I helped a friend setup his new Epic 80-EP600 system this weekend. The receiver is a Denon AVR2807. The problem we have is the EP600 constantly buzzes or hums when there is no source material playing. It seems perfectly fine while watching a dvd. Stop the dvd and the humming begins. The humming even persists while listening to a cable music station.

I tried searching the forums since I figure I can't be the first one with this issue but couldn't find anything (probably searching using the wrong terms).

And before you all ask...

Volume half way or 9 o'clock.
crossover set to bypass.
phase set to 0.
trim set to flat.

Any ideas?

How close is the sub to either of the M80s? I seem to remember a review that said the M80 and EP600 could start "talking" to each other when nothing was playing and they were in close proximity. That's my only guess. Now let the real experts answer.

Have you tried taking out the ground screw?

Funny that the amateur would make a good guess. The M80 is less than 6 inches away. I thought of that but didn't try it since it was late. I'll try moving the sub tomorrow to see if that makes a difference.

Oh, it's probably not a good guess. I found the review I was thinking of, and it wasn't really humming or buzzing, but something much more severe.

http://www.6moons.com/audioreviews/axiom/axiom_2.html

"Making a long story short, I came to realize -- and had it verified by Axiom -- that if the subwoofer is placed too close to the speakers without a signal running through the system, the speakers and the subwoofer become... um, bored. They start talking to each other. I'm not sure who starts the conversation but the speaker talks to the sub, which responds in kind. As with any feedback loop, voices raise and eventually, it becomes an extremely loud conversation at an extremely low frequency. This electronic feedback conversation was notable in that it occurred at so low a frequency as to be inaudible. But it was reproduced with enough raw power to rattle the hell out of my room. It was at this point that I knew this thing was going to be fun! But I was going to have to send the speakers and sub to neutral corners."

Still, maybe it could have something to do with it?

Like Wid said, try removing the ground screw.

I moved the M80 around 4-5 feet away from the EP600 and it still hums. I removed the ground screw and the hum went down dramatically, but it still has a faint hum. Although it is much better, it won't go into standby mode. So, I still consider this problem unresolved.

One thing I did notice is if I turn the sub crossover to 40, it goes away completely. However this solution is useless since I want to keep the sub's crossover on bypass.

Still looking for ideas I guess.

I'm in the same boat. I removed the ground screw, and while the hum was considerably less, it's still there. I haven't tried a ground isolator yet. I'm upgrading to an amp/preamp combo this month, and I'm hoping that, as a side benefit, using an XLR connection to the sub will eliminate the hum. I'm not sure on your next course of action, but a ground isolator might be something to look at. Again, I defer to ANYONE else's opinion here.

http://www.axiomaudio.com/groundisolator.html

Since it goes away when the cross-over is set to 40, it's 60Hz hum from your house wiring.

If any of you can get rid of it let me know as I have the same issue on my 600. It's very low amplitude though so it only bothers me when I don't have anything playing and I'm purposely listening for it.

Maybe y'all should call Axiom...

The standard solutions are a filter for the sub cable and/or a filter for the AC receptacle. I've tried the filter for the AC receptacle and it didn't do anything. I haven't tried the filter for the sub cable because I don't know how exactly it works. If it's a 60Hz notch filter, no thanks as 60Hz and the band around it is contained in music after all.

Of course the other solution is running the sub cable in high magnetic permeability conduit but I'm not going there .

It seems to me that the most common cause of 60Hz hum is a ground loop caused by a cable or satellite connection. Have any of you tried unhooking the cable or satellite from your system to see if the hum disappears?

Should that prove to be the problem, often it can be solved by a Video Isolation Transformer such as those offered by Axiom or Parts Express. If you believe what they say on the web site, it does not affect video or audio performance.

I don't have cable or satellite connected up to any of my components. Not even the TV.

LOL! Well then a Video Isolation Transformer won't do you any good, will it?

Hi Shag - It is likely that the hum is video related. To verify, disconnect the cable feed into the cable box or satellite receiver. If the hum still persists call me toll free at 1.866.244.8796.

I had a ground loop hum not too long ago, found the source to be that our lawn guy had bumped the ground wire at the connection to the home ground rod ... a quick and determined reconnection of the wire to the ground rod rectified the ground loop.

I'd check all cable and outside home grounding sources.

Also, whenever I had grounding issues involving the cable coax the hum came through the 80s and not the 600....whether or not it makes any difference where the hum comes from, I don't know.

Lawn Guy?

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I don't have cable or satellite connected up to any of my components. Not even the TV.

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You can get an isolation transformer for audio signals as well. Its not a notch filter, Just a transformer. Obviously the quality will matter as with any type of transformer inline with your signal.

Here's one I would like to get for use with my computer but just cant justify the money at the time.

http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=245-875