Setup For Feedback Control - Shure DFR11EQ User Manual

Setup for Feedback Control

The DFR11EQ will operate stand-alone as a feedback reducer. However, when connected to a
personal computer running the supplied DFR11EQ software, additional options are available. See
Computer Interface for details.
There are two basic ways in which to set-up the DFR11EQ: The "Ring Out" method and the
"Insurance Policy" method. Each is valid for different situations. The "Ring Out" method is a
preemptive measure in which the system gain is raised beyond the normal setting to deliberately
make the system feed back. The DFR11EQ will then set its filters, and the system gain is then
reduced slightly, and the system is stable and useable. This set-up method is primarily used for
systems which are operated near the feedback point and need an extra margin of stability.
For the "Insurance Policy" method, the DFR11EQ is simply installed in the sound system, but
filters are not set prior to use. The DFR11EQ adds extra insurance against feedback: the system is
not expected to feed back, but if it does, the DFR11EQ is there to catch it. This set-up method is used
for systems which already have sufficient gain-before-feedback, but need protection from the
occasional stray feedback which can occur due to non-stationary microphones or user-adjustable
gain controls.
Setup
1. Connect the DFR11EQ in the desired signal path location. See Audio Connections.
2. Set the input and output level DIP switches to the appropriate settings for the sensitivities
of the connected equipment.
WARNING: Other equipment may potentially be damaged after DFR11EQ
power off if the DFR11EQ input is set to +4 and the output is set to –10. It is
recommended that you avoid using this setting.
3. Set the system gain to minimum, and power up all of the equipment.
4. Slowly raise the gain of the system, and set the gain of each microphone to achieve the
desired level.
5. The red CLIP LED should illuminate only on the highest signal peaks. If it illuminates
more frequently, check to see that the input level switch is set properly. If it is, lower the
level of the signal going into the DFR11EQ.
6. At this point it is highly recommended to equalize the sound system with the DFR11EQ's
built–in equalizer (see Computer Interface ) or an external equalizer. The DFR11EQ's
feedback reducer is more effective on a well–equalized sound system.
Ringing Out the System ("Ring Out" method only)
1. If necessary, clear any notch filters in the DFR11EQ by pressing the CLEAR button. Turn
off the BYPASS and LOCK LEDs if they are not already off.
2. Slowly raise the gain of the signal going through the DFR11EQ. When feedback occurs,
the DFR11EQ will insert a filter deep enough to stop the feedback.
3. Repeat step 2 until all fixed filters are set. (There are 5 fixed filters, unless changed by
the user via the computer interface.)
4. Lower the gain by 3 to 6 dB to stabilize the sound system.
8
Main Menu