Shelves is another strange little Airwindows EQ. This one’s a simple two-band shelf… that’s all Airwindows-ized in subtle ways.
The crossover’s altered in the way that Highpass and Lowpass are. As near as I can work out, what’s happening is that if you boost Treble, it gets harder. If you cut it, it gets softer. If you boost Bass, it seems to get softer. If you cut it, it gets harder. Seems to work…
Also, it’s using Density techniques rather than straight gain altering, so if you boost something it gets subtly more saturated and comes forward, and if you cut it it drops back. The whole thing is coded neatly and cleanly, so it works alongside recenter plugins without sounding inadequate. Its only weakness is really just that it’s a two-band shelving EQ without fancy tricks, best used for very subtle tone shaping.
Its strength is that it’s quite awesome at this very simple tone shaping, if you know all that its doing under the surface. If you just need to tilt things a bit or doctor the overall balance of things, without doing anything obvious, Shelves is awesome.