Weak current College】 【specification for audio operations - address small and medium-sized microphone issue whistling dance hall.

<br> Outdoor concert and dance halls and the use of professional audio, the majority of imported equipment, it should be said that the high reliability. The main problem is the operator's professional-quality, genuine with eligible tuner unit is very small. This .article is targeted at small and medium-sized dance hall audio equipment operating points, can be used as a reference for practice. In addition, in small and medium-sized dance halls as microphone acoustic feedback caused by the phenomenon of self-excited Whistler, .is common to use a headache, because frequent Whistler will make guests' disappointing, sound effects whatsoever, in severe cases, can cause damage to the equipment. Therefore, the phenomenon of self-excited screech is singing the sound use of an important issue, .described below. <br> First, the sound equipment on, shutdown sequence <br> <br> Should the order by the former to back up, ie the audio source device (CD, LD, DVD players, recorders, recorders), audio .processing equipment (compressors, Exciter, effects, divider, equalizer, etc) to the audio power amplifiers to the TV, projector, monitor. Shuts down in reverse order, you should close the power amplifier. This action prevents open, shutting down the impact .of the device to prevent burning power amplifier and speakers. <br> <br> II. preparation before singing - debug <br> <br> 1. the power amplifier's volume control potentiometers are transferred to the Max position; on the accompaniment of .music and sound mixer handset tap faders should be placed on the 0dB; mixer tap GAIN input gain are placed in a location is fine; the total volume of the mixing console Fader start at minimum position (lower); mixer sound compensation knob is placed in .the middle position. <br> <br> 2. test accompaniment channel, that is, use the CD disk or LD coiled songs music, the sound mixer anxious-jump man enjoyed Clay's son, near the border to-6dB, songs and accompanying .music is typical of the volume; but it is necessary to pay attention to the volume you want to spend pleasant, moderately large easy sound that fatigue and unbearable.-Should the Hall Yinyuan different position to listen to the result. If stereo quality sound and .video, music, etc. The tracks should be your own familiar songs, adjust volume can be repeated (adjustment tap GAIN gain) and tap tone compensation until the sound is satisfied. At the request of the music should be aggressive, beauty, treble not .shrill, bass cannot clear cloudy, requirements, such as the female voice of tooth sound clearly audible, but not too heavy. Tap faders at 0dB, total volume faders at 0dB, regulating tap GAIN input gain knob makes around 0dB AU table indicates, the .system achieves rated output power. But the normal working hours, the total volume faders - like tune in - or - 10dB following 6dB, less than the rated output power. <br> <br> 3. test the microphone channel. In General, .at least to prepare two microphone channel. Try the receiver sensitivity and dynamic properties, and then add reverb and accompaniment music singing, singing after the reverberation processing, should be better than the original song sound more mellow, full and there are levels, rich presence .. Microphone volume adjustment: tap faders at 0dB, microphone volume adjustment tap GAIN input gain knob to tap peak led occasionally flashing, total output power measurement by AU table indicates. <br> <br> 4. for small Orchestra Auditions for tuning, that .is, to a variety of musical instrument microphone for carrying audio and signal an audition, according to the proportion for reproducing music style. <br> <br> 5. adjust the video image, that is, the projector and TV should adjust its brightness ., contrast, color saturation knobs make it clear and colorful images. Sound should be comfortable working with DVD player and karaoke, familiar with the disc on the song list. Note in a formal concert, you should press the DVD player on the D / A .key. Inclined original singing sound. <br> <br> 3. adjustment of the audio processing equipment <br> <br> 1. room equalizer. Room equalizer has two functions: one is to adjust the sound quality, cover the Hall reverb .time cause an imbalance of frequency response; the other a important role in the Suppression of a band, suppression of squealing sound feedback. Room Equalizer should maintain normal sound engineering debugging add decided. <br> <br> 2. press the filter. In .audio engineering to press for an important device, its role: to compression or restrictions on the programming of dynamic range, prevent overload or distortion, amplifier and the speakers have a protective effect; another important role is to improve the program loudness (this can be .done by hearing clearly have felt). <br> <br> Data compression is adjusted as follows: <br> <br> (1) noise gate GATE: led light noise gate closed sound. Up to squelch function. When the input signal .landing to the threshold level begins to shut down, the noise gate General placed between 0PEN-20dB. <br> <br> (2) the compression threshold level THRESHOLD: decided to start compression level, usually placed-10 to 0dB, start compression .gain reduced GAINREDUOTION (dB) led starts off. <br> <br> Compression ratio RATT0: over 2: 1; <br> <br> Action time: 10ms ATTACK placed; <br> <br> Release time: keep O. .3s RELEASE. <br> <br> 3. reverberator. The current widely used digital reverberator. This class of machine internal curing many different reverb effects to choose from. Adjusting the yinyuan deal with a variety of reverb reverb effect audition, record individually sing .there can use, when the tuning may at any time using the keyboard in use. <br> <br> 4. tuning elements (to manipulate sound mixer) <br> <br> 1. arrival transfer work to control indoor yinyuan, tuning .should be sniffing za and listen to headphones, listen to the main channel and to listen to the channel. Adjusting the sound should be familiar with listening yinyuan and on-site sound, sound quality adjustment relies heavily on personal hearing. <br> <br .> 2. use a compressor, and actuators to increase loudness of the sound and beauty. Actuator adjustments mainly by hearing, you should press the device instruction manual will sound tuned to round the ear. <br> <br> 3. the song with .reverb and beautification. On non-professional singer aggravated due to mask the noise, reverberation and audible defect. <br> <br> 4. volume hours that enhance the low frequency and high frequency; the volume increase frequency when appropriate, to enhance the .sound of luminance. <br> <br> 5. tuning to singing. When the songs appear before gradually lowering down the accompaniment, to highlight a song. 3-frequency attenuation should - 5dB, high-frequency attenuation 7kHz above should 3dB, near .the lift in the low-frequency 200Hz may intensify, 2-3-6dB 4kHz upgrade can be clearly felt the song bright. Disco or rock music you should pay attention to significantly enhance the low frequency (40 - 100Hz) and high-frequency ( .7-20KHz). <br> <br> 6. enhance bass is not cool rotation compensation button to avoid the power output is too large to damage the amplifier and the speakers. On the low-frequency adjusting the equalizer also true requirements. < .br> <br> 7. If there is a sound feedback whistling cry, should promptly that the yintai total volume faders to remove squealing voice drop down, find out why and then gradually pushed. <br> <br> 8. failure of the .main channel is not broadcasting, you can pass back to listen to the speaker of the rotation angle of the temporary substitute for the main channel, the continuation of the singing. For singing with a microphone, should have a backup, when the receiver is available .backup instead of silence. Laserdisc player should be backed up when a VCD faulty backup alternative when available. <br> <br> 5. acoustic feedback (whistling cry) inhibition of <br> <br> 1. microphone acoustic feedback whistling of self .-excited call is established and Kara 0K Hall of common phenomenon, due to the presence of acoustic feedback, General PA systems gain can be very large. Sound feedback whistling happened because: <br> <br> (1) microphone is too close to .loudspeakers, microphone is to point to the speaker; <br> <br> (2) a mixer on reverberation excessive regulation; <br> <br> (3) microphone volume adjustment is too large; <br> <br> (4 .) powered compressor; <br> <br> (5) acoustic design defects within the Office. <br> <br> 2. for the above reasons can take the following measures: <br> <br> (1) the activities for .the singer's stage a scope limited, in this context should not occur having a voice. In other words, the singer should not be too close to the main speaker, Lord speaker response in the wings; the singer of the station should not make the receiver .forward links to speaker. <br> <br> (2) of the stars of stage and acoustic treatment should be conducted, should be installed on both sides of the wall and sound-absorbing materials. <br> <br> (3) .plug in the compression, the compression ratio should be set to <= 2: 1, action time to 10ms, release time 0.3s. <br> <br> (4) of the regulation on the reverb sound mixer and volume don ' .t drive too large. <br> <br> (5) these measures are ineffective, you can adjust the equalizer, easy to produce screech of frequency attenuation. How to do the following: <br> <br> The equalizer the frequency point .location to record; then, the model act. Increase the volume (total with mixer faders adjust), the system just produce self-excited, Equalizer on the spin button to start from the low-frequency rates, one by one to the effective elimination .of self-excited screech of frequency, based on experience in General only one self-excited oscillation frequency (eg 250Hz), near the frequency to drop down 3-5dB, remaining frequency should keep the original records. <br> <br>.