Waves API - 550A & 550B Plugin
API - 550A - EQ provides reciprocal and repeatable equalization at 15 points in 5 steps of boost, divided into three overlapping ranges. Its high and low frequency ranges are individually selectable as either peaking or shelving, and a band-pass filter can be inserted independently of all other settings.
API - 550B - Four overlapped EQ bands, is invaluable as both a problem solver and a sweetening device. With 7 switchable filter frequencies spanning up to 5 octaves per band, the 550B’s “Proportional Q” automatically widens the filter bandwidth at minimal settings and narrows it at higher settings.