Eliminated hum in recording
592575
I bought this because I had a hum when recording to my Imac from a mixing board in a live enviroment. The hum was not audible during recording only on the recording itself.  I hooked this up and have had no hum in the recordings since.  Great device for what I needed.
201741
Well the product works, however there is a lot of feedback recorded by the microphone at all times.  With a decent audio program you should be able to remove it.
4055322
The Mic-Sense has high and low settings. It's very convenient to record without blank sound.
1367477
I downloaded this song to replace another MP3 download that has a discernible background hum at the beginning. Unfortunately, this is an exact copy of the file that I already have and it still has the hum.

I have the original vinyl album, so I guess I will need to digitize the song from the album so that I can eliminate the undesirable audio artifact. I also have Audio Cleaning Lab, so I should be able to clean it up. I guess all of the online music services are working off the same bad copy of the song.
595681
I am getting a ton of feedback on this device.  There is always a large hum.  This is typically when  something is not grounded properly but there really is nothing to ground.  I am perplexed.
945440
I purchased a new behringer audio interface, a new shure 48 microphone and this cable. When I plug the cable in there is a loud humming noise when I speak into my microphone. I'm not very experienced with audio equipment yet, but I know this isn't supposed to be happening. I saved money but I would rather save the headache and time of having to return this cable and ordering another.
4337777
you can fix it by turning the mic level lower and the mic sensitivity to 0 and the mic sounds fine now
1900191
I dealt with the noise of it by keeping it on all the time like white noise. After a while, I forgot about what that loud hum might be. I had smoke from wildfires this summer and it was a great machine to have.
3877514
The left audio RCA output on my Toshiba television developed a loud 60Hz ground hum. After determining that the issue was with the output and not a cable (though a better cable did partly reduce the hum), I noticed I also had an optical digital output on the back of my TV.

I purchased this $9.99 Portta box and a $4.99 Toslink cable. It took less than two minutes to connect the wires.

The hum is gone. Mission accomplished.

I did have to switch the TV audio output from Dolby to PCM. Be sure your television offers this option before buying this box. When watching streaming online video with a Roku connected to the HDMI input, the audio works with the TV's audio output set to Dolby (or PCM), but when watching a Bluray DVD, the PCM setting was required for the audio to work properly. There was a loud stuttering sound when it was set to Dolby.
4351495
Very loud static when recording, after hours of tuning/downloading special software and tuning with that it's still there but not as much.
4670124
Seems to do a reasonable job of capturing sound and is easy to use. But the loud hiss you hear in the quieter parts of your recording make it unusable for any serious music, which is what I wanted it for.
1068787
Great quality and very easy to use, my only problem is that I have yet to find a way to discard the sound you just recorded, for some reason you have to save first then delete, I wish there was a way to not save, so I would not have to browse the menu to delete the last recording.
177205
I reiterate what others have said (and I should have paid attention to)--there is a loud hum in the output.  If you want a good recording, don't buy this cassette player.
1595945
I have to agree with music fan from Texas.  The problem, though, is not too little noise reduction, but too much.  The high-pitched whistling he cites is, I think, an artifact of hiss reduction.  It ruins the whole set, in my opinion.  An awful shame, considering the importance of this music, and the fact that the remastering was otherwise most meticulously done.  BMG, why did you allow this to happen?
***LATER***The late John R. T. Davies, who was during his lifetime the world's foremost restorer of 78 r.p.m. recordings, confirmed in correspondence with me that the whistling noise I refer to is an artifact of the master recording and is not caused by electronic noise reduction. Specifically, it is caused by the cooling of the wax master during recording. There are ways of minimizing it during transfer and remastering, and I wish BMG had taken advantage of these.
521474
This is a small device designed to eliminate noise in audio systems when there is a grounding issue from shared power sources. I used this between a PC and a speaker and it did eliminate all noise (hum) and was simple to set up and use. It is a small, contained box with a separate cable that plugs in to either end. Mine had no manufacturing flaws and the connection to the included cable was secure. It had one function to perform, and it performed it well.

Note: I received a free sample of this product for my assessment.
4583733
Worked great. Eliminated humming and buzzing created by a PC connected to an audio mixer. Used three of these to isolate the six audio channels.
1419940
Short summary:
If your PC output is giving a hum to your nice speakers, I recommend this Behringer unit. If you are using the hum destroyer unit and find the hum is gone but now your audio quality is junk (like a bad tunnel), look into getting a dedicated sound card and using that with the Behringer hum destroyer. The sound card I bought was more in my price range but there are other models and other companies that sell dedicated sound cards as well.

Longer version:
I got some nice monitor speakers and after hooking them up to the line out on the back of my PC found an annoying hum was coming through. There was no hum from my FLAC player, no hum from the Mac, and it didn't seem connected to a specific outlet in our home. I bought the Behringer unit and that hum disappeared from the PC. Super happy.

A few weeks later my power supply died and took the pro-model motherboard with it and damaged the video card (which will need to get replaced later). We bought a decent consumer motherboard and new power supply, plugged everything in, and now the Behringer unit seemed to kill the audio quality as it sounds like I am traveling through a tunnel.
Not using the Behringer unit and plugged the line out on motherboard direct into my nice speakers had that same hum as before I bought the hum destroyer unit (no surprise).
Using PC speakers w/o Behringer was fine.

After doing some research I found the issue was not with Behringer, but with the audio output on the motherboard, specifically AC'97. I bought the dedicated sound card Sound Blaster Z from Creative and with the Behringer hum destroyer now everything sounds beautiful. Lesson learned - if the hum destroyer seems to hurt the audio quality, it isn't the hum destroyer's problem it is the sound output mounted on the motherboard. Get a good dedicated audio card and the problem should disappear.