Operating skills and debugging methods of professional audio equipment

Release time:

2021-10-29

Summary： From front to back, start the machine from sound source equipment (CD player, LD player, DVD player, VCR, VCR) → audio processing equipment (voltage limiter, exciter, effector, divider, equalizer, etc.), audio power amplifier, TV, projector and monitor. When stopping, the order is reversed, and the power amplifier should be turned off first. This operation prevents the switch from affecting the device and burning the amplifier and speakers.

1. the on/off sequence of audio devices

From front to back, start the machine from sound source equipment (CD player, LD player, DVD player, VCR, VCR) → audio processing equipment (voltage limiter, exciter, effector, divider, equalizer, etc.), audio power amplifier, TV, projector and monitor. When stopping, the order is reversed, and the power amplifier should be turned off first. This operation prevents the switch from affecting the device and burning the amplifier and speakers.

Preparation before 2. performance-debugging

1. Adjust the volume control potentiometer of the power amplifier to the large position; The accompaniment music and microphone shunt thrusters on the mixer shall be set to 0dB; The gain of each shunt gain input on the mixer shall be set to the adjustment position; The total volume thruster of the mixer shall be set to the small position (lower end); The sound quality compensation knob of the mixer is set to the middle position.

2. Test the accompaniment channel, that is, use CD or LD discs to play songs and music, and slowly push the total volume of the mixer to near-6dB. At this time, the volume of the song and accompanying music is roughly normal; however, it should be noted that the volume should be moderate and pleasant. Too loud sounds can easily make people tired.

The tuner listens to stereo audio and video, music quality, and more at different locations in the lobby. The playing track should be familiar with itself, and the volume (shunt gain) and shunt sound quality compensation can be adjusted repeatedly until the sound effect is satisfactory. The demand for music effect should be strong and beautiful. The treble should not be harsh and the bass should not be cloudy. The song should be clear. For example, the sound of a woman's teeth should be clear and audible, but not too heavy. Set the shunt thruster to 0dB and the total volume thruster to 0dB. Adjust the shunt gain input button to make the VU meter indicate about 0dB. At this point, the system reaches the rated output power. However, during normal operation, the total volume booster is typically adjusted below -6dB or -10dB, which is below the rated output power.

3. Test the microphone channel. In general, at least two microphone channels should be prepared. First try the sensitivity and dynamic performance of the microphone, then add reverb and accompaniment music to sing. After reverberation, the tone of the song should be more mellow, full, layered and full of scene than the original. The adjustment of the microphone volume; the shunt thruster is set to 0dB, the microphone volume is adjusted, the shunt gain input button is adjusted, and the shunt peak level indicator flashes occasionally. The measured value of the total output power is indicated by the Vu meter.

4. Test and adjust the small band, that is, test the microphone pickup and electrical signals of various instruments, and balance the sound ratio according to the music style.

5. Video image adjustment, that is, projectors and color TVs should adjust the brightness, contrast, color saturation and other knobs to make their images clear and colorful. As a radio association tuner, he should be proficient in the use of DVD players and song players and familiar with the location of the disc on the song purchase order. Please note that during the formal singing, the D/a key on the DVD player should be pressed to eliminate the original singing.

Adjustments to 3. audio processing equipment

1. Room equalizer. The room equalizer has two functions: one is to adjust the sound quality to make up for the unbalanced frequency response caused by the reverberation time of the hall; another important function is to reduce a certain frequency band and reduce the howling caused by acoustic feedback. The room shall be balanced to the position set during sound engineering commissioning.

2. Pressure limiter. In audio engineering, voltage limiter is also an important device. Its functions are: First, compress or limit the dynamic range of the program, prevent overload or distortion, and protect the amplifier and speakers; another important function is to increase the loudness of the program (which can be clearly felt through hearing). The adjustment data of the voltage limiter are as follows:

(1) Noise gate: When the indicator light is on, the noise gate is closed and has a silencing effect. When the input signal drops to the threshold level, it starts to close, and the noise gate is usually between open and -20dB.

(2) Compression Threshold Level Threshold: Determines the level at which compression begins. It is typically set to -10 to 0dB. When compression starts, the gain decreases, and the gain (DB) indicator starts to light up. (3) Compression ratio: set to 2:1(4) Action time attack: set to 10ms(5) Release time release: set to 0.3s.

3. Reverberator. At present, digital reverberator has been widely used. Many different reverberation effects are solidified in such machines. The tuner should try to sing and listen to the various reverb effects of the reverb used one by one, record the available programs, and call up with the keyboard at any time during the tuning process.

4. tuning points (main operation console)

1. The ballroom tuner works in the control room. When tuning, the main channel and the return channel should be monitored using the monitoring speaker and the monitoring headset. The tuner should be familiar with the relationship between the monitoring sound and the live sound, and the adjustment of the sound quality depends to a large extent on the individual hearing.

2. Use voltage limiters and exciters to increase the loudness and beauty of the sound. The adjustment of exciter mainly depends on hearing, and the sound is full and pleasant according to the equipment operation manual.

3. Beautify songs with echoes. For non-professional singers, reverberation should be appropriately increased to cover up noise and vocal defects.

4. When the volume is small, pay attention to increasing the low frequency and high frequency; when the volume is large, appropriately increase the intermediate frequency to enhance the brightness of the sound.

5. Tuning is dominated by singing. When the song appears, the accompaniment is gradually lowered to highlight the song.

For the sound quality compensation of popular songs, in principle, the low frequency attenuation around 100Hz is 3 ~ 5dB, the high frequency attenuation above 7kHz is 3dB, the improvement near 200Hz can be strengthened, and the improvement of 2~4kHz is 3 ~ 6dB, which can obviously feel the bright singing. For disco or rock music, we should pay attention to greatly increasing the low frequency (40~100Hz) and high frequency (7~20kHz).

6. When improving the bass, do not turn the compensation button forcefully to avoid damage to the amplifier and speakers due to excessive output power. The low frequency adjustment of the equalizer also requires the same method.

7. In case of acoustic feedback whistle, the total volume propeller of the mixer should be pulled down quickly to eliminate the whistle, and then push up gradually after finding out the reason.

8. When the main channel fails to play, the rotation angle of the return speaker can temporarily replace the main channel to continue singing. The microphone used for singing should be backed up. When the microphone is muted, a standby microphone can be used instead. The DVD player should also have a backup. When the DVD player fails, it can be replaced with a backup device.

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