vissonic VIS-FS100-A, Руководство пользователя, Страница: 19 / 20

VISSONIC Electronics Ltd.
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4. Feedback suppressor calibration
4.1 Calibration
Increase the master volume to the required level before commissioning to test feedback. In
contrast to traditional feedback reduction systems, feedback suppressors suppress feedback before it
occurs. Therefore, disabling the suppression algorithm may result in immediate feedback.
After checking that there is no problem with the connection settings (or before the event or
meeting), debug the feedback suppressor and give the feedback suppressor an input source signal to
measure the acoustic environment and set the adaptive filter.
When there is a signal source:
Input the signal source to the connected channel (for example, in a meeting scene, use normal
volume and a slightly higher volume to speak). When the device detects that the input signal is too
high, the input signal overload indicator (3) lights up. In this case, please use the signal level switch
on the back of the device to adjust the input signal level until the input signal will not be overloaded
under normal use volume.
When a howling sound is heard, the feedback suppressor will work at its feedback suppression
limit. In this case, please lower the overall signal gain (for example, by lowering the microphone gain
on the mixing panel or by lowering the main volume on the power amplifier).
When there is no signal source:
Press the calibration button (8), it will generate -6 dBr random noise and keep for a few seconds,
so that the feedback suppression algorithm can be quickly calibrated. During this time, the calibration
indicator (9) will light up.
4.2 General advice to prevent feedback
1. Make sure to arrange the microphone and speakers correctly. Please pay special attention to
the directivity of the microphone and the speaker and the appropriate distance between the
microphone and the speaker. This is especially suitable for buildings with long reverberation times,
such as halls, large conference rooms, etc.
2. The microphone and speaker must be used in accordance with the manufacturer's technical
guidelines.
3. Improve poor room acoustics, such as covering highly reflective (flat) walls and floors with
curtains or carpets.
4. Do not use speakers that exceed its rated power. Due to the power compression of the speaker,
the feedback margin is reduced. Try to make sure there is enough headroom.