Dynacord CMS 1000-3 Owner's Manual page 19

44 - FEEDBACK FILTER
The feedback filter is a very narrow banded notch filter, which is only active in a range that is extremely susceptible for
acoustical feedback. The FEEDB. FILTER rotary control sets the corresponding frequency range. Pressing the corre-
sponding button activates the filter. Several circumstances and conditions have an influence on how sensitive or insen-
sitive your system is for acoustical feedback. The following notes are meant to assist you in avoiding feedback and you
should take them into consideration even before you activate the feedback filter.
Best practice for avoiding feedback
1. Do not position the main speaker systems behind the microphones.
2. Switch off all microphones that are not in use.
3. Consider the microphones' different polar patterns and characteristics, when placing the monitor speakers.
4. Do not turn up the monitor system's volume higher than actually necessary.
5. Try to avoid extensive equalization on channels that you want to include in your monitor mix.
6. Keep in mind, that a microphone "behaves" different when somebody stands right in front of it.
7. Position the microphones as direct as possible to the sound source.
If you still have the feeling that the monitor system's acoustic output is not sufficient, after considering the above men-
tioned precautions, you can use the FEEDBACK filter to mute the frequency that tends to generate feedback the most.
Therefore, you have to perform the following steps:
Increase the MON 1/2 level until the limit is reached where feedback starts. The slightly "hovering" sound that you hear
is generated by the system itself. Switch on the feedback filter, turn the rotary control and set it at the mark where the
"sound" disappears. Switching the filter on and off lets you easily check whether you tuned in the correct frequency.
The feedback filter attenuates the level of the corresponding frequency band by about 9 dB. Since the filtered band is
extremely narrow, an alteration in the sound of your monitor system is hardly audible.
CAUTION: Please be extremely careful in driving the system just below the feedback limit. Careless operation,
resulting in feedback noise at high SPL, can cause severe damage to your speaker systems and – even
more important – the human ear.
45 - MUTE
The MUTE button mutes the MON 1/2 output signal. PFL signals are not affected.
46 - PFL
Through this button you can route the pre MON 1/2 fader signal to the headphones bus. The signal is outputted for lis-
tening via the headphones output. The setting of the MON 1/2 fader is not relevant for the signal's volume (Pre Fader
Listen). The meter instrument in the master section is simultaneously switched, so that the left LED-chain indicates the
level of the actually chosen channel (in dBu), leaving you with the opportunity for adjusting the level without routing it
to the MON 1/2 bus.
47 - MON 1/2
FADER
This fader controls the summed audio signal at the MON 1/2 output. When using the DIGITAL AUDIO INTERFACE as out-
put, and the Studio routing is selected (see page 27), this fader also controls the volume of sent channels USB 1 or
USB 2.
48 - USB 2.0
The USB interface of the CMS is a USB B (female) connector. Please refer to chapter "DIGITAL AUDIO INTERFACE" on
page 30 for more details.
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