User’s Guide – 900MHz Stereo Audio Transmitter & Receiver
7
Setting the Transmitter’s Audio Modulation Level
With an active audio source connected to the transmitter’s
AUDIO
INPUTS
,
adjust the
AUDIO LEVEL
control on the front panel such
that the green
MODULATION LEVEL
OK
indicator is illuminated
whenever audio is present, and the red
PEAK
indicator flashes only
on the loudest audio transients. To prevent distorted audio at the
receiver, the red
PEAK
indicator should not be illuminated
continuously.
IMPORTANT!
Properly setting the transmitter’s modulation
level is CRITICAL to satisfactory operation of
the transmitter and receiver. If the level is set
too low, the receiver will likely be plagued with
objectionable background noise (hiss). If the
level is set too high, distorted audio and/or
interference on adjacent channels is likely to
result.
Note:
The audio source device may have a volume control that
adjusts the level of the audio signal(s) being fed to the transmitter’s
inputs. If your source device (e.g. MP3 player, portable CD player,
or PC sound card) is so equipped, initially set that device’s volume
control to its approximate midpoint. Then, adjust the transmitter’s
AUDIO LEVEL
control as described above. Use the following
guidelines to “fine tune” the settings:
If the audio output at the receiver suffers from excessive
background noise, the source device’s volume level is
probably set too low. Increase the source device’s volume
control a bit, and readjust the transmitter’s
AUDIO LEVEL
control accordingly.
If the audio output at the receiver is distorted, and/or if the
transmitted audio program can be heard on (or interferes
with) either or both of the channels adjacent to the selected
channel of operation, the source device’s volume level is
probably set too high. Reduce the source device’s volume
control a bit, and readjust the transmitter’s
AUDIO LEVEL
control accordingly.
8
Applied Wireless, Inc.
Adjusting Headphone Volume (Receiver)
If desired, stereo headphones or earbuds equipped with a standard
3.5mm mini-phone plug may be used with the AR900-32 receiver.
Insert the plug into the
HEADPHONE
jack on the rear panel. The
output level at this jack may be adjusted using the
VOLUME
control
on the front panel.
Note:
The receiver’s
VOLUME
control only affects the volume at
the headphone jack. It does not affect the volume at the receiver’s
line level audio output phono jacks.
EQualization (Receiver)
When headphones or earbuds are used with the receiver, the
EQ
button on the receiver’s front panel may be used to select one of
four preset audio equalization (tone) profiles, enabling you to
select the audio response characteristics that you prefer. The
chosen equalization profile only affects the audio from the
headphone jack on the rear panel. The audio signals at the line
level audio output phono jacks remain “flat” regardless of the
equalization profile chosen for the headphones.
Momentarily pressing the
EQ
button will cause the 2-digit
CHANNEL
indicator to display the current equalization profile. The
four equalization profiles are as follows:
E1:
No Equalization (flat response)
E2:
Bass Boost
E3:
Treble Boost
E4:
Bass Boost + Treble Boost
Pressing the
EQ
button again (while the display is indicating the
equalization profile) will advance to the next profile. The 2-digit
CHANNEL
indicator will automatically revert to displaying the
receiver’s current channel when the
EQ
button has not been pressed
for two to three seconds.
