Ears-104
Commercial in Confidence
Copyright © 2021, all rights reserved by Exacom, Inc.
11
Chapter 5. System Testing and Adjustments
The f inal phase of the installation is testing and audio level adjustments. Most parameters associated with
the system integration will be correct at the f actory def ault values. However, certain parameters, such as
Vox Threshold and Vox StopDelay, will need to be conf igured f or each channel due to the individual
characteristics of each device being recorded.
VOX StopDelay is adjusted dif ferently f or radio recording and f or telephone recording due to the inherent
application. Telephone conversation are long two way and contain natural pauses. Radio transmissions
are usually short bursts of audio and one-way conversations. Theref ore, channels connected:
•
To radios are conf igured with the f actory def ault value of Vox StopDelay = 2secs
•
To telephone are conf igured with Vox StopDelay = 6secs
Each channel must be tested individually by f irst transmitting audio on each channel and monitoring the
associated Ears recorder. With the audio source active, the channel LED will light green and the capture
process will begin. If , however the capture process does not trigger then the line levels should be
examined to ensure the levels are satisf actory f or recording.
This can easily be done by selecting the Line Level screen on the OLED to monitor activity. With the
screen active, the line levels will be reported in decibel. Enable the audio source and examine the
reported change in level.
In the event the line level does not increase past -30db, gain can be applied to channel to boost the input
signal to an appropriate range. Ref er to appendix A f or instructions on adjusting the gain settings.
Alternatively, if the application requires that the audio is recording at the l evel it is presented, simply
adjust the Vox Threshold parameter such that it is greater than the line level without audio input and less
than the line level with audio input. Signals lower than -40db should be considered too low and need to be
handled external to the Ears unit.
Should Automatic Gain Control (AGC) be required, ref er to Appendix A f or details on conf iguration. AGC
can be enabled on a per channel basis. One of the common use cases of AGC is when one side of a
conversation is lower in volume than the other. AGC can be used to ensure a consistent level during a
conversation.
In some cases, a 4-wire audio interf ace is required. This is conf igurable per channel. Ref er to appendix A
f or details on how to enable 4-wire.
