I've been using this in my home multi-source/multi-room audio system (lots of ground loops there!) for a year now. It removes the typical ground loop hum exactly as it is supposed to. Being a cheaper unit, I was initially afraid it might ruin my sound quality. However, everything sounds just fine. Just to verify things, I brought the unit to work to test it out. Using a function generator and oscilloscope, I compared the In versus Out voltage from 20 Hz to 25 kHz. Above 50 Hz, it is pretty much flat for all practical purposes (+/- 0.5 dB in a straight-ish line). Below 50 Hz, it drops off a bit, but still not too bad until you hit 30 Hz (-0.95 dB) and 20 Hz (-1.51 dB). All in all, this is much better than I expected for a nice cheap unit such as this. I have graphic equalizers on every zone, so I don't really care about the bass drop off, I can easily adjust for that. In short, buy this unit, it works great. If you need to, just turn up the low bass an extra click.