Test Your Knowledge of Audio Equalizers
True or false: An audio equalizer is so-named because it's intended to ?equalize? the output relative to the input of a circuit. If you think you know, take our test.
1. TRUE. In technical terms, the function of any equalizer used to improve the sound quality of an audio system is to create the inverse transfer function of the signal preceding it. So if certain frequencies are deficient or too loud, the purpose of the equalizer to is restore the balance by boosting and cutting frequencies.
2. FALSE. While Bell Labs was probably the first user of equalization circuits, they were fixed, passive devices, which were part of the telephone equipment — not a standalone outboard device. John Volkman of RCA is credited as being the first person to use a variable equalizer, and he used it for cinema sound reproduction systems.
3. TRUE. Along with Art Davis and Jim Noble, the trio developed the first 1/3-octave passive filter set, known as the “Acousta-Voice” system, for Altec Lansing in 1967.
4. TRUE. A passive equalization filter can't really boost — it can only attenuate adjacent frequencies, thereby creating a relative increase at the “boosted” frequency band.
SOURCE: RANE CORP.