Equalization is indeed the process of altering the level of distinct frequency bands within about an audio stream in sound recording as well as reproduction. An equaliser is indeed the circuit or piece of equipment that does this.
To alter the bass and treble on most hi-fi equipment, simple filtering are used. The frequency content of such an audio source may be tailored considerably more easily with graphic and parametric equalisers. Broadcast as well as recording studios utilise sophisticated equalisers that can make even more comprehensive changes, including removing undesirable sounds or enhancing the prominence of certain instruments or voices. Equalizers are “frequency-specific volume knobs” because they “change the loudness of audio signals at certain frequencies.”
Equalizers are being used to correct or regulate the response of microphones, instrument pick-ups, loudspeakers, as well as hall acoustics in recording studios, radio studios, and production control rooms, as well as live sound reinforcement and instrument amplifiers, including such guitar amplifiers.
Equalization can also be used to eliminate or minimise undesired noises, highlight certain instruments or voices, improve specific components of an instrument’s tone, or battle feedback in a public address system. Equalizers are also used in music production to modify the timbre of individual instruments and vocals by changing their frequency content, as well as to fit individual components within the mix’s broader frequency spectrum.
Prior to the introduction of electrical amplification, the notion of equalisation was initially used to rectify the frequency response of telephone lines utilizing passive networks. Originally, equalisation was used to “compensate for” (i.e., correct) an electric system’s uneven frequency response by adding a filter with the opposite response, restoring the transmission’s fidelity. The net frequency response of the system might be a flat line since its response at any frequency is identical to it’s own response at every other frequency. As a result, the term “equalisation” was coined.