【 Weak current College 】 Classic sound reinforcement technology: reduce sound reinforcement of acoustic feedback---Power By 【 China power house network 】

Sound reinforcement system is a set of audio engineering, tuning technology and architectural acoustics in one integrated system. There are many types of sound reinforcement systems, this expression is the microphone and speakers in the same field of sound reinforcement systems. Therefore, it's sound effects not only on system equipment, system design, System commissioning relevant, also with sound propagation environment. We all know, natural sound sources (vocal, musical instruments, sound, etc.) issued by the energy is very limited, transmission range is small, its volume increases as the distance increases spread gradually decay, and on-site sound reinforcement function is "heavily advertising", will stage the actors of the language, musical, singing through the microphone, the sound waves into electrical signals through the sound mixer and sound processor, power amplifier, and a series of professional equipment, electrical signals to enough energy to last from speakers reproduce true voice, to overwrite all need to hear the sound.
However, live sound reinforcement of sound loudness and not only by the system equipment, it is heavily influenced by the constraints of acoustic feedback. This is because the amplification system with microphone and speakers in the same field, the speaker output energy is part of the microphone picks up again. Continuous output, and constantly being picked up, and so forth, sent out of the sound quality will be bad, or even cause whistling, make amplification serious disruptions or even break. Since the acoustic feedback is objective, then, how to reduce acoustic feedback on the impact of the sound quality is audio workers at work require often thought. In fact, in many theatres, conference rooms, as the architect of the careful design, good sound architectural acoustical conditions on clear, uniform dispersion played a great role. Because of the work, the author often in some sound reflection grave, reverb time environment sound reinforcement, so get some work experience in this area. View the spot on the scene of the performance area, mass, building structures, and so on various aspects of the need for detailed understanding, if the venue is located indoors, you should consider building interior of the shape, size, layer high, wall surface decorating material, the performance area and audience area of distance, and so on; if the venue is located in the outdoors, you have to consider the audience area, population, climate conditions, outside interference noise, and other factors. In addition, the working area of the location is good, not sight will be affected by the interference of audience, etc. should also be included in the survey. If you feel that there is no suitable place, should keep the organizers put forward a revised views, such as work location can cause better, play areas and the distance between the masses area increases, and so on. Learn more about the program to the directors or sponsors for more information on program content, the performing arts, in order to decide how many and what type of microphone, the microphone is appropriate, performer's performances method determines the type of microphone. For example, the band generally use the cable to the microphone to sing and dance for expressing handheld wireless microphone or portable wireless microphone, and so on. Layout of the site according to the performance area, regional, environment characteristics determine the arrangement of the speakers. Speaker placement location and placement of sound reinforcement effect is greatly affected, consideration should be given to the microphone and speaker to have enough distance, and take advantage of the microphone and loudspeaker directivity increase microphone gain. At the same time it is necessary to pay attention to maintain the unity of the auditory and Visual, auditory (views) see all hear comes from the same direction. In some long reverberation time, acoustic reflex serious environment, it is best to use some of the radiation characteristics of good speakers, and take more decentralized way. Frequency response of the receiver's frequency response and not the wider the better, because the frequency response and wide, especially in the low frequency band will increase the likelihood of acoustic feedback, because either a microphone or speakers of low frequency directivity is very poor, low frequency feedback to agencies often are the primary factors. feedback Therefore, conditional microphone can be adjusted to lower its sensitivity, low frequency cut feature microphone for low frequency.
Reducing the use of microphone to minimize the work at the same time the number of the handset. For example, some performers only need to say a word or two, you can make him close to wearing a microphone actor. Tuner to eye wash hands often, and don't let those who do not use a microphone empty open and timely manner tuning faders down. Capture screech frequency in sufficient volume of the speakers, the handset away along the performance area-by-case basis, the capture by screech, on the frequency of the Group speakers equalizer to adjust individually. Through careful debugging system rehearsal rehearsal is a live performance is best and last chance for debugging system, through rehearsals can verify the reasonableness and stability of the system, you can master the various programmes of performances, sound dynamic, actors go station locations and paths. To remind the facilitator or the actors speak and microphone distance, do not deviate from or are too close together, the deviation will make sound vague, too close you will cause distortion. The best selection of wearable microphones directivity of the sound, and as close as possible to the clothes the neckline. The location of the speakers, microphone, volume xianfang compression, reverb, delay parameter for final adjustments, some actors may not attend rehearsals, to the Director or organizers understand these programme contents and form, at the same time in equipment and systems for the appropriate preparation. In rehearsal, the sound may appear blurred or sound reinforcement in Whistler, often causes are manifold: low frequency sound reinforcement has been removed, the volume is too large, the speaker of the radiation is and microphone pickup direction staggered. Rely on the performance of the regional group speaker recently power can reduce some of the actors go one path is the speaker, the system of device parameters are reasonable, and so on. To have enough sound pressure level allowance due to system debugging is less in the audience or empty field of subjective experience, sometimes seems to be enough volume, however once the formal performance, increasing number of visitors due to the sound-absorbing effect and crowd noise, sound volume tends to be much higher, in theory, music sound reinforcement to reach 80 ~ 85dB average sound pressure level, voice sound reinforcement for 70 ~ 75dB, taking into account the dynamic range of the audio signal, music sound reinforcement should have 10 ~ 18dB of margin, and sound reinforcementConsideration should be given to 6dB of allowance, so when you want to make the sound of breathing space. Down from high to low is secure, and from low to high increase is likely to affect the clarity of the sound or even cause whistling. Use of acoustic feedback suppressor weaken acoustic feedback effect in recent years, acoustic feedback suppressor was audio workers of all ages, it is the use of frequency-shift technology allows speaker microphone for audio and audio between the phase difference, thus undermining the conditions with phase overlays, for reduced sound feedback effects, improved audio gain and played a good role.