Shure DFR22 - Press to Lock;Hold to Clear; Bypass DFR Filters; Changing Presets; Front Panel Lockout

Shure Incorporated
6/16
Holding the clear button down while Auto Clear is engaged will only clear the dynamic filters.
Press to Lock/Hold to Clear
Pressing these buttons locks the filters at their current values. If Auto Clear is not engaged, holding them down for
three seconds resets all filters. If Auto Clear is engaged, holding them down only resets dynamic filters. When the
PRESS TO LOCK/HOLD TO CLEAR LEDs are illuminated, the Lock function is engaged and no filters can be
added or changed. Also, the Auto Clear timer is suspended.
Bypass DFR Filters
Pressing the DFR BYPASS button suspends the feedback reducer operation and bypasses existing feedback fil
ters. It does NOT affect any other processors. When the DFR BYPASS LED illuminates, the feedback reducer is
disengaged.
Changing Presets
The Preset Indicator on the front panel displays the number of the active preset. You can scroll through all presets
stored in the device by pressing the arrow keys on the preset selector. When you select a preset number, the dis
play blinks. If you press the LOAD button within five seconds, the device will make the selected preset the new
Live preset. If you do not press the LOAD button, the preset will not change and the display will return to the origi
nal Live preset.
The preset indicator and controls are also used for setting the number of hours after which each dynamic filter is
removed when engaging Auto Clear.
Front Panel Lockout
When this DIP switch is in the "Unlock" position, all front panel controls are enabled. When it is in the "Lock" posi
tion, all front panel controls are disabled. However, all front panel indicators still function and show the state of
each parameter.
You can override this DIP switch using the DFR22 software and individually enable or disable each button on the
front panel of the DFR22. Access to the DFR22 via a computer can only be disable by setting the appropriate se
curity level through the DFR22 software.
DFR22 Theory
Feedback Reduction
No sound system (microphones + mixing/signal processing + power amplifiers/loudspeakers + room acoustics)
has an absolutely flat frequency response. When the level of a sound system is increased, the frequencies at
which peaks occur will be the first to exceed the feedback threshold. The DFR22 attenuates these frequencies,
flattening the response of the sound system. The system can then operate at a higher overall level.