The howling sound created by feedback from a guitar, amplifier or microphone is familiar to most people who have attended a rock concert or used any sort of amplification equipment. Some musicians use controlled feedback for aesthetic reasons, but controlling feedback can be vital to creating a pleasant experience. One way to control feedback in any situation requiring electrical amplification is to use a feedback eliminator. A feedback eliminator helps automatically control volume and frequencies to prevent feedback.
Feedback occurs when amplified sound loops back through the speakers and is reamplified, creating an unpleasant screeching sound. Feedback can occur because of a number of factors. Among these factors are the placement of the microphones and the interaction among various amplifiers in the sound setup. Equalizers are often used to control the loops that can result in feedback. Reducing the amplifier volume when feedback occurs also will stop the loop, and usually some experimentation is necessary to produce the best possible configuration of equipment, instruments and microphones in any given room.
A feedback eliminator helps automatically control volume to prevent a feedback loop from occurring. Certain frequencies are more likely to cause feedback than others, so the feedback eliminator monitors frequencies and automatically reduces volume if the sound approaches one of these frequencies. Sound systems can make use of a variety of feedback eliminators depending on the needs of the individual system. All of these elements help detect feedback frequencies and help produce a cleaner, more pleasant sound.
Different instruments produce feedback loops in different ways, as do microphones and amplifiers. For example, the vibrations of an acoustic guitar can produce a hum that must be controlled differently than the feedback sounds produced by an electric guitar pickup. Microphones present different challenges, as well, requiring the sound technician to be sure that the microphones are not set up facing the speakers and that they are placed in such a way as to capture the sound most efficiently. A feedback eliminator intended specifically for use with a guitar or with a microphone will help optimize the sound.
In addition to using a high-quality feedback eliminator, other elements can help produce an optimal sound. In order to reduce the possibility of feedback, a sound technician will adjust elements of the sound system so that they are less likely to interact with each other. The way a system is organized depends not only on the equipment but on the shape, size and overall acoustical qualities of the room or venue. Experienced sound technicians can balance all of these elements to ensure excellent sound quality.