsets that short the tip and ring (i.e. older models) will introduce some audio dis-
tortion when used. Modern, stereo headsets are recommended in all positions.
3.8.3
Intercom Modes (8)
The “
ICS
” pushbutton switch on the panel provides the selection of the three intercom modes
This button cycles through the intercom modes, from left to right, then right to left as: ISO, ALL CRW and
CRW, ALL, ISO. A green indicator shows which mode is currently active.
