Output Trim - Extron electronics SSP 7.1 User Manual

Output Trim

The Output Trim sliders control the audio signal level for each individual channel output. Only
channels that are enabled in the current speaker configuration are available; the others are
displayed but cannot be adjusted. Output trim is adjustable from
value for each output channel is shown in the text box.
Figure 43. Output Trim
NOTE: The maximum output volume is tied to the output trim. When an output trim value
is higher than dB, the highest possible output volume is reduced by that amount. For
0
example, if the highest output trim for any channel is set to
volume is dB.
‑5
Extron recommends using a Sound Pressure Level (SPL) meter to set the output trim for each
speaker:
Set up the SPL meter at the sweet spot in the room.
1.
2. Send a test signal, generated as described in
speaker in turn. Extron recommends using the Dolby Noise signal and sending the signals to
the speakers manually.
NOTE:
The test signal should have a sound level at least 20 - 30 dB above ambient
levels.
3. Measure and write down the sound pressure for each speaker.
4. To avoid decreasing the maximum output volume (see the note above), Extron recommends
that you use the speaker with the lowest SPL reading as the zero reference point. Then
attenuate all the other speakers by the required amount to balance all speakers.
In the example below, the SPL readings for five channels are given in second column.
Channel 4 has the lowest reading and is used as the zero reference point. The difference
between each speaker and the zero reference is calculated in column 3. This is the
adjustment that must be made to the output trim for that channel.
Channel SPL Reading
1 75
2 76
3 79
4 74
5 77
Table 4.
Output Trim Adjustment
‑24
+5
Test signals
on page 32, to each individual
Output Trim Adjustment (dB)
-1
-2
-5
0
(zero reference channel)
-3
SSP 7.1 • Setup and Control Software
dB to dB. The current
+12
dB, the maximum output
35