I purchased this unit several years ago to use with a MOTU 828 and did not connect it or use it until recently. I did not expect it to be very effective, but that was a big mistake. This thing is really excellent for the price and is an outstanding tool to use with vocals or instruments. It can reduce the high volume notes in a vocal to much more even volume and also has de-esser, limiter, expander, and gate functions. I am astonished at the quality and like the way this works much more than online compressor functions I've used. I recommend this to anyone who is looking for an actual effective compressor. This is the real deal and is a fraction of the price usually seen for this type of unit.