Anti-Feedback System; Manually Ringing Out A System; Using The Feedback Wizard; Pre-Feedback Wizard Checklist - QSC TouchMix-30 Pro User Manual

To View or Change Sample Rate:
Your DAW software will also likely require some configuration to connect with the TouchMix-30 Pro. See your DAW software documentation for
information on this topic. There is also a guide to configuration of some common DAW software at www.qsc.com.
NOTE!: User buttons may be assigned to Arm / Disarm and select Track or Input as the source for all channels at once. "User
Buttons" on page 24

Anti-Feedback System

The TouchMix-30 Pro includes twelve narrow-band, anti-feedback filters on each output (eight filters for TouchMix-8 and TouchMix-16). These
filters are extremely useful for eliminating feedback frequencies while having very little effect on overall tonal balance. The filters may be adjusted
manually or automatically using the "Feedback Wizard" (see below).

Manually Ringing Out a System

In order to identify feedback frequencies, it's necessary to deliberately make the system feedback. This process is known is "ringing out" or
"squeaking" the system. Here's how an experienced sound system operator would go about it.
• Bring all mixer output faders to minimum
• Place all microphones and speakers in position
• Bring the input level of power amplifiers or powered speakers to the level that will be used in performance.
• Bring the input gain and channel faders for the mix you're working on to the approximate level they will be at during the performance.
• Warn anybody who is around that you are going to make some unpleasant noises.
• Slowly and carefully bring up the fader for the output you are working on until the system begins to feedback.
• Be prepared to quickly back down the fader if the feedback really starts "taking off".
• It may be necessary to have someone talk or shout into a microphone to "excite" the system into feedback.
• Adjust the frequency of a filter to match the feedback frequency and reduce the gain until the feedback goes away.
• Repeat until you have achieved sufficient system gain without feedback.
Using the Feedback
The tricky part is to identify the feedback frequencies. Fortunately, you don't need to identify them because your TouchMix has built-in tools to do
that for you. Here's how to use those tools.
To access the Anti-Feedback System:
Aux Masters

Pre-Feedback Wizard Checklist:

• Microphones and loudspeakers in their performance positions.
• Input channel gain and level settings approximately at performance levels.
• Zero the filter bands or touch Reset. The Wizard won't use a filter unless its gain is set to 0.0 dB Cut.
• Output you're working with set at a level that's slightly below its threshold of feedback.
• If the space is very quiet, turn on some noise using the control in the Feedback Wizard.
• The Wizard will cause feedback to occur briefly at levels that may be uncomfortable to those who are sensitive to such things. Let them
know it's coming.
Follow the step-by-step instructions on the screen. The Feedback Wizard gradually brings up the Master Fader. As it does, feedback ring
1001108-01-C
Mixer Setup
Menu
izard
Anti-
Aux 1
Feedback
Sample Rate 44.1 kHz
Feedback Wizard OR
17
48 kHz
Anit-
Feedback