ABSTRACT
The frequency spectrum of instruments could be altered by means of simple equalizers. Since the invention of the parametric equalizing (EQ) in 1967, it is possible to apply corrections surgically. Hi-pass and lo-pass filters are integrated with many equalizers. Masking happens when our ear is unable to distinguish two similar signals playing at the same time. For example, a 3-kHz tone will mask a softer 2.5-kHz tone but will have little effect on the audibility of a soft tone at 1200 Hz. Narrow bandwidths and larger amounts of gain will cause more side effects. Passive EQ is the oldest type of EQ. Although not completely free from phase issues, passive EQ exhibits fewer smearing effects than conventional EQ. Linear-phase EQ is more transparent than conventional EQ, it will preserve a better musical balance and can colorlessly treat the harmonic spectrum of an instrument or mix.
