This is an expander / dual channel denoiser
rack unit standard model
The general configuration is relatively simple, like a compressor, the principle is very simple, after it takes a bit of experience and dexterity in handling comes. Change a setting can affect the other, so you have a little experience (ie a great day max!).
I'm pretty impressed with the capacity and responsiveness of the machine: I use to reduce noise caused by abusive rack tendon ducts in series, reducing the noise of old synths, old tables, etc.. before a compressor to prevent it is too breath and increase the signal / noise, and I must say that it does so with flexibility and musicality (compared for example to "denoiser" VIRTUALIZER the behringer is the day and night, one because of the size and slaughter indiscriminately in the sound of emanière mathematics, the other acts flexibility and adapts to the signal).
This is not a magical effect: if the acton is transparent in most cases, it may happen that removes some slightly sharp (on ride cymbals and reverb tails for example), but never on vocals, bass, and it is noticeable with careful listening with headphones, and if the breath is very present
I use it for almost a year, I was using previously plugins catering to "clean" my catch, but I prefer to work in hardware and acquisistion before, and I think this can compete with the aisémenet noisefilter Waves. Its big advantage is that it is musical, clean enough, and can regain dynamqiue fairly natural, it feels during the mixdown.
TPAS're my role model but brand Rocktron Hush (Hush is because the manufacturer of the chip réduciton of breath, and developed under his own name such racks before the technology and model are redeemed by Rocktron), but the model is exactly the same.