How to solve the self-excited howling of microphone acoustic feedback.Wireless conference room audio

　　The audio equipment generally used in high-end KTV and large-scale outdoor performances are high-quality professional audio equipment, and the stability is relatively high. But why does the self-excited whistling still occur? Below, Jazz Dragon audio manufacturers explain the operating points of audio equipment in small and medium-sized dance halls, which can be used as a reference for formulating operating procedures.

　　One, preparation.

　　1. The volume control potentiometers of the power amplifiers are always adjusted to the maximum position; the accompaniment music and microphone split faders on the mixer should be set to 0dB; the gain of each branch GAIN input on the mixer is at the adjusted position; tuning The total volume fader of the console is placed at the minimum position (lower end) first; the sound quality compensation knob of the mixer is placed in the middle position.

　　2. Put in the CD and start the accompaniment music. At this time, the singing and accompaniment music have probably entered the normal working volume. Pay attention to the volume. Too big will make people tired and unbearable, and too small will make people feel that the quality of the audio equipment is low. The tuner should listen from every angle until every angle is satisfactory.

　　3. For the microphone test, the tuner of Zhunya will generally prepare two different microphones for reverberation processing. The sound should be more rounded, plump and layered than the original song, with a sense of presence.

　　Second, the sequence of audio equipment switches

　　It should be turned on in order from front to back, that is, the audio source equipment (CD player, LD player, DVD player, tape recorder, VCR), audio processing equipment (compressor, exciter, effect, frequency divider, equalizer, etc.) To audio power amplifiers to TVs, projectors, monitors. The sequence is reversed when shutting down, the power amplifier should be turned off first. This operation can prevent the impact of switching on and off the equipment, and prevent the power amplifier and speakers from being burned.

　　3. Adjustment of audio processing equipment

　　1. Room equalizer. The room equalizer has two functions. One is to adjust the sound quality and make up for the unbalanced frequency response caused by the reverberation time in the hall. The room equalizer should usually keep the position set during audio engineering debugging.

　　2. Tuning is based on singing. Before the vocals appear, gradually lower the accompaniment to accentuate the vocals. The low frequency should be attenuated by 3-5dB, the high frequency above 7kHz should be attenuated by 3dB, the mid-low frequency around 200Hz can be increased, and the 2-4kHz increase by 3-6dB can clearly feel the song's statement. For disco or rock music, you should pay attention to a large increase in low frequency (40-100Hz) and high frequency (7-20KHz).

　　4. Suppression of acoustic feedback (howling)

　　Acoustic feedback is a common phenomenon in general audio equipment, and it is also a difficult problem for many tuners to solve. The reasons for the reduction to prevent acoustic feedback are:

　　1 The microphone is too close to the speaker, and the microphone is pointing forward to the speaker;

　　2 The reverb adjustment on the mixer is too large;

　　3 Microphone volume adjustment is too large;

　　4 The compressor is not turned on;

　　5 Defects in the acoustic design of the hall.

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