Extron electronics SSP 200 User Manual page 54

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. Output
trim is adjustable from -24 dB to +0 dB. The current value for each output channel is shown
in the text box.
Extron recommends using a Sound Pressure Level (SPL) meter to set the output trim for
each speaker:
1. Set up the SPL meter at the sweet spot in the room.
2. Send a test signal, generated as described in
individual 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 to 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 following table, 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
1
2
3
4
5
5. Use any of these methods to adjust the output trim for each speaker.
• Grab and drag the slider bar to adjust output trim in 1 dB increments.
Click the up and down arrows besides the text box to adjust it in 1 dB increments.
•
• Click one of the output trim slider controls to activate it and use the <up arrow>
and <down arrow> keys on the keyboard to adjust it in 1 dB increments.
• Click one of the output trim slider controls to activate it and use the <Page Up> and
<Page Down> keys on the keyboard to adjust it in 5 dB increments.
Highlight the value in the text box, type a number (omit the dB), and press <Enter>
•
on the keyboard.
The Reset button returns the output trim values for all speakers to the default value (0 dB).
Test Signals
SPL Reading Output Trim Adjustment (dB)
75
76
79
74
(zero reference channel)
77
SSP 200 • Product Configuration Software
on page 22, to each
-1
-2
-5
0
-3
46