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Bi-amping andtri-amping is the practice of using two or threeaudio amplifiers respectively to amplify different audio frequency ranges, with the amplified signals being routed to different speaker drivers, such as woofers, subwoofers and tweeters. With bi-amping and tri-amping, anaudio crossover is used to divide a sound signal into different frequency ranges, each of which is then separately amplified and routed to separatespeaker drivers. Inpowered speakers using bi-amping, multiple speaker drivers are in the samespeaker enclosure. In some bi-amp set-ups, the drivers are in separate speaker enclosures, such as with home stereos that contain two speakers and a separatesubwoofer.
Bi-amping is the use of two channels of amplification to power each loudspeaker within an audio system.Tri-amping is the practice of connecting three channels of amplification to aloudspeaker unit: one to power the bass driver (woofer), one to power the mid-range and the third to power the treble driver (tweeter). The terms derive from the prefixbi- meaning 'two',tri- meaning 'three', andamp the abbreviation foramplifier.
It differs from the conventional arrangement in which each channel of amplification powers a single speaker. Bi-amping typically consists of a crossover network and two or more drivers. With ordinary loudspeakers, a single amplifier can power the woofer, mid-range and tweeter through anaudio crossover, which filters the signal into high- medium- and low-frequencies (or high- and low-frequencies in 2-way speakers) – a mechanism that protects each driver from signals outside its frequency range. However, the passive crossover itself is inefficient, so splitting the frequencies electronically before these are amplified is a way to avoid this problem. In such a case, each amplifier powers a frequency range determined by anactive crossover to each of the drive units. The technique is primarily used in large-scale audio applications such as sound amplification for concerts, in portablepowered speakers and byhi-fi enthusiasts.
A speaker system has to be wired to accommodate either configuration, typically with two sets of binding posts, one set for the bass and one set for the mid-highs. A single amplifier can usually power a woofer and a tweeter only through a post-amplifiercrossover filter, which protects each driver from signals outside its frequency range.
Bi-amping of speakers requires double the channels of amplification and can be accomplished using two ordinary amplifiers in either a vertical or horizontal arrangement.
Most audible differences are subtle. If at all noticeable, many benefits of bi-amping cannot be realized if passive crossover networks of a speaker system are not removed.[1] Benefits include transients are less likely to cause amplifier overload (clipping) or speaker damage, and reduced intermodulation distortion, elimination of errors introduced by low-frequency passive crossover, reduction of load presented to the power amplifier, better matching of power amplifier and speaker driver and others.[2] In large professional sound systems, Bi-amping is pretty much the norm with the greater benefits easily outweighing the costs. All speakers are two-way transducers and can introduce current back into the driving circuit from ambient sound. The driving amplifier tries to control the effect of this with its damping factor (having a high resistance to such current), but with a passive crossover, this current can still leak across to the other driver units in the circuit. A Bi-amped system is therefore able to better resist ambient sound feeding back into the circuit. With high volumes and larger venues, such ambient feedback can have a significant damaging effect to the overall sound.