Telos TWOx12 - Page 154

TELOS TWOX12 USER’S MANUAL
DETAILED CONFIGURATION & REFERENCE
CHAPTER 7 142
The problem here is that the mic processing combines with the TWOx12’s
internal AGC to increase gain in the feedback path. Depending on the mic
processor used, the feedback margin can be reduced by many dB. The
TWOx12’s internal AGC has a internal adaptive smart-gate function to
prevent inappropriate gain increase, however it is thwarted by this additional
processing.
If it is not possible to get an unprocessed mic signal, try to set the mic
processor in such a way that room noise is not “sucked-up” during pauses.
You can also try reducing slightly the output the mic processor (or set the
Input Gain selection in the Audio menu to the next higher setting, thereby
reducing levels into the unit). The level to the caller should be ok since the
Send AGC will compensate, however you will force that AGC towards its
maximum gain and thereby reduce how much gain it can add to the feedback
path.
• Try repositioning the mics or speakers. It also helps, of course, to use
directional mics. Customers have reported good results with cardioid mics
such the EV RE-20 and the Shure SM-7.
• Add equalization to the monitor path. Acoustic (and electrical) resonances
usually result in pronounced peaks in the feedback response. Since there are
likely to be only a few pronounced peaks in this response characteristic,
flattening out those peaks with an equalizer can significantly improve the
feedback margin. A spectrum analyzer connected to the output of your mic
processor will help detect the frequency of those peaks.
• If necessary, soften acoustic room reflections by adding curtains or wall
treatments.
The discussion above is intended to help in those situations where open speakers are
a requirement. Whenever possible, of course, it is best to use headphones to listen to
the caller audio. We have found the best scheme is to have the phone monitor speaker
mute when the mic is turned on. If your mix minus has provided a means for the mic
signal to be active even when the mic channel is turned off, the system can be used
like a speaker phone when the taking calls off air. When the call is on the air the
speaker mutes, however the talent will generally be wearing headphones when on
mic in any case.