Vellum Pro

Vellum Pro sounds like a room rather than a device, and most of that comes from what happens in the first fifty milliseconds. Real early reflections arrive in front of the tail, so a voice sits inside a space instead of in front of a curtain of one — without them a reverb is silent for the whole predelay and then swells to its loudest a fifth of a second later, arriving after the source rather than with it. Low frequencies can be made to arrive fractionally later than high ones, and later again on every pass around the tank, which is what physical surfaces actually do and what separates a space from an effect. The decay itself was voiced against measurements of a reference hardware hall, band by band, and re-worked until the treble behaved the way a real tail does rather than the way a damping filter does.

The reason to reach for it, though, is that it gets out of the way. Every reverb with a ducking control turns the whole tail down when the source plays, which works and costs you the reverb. Vellum Pro measures many times a second which frequency bands the source is genuinely masking, and pulls the tail down only in those — so the space keeps its length, its width and its brightness and simply steps aside in the narrow places where it was competing. On a real vocal that holds meaningfully more clarity than ordinary ducking at the same tail level, and the gap widens the harder you push it. It also tells a consonant from a loud vowel, so sibilance and plosives get a faster recovery than sustained notes and words stay crisp without the whole performance pumping.