System Configuration ~ Inputs and Outputs | 33 |
The Speech Leveler is a compander that is optimized for speech audio. It quickly equalizes the difference in speech levels in the room without bringing up noise. If you use AGC with the Speech Leveler, set the AGC Response Time to >2 seconds.
AGC adjusts softer and louder input audio to a consistent level that you select (the target level). The target level range is from
Set the Target Level first, then apply the amount of maximum gain that you want the AGC to apply to the signal. Maximum gain range is 0 to 18dB in 1dB steps. The default value is 18dB. AGC occurs after the gain and filter settings in the audio signal path.
The Active Gain meter reflects the overall gain at any given moment. Click the white box next to the meter to enable it.
The Response Time adjustment determines the total AGC engage/disengage response time. The Threshold determines the decibel level at which you want the AGC to engage. Setting the threshold toward the higher end of the scale (near 0) reduces background noise to a greater degree. The Response Time is measured in milliseconds. Target Level and Threshold are both RMS.
Figure 3.27. AGC/Speech Leveler window
All meters in | ||
✍ peak | meters. | The target |
level | and | threshold |
controls in the AGC/SL window reflect RMS values.
P Pwr (Phantom Power)
Phantom Power toggles the phantom power on and off. Phantom power is an auxiliary power source to power certain types of microphones. The XAP 400’s phantom power voltage is 24VDC. Default is On.
AEC
AEC opens the Acoustic Echo Canceller window. To enable the acoustic echo canceller, click Enabled, then select the reference. Any one of the eight outputs, four expansion bus references, four virtual references, or Speaker output can be selected.
PA Adapt and AEC Reference
If you select an expansion bus reference, the Define PA Adapt/AEC Expansion Bus Ref window opens so you can identify which expansion bus output you want to use as the AEC’s reference. You can also open this window from the toolbar.
Figure 3.28. Define PA/AEC |
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window and toolbar button | Figure 3.29. AEC window |
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