Behringer MicroHD HD400 Ultra-Compact 2 Channel Hum Destroyer

Short version: product does exactly what it's supposed to do. Hum in my home theater subwoofers is gone. For $25 (or if it had cost $225) I couldn't be happier! Two-minute install and only additional cost was a couple 12" RCA patch cables and some RCA-to-TR adapters. No brainer!I run a 9.2 (7.2.2) home theater and started to notice the dreaded ~60Hz hum in Sub1 and less so in Sub2. As an old-school audio guy I was a) perplexed because b) this setup never had the issues and c) I already had everything on the same ground, hospital-grade outlet, line-interactive UPS, and multiple PS Audio Noise Harvesters. My stereo is on the adjacent circuit, so I keep this area of the house buttoned up power-wise. Nonetheless, the sound presented, and I needed to solve the issue.I assumed it was the nothing-special plate amp (rhymes with Blayton Baudio) I used when building Sub1, and I retrofitted it to passive w/SpeakON conx and changed amplification to a Behringer NX3000. At any reasonable gain the sound persisted.Went through the whole routine of changing all the power distribution, sub cables, unplugging everything from the receiver to troubleshoot, checking my line/power/speaker-level proximities, etc., to eliminate possibilities. Hum persisted.Put this chap inline between the miniDSP 2x4HD out and the to-sub cables; hum is effectively GONE. You can still hear a *little* if the NX4000 gain is turned all the way up, but no amp should ever be turned that high anyway and it's barely audible at a gain level logarithmically higher than I'll ever use. And this is WITHOUT converting to balanced - runs are still unbalanced and effectively noise-free.In sum: Immediately did the trick at a budget price. Thank you, Behringer!

I have a Schiit Modi -> RCA -> Schiit Magni (USB powered) -> RCA to 1/4" cable -> Alesis RA-100 powering two KEF Q150s. I have dealt with ground loop feedback and noise for YEARS with other speaker setups plugged into my computer and had finally had enough. Nothing worked - changing power cables, what devices were plugged into what outlets, different USB interfaces, etc. The problem was exacerbated by any GPU-related task, and playing games on speakers led to some extremely loud and annoying noise. Even idling on the desktop, there was always some amount of gross digital sounds. After plugging in this device with two more quarter inch cables, I am FREE from my ground loop woes!! There is now absolutely zero audible noise coming from my speakers under any computer load. This wonderfully simple device worked for me and I hope it can work for you as well!

EDIT: Literally overnight i have a different problem; this time CAUSED by the behringer HD400. God does not want me to live a hum-less existence and I have made my peace with my purgatorio.I had the same problem that somebody else had in these reviews: Scratchy noise coming through my studio monitors that would get way worse when the gpu was under load and moving the mouse. This was something that had driven me so crazy before trying to diagnose that I had swapped out gpus, ALMOST my motherboard, and sold my HS7's altogether. But after discovering this product and seeing someone with my EXACT problem find relief with this, I decided to order it. I was so shocked and almost in disbelief to find that the sound goes away COMPLETELY when I swap this bad boy into my signal chain in between my interface and monitors. Now everyone knows Behringer is not synonymous with quality in most things i.e. pedals, midi controllers, etc... but whatever sorcery they have going on in this little black box is just incredible. This is going with me wherever I and my studio go because I know I'll be okay anywhere and not have to worry about interference. Thank you so much for this amazing black box.

The media could not be loaded. I had been battling getting PC “noise” coming through my speakers (KRK Rokit 6) for awhile, especially in programs using high cpu or graphics (games with high framerate). This just took care of that, plugged it in and it solved it.There is still the sound from the powered speaker (low consistent hiss), that wasn’t related to the PC, but that is very manageable and what I was expecting anyway.In the video, I’m idle in a game with high frame rates (over 150) and you can hear the noise. This noise also would change/be amplified when moving the mouse or scrolling. Then I routed the speaker through the HD400 and the noise is gone. I haven’t spent a lot of time with it yet but I didn’t notice any discernible difference in audio quality or volume with my setup.The price point and simplicity of this product made it a must try for me, and the fact it worked all the better. Highly recommend if you’re experiencing issues like I was.

I have three of these, and they do the trick. I have a lot of synths and mixers that have ground loop and hum issues, and I didn’t want to buy multiple pricey DI’s for every input.Does it “tone suck”? Not noticeably. Is it the cleanest, best-sounding DI in the world? Also no. But is it good enough for most applications? Definitely. It seems to slightly reduce high-end sheen as well as overall amplitude (which is typical) but it’s nothing that isn’t workable.The outside enclosure is solid. The inside is basically just a small transformer glued to the side. Don’t think it would hold up well on the road.Regardless, great small solution for the studio.