ChannelEQ is an early four-band fixed-frequency EQ. It uses pretty normal EQ code—okay, I lied, it’s not really very normal at all.
The basic EQ code isn’t that unusual, but it’s two separate EQs interleaved (a common Airwindows trick). The bands are built up in such a way that if it’s zeroed out, it’s passing unaltered data. Then, the bands are doctored so that boosts are also offsetting that band a tiny bit ahead in time, in an attempt to make it stand out or recede back. Finally the bands are recombined, the output value produced by the interplay between the two interleaved EQs.
Because even in 2007, Airwindows code was downright weird!
ChannelEQ’s designed to work at 44.1K, like the early convolution-based plugins, and it is free. It runs three samples of latency.