Strange Buzz Problem

R12y6a86n · Sep 20, 2006

I'm having a very odd problem. I have a Grotto subwoofer hooked up to a Denon AVR-3805 receiver, and use a single subwoofer cable from the receiver to the subwoofer.

Today, I suddenly noticed buzzing coming from my main speakers, and I was able to locate the problem to my subwoofer being plugged in (power plug just into the power strip). When I unplugged the sub, the buzzing stopped. When I plugged the power back in, the buzzing started back up again. I also tried the subwoofer on standby mode, but that did not stop the buzzing. Thinking maybe the problem was related to it was the outlet it was plugged into, I tried different outlets, but the other speakers still buzzed whenever the sub was getting power.

Interestingly, the buzzing does not increase or decrease when I turn the volume up or down on my receiver. I was under the impression that the LFE out that I use was one way, so I was suprised when I found the Grotto to be the problem!

At around the same time the buzzing problem started, I also noticed much reduced bass when I tried playing music. The Grotto isn't silent when there is bass in music, but not nearly what it should be.

Does anyone have any ideas about what happened here? Before I take it in for service, is there anything I should try? Do you think this is a problem with my sub at all, or is it maybe a receiver problem (although it would be hard for me to believe since it stopped when I unplugged power to the sub)?

Thanks for any ideas you may have!!!

Matten Logan · Sep 20, 2006

sounds like a classic ground loop problem. I think that you outlet is not wired properly or the circuit that that outlets on is not properly grounded. Call an electician.

wink · Sep 20, 2006

R12y6a86n said:
Today, I suddenly noticed buzzing coming from my main speakers, and I was able to locate the problem to my subwoofer being plugged in (power plug just into the power strip). When I unplugged the sub, the buzzing stopped. When I plugged the power back in, the buzzing started back up again.

I would try switching out my power strip before anything else....Could possibly be a ground problem there.

roberto · Sep 20, 2006

Matten Logan said:
sounds like a classic ground loop problem. I think that you outlet is not wired properly or the circuit that that outlets on is not properly grounded. Call an electician.

Agreed here, try a cheater plug, sometimes this work...happy listening,
Roberto.

MiTT · Sep 20, 2006

As far as your reduced bass output with music is concerned...

I may be wrong, but if you are only driving the sub off of the LFE output from your receiver, you won't be getting much content from non-DD/DTS content. That is to say that if the source is only 2 channel vs 5.1 or 7.1 content; there isn't any .1 signal to send to the sub from the LFE output. In my home theater system (Denon Receiver & 2910 Universal player, Velodyne sub, Gallo Acoustic Micro's) I run both an LFE connection as well as running speaker cable to the sub's speaker level connections, then on to the mains. Works well for both HT and stereo.

I agree with all above on the buzz, sounds like a ground loop problem. Do you have your cable tv signal connected to your receiver? Cable providers are notorious for not properly grounding their own signals. There are a number of noise eliminator devises out there, and/or you could consider a good power conditioner (PS Audio, Hydra, Richard Gray etc).

R12y6a86n · Sep 20, 2006

Thanks!

Well, I think you guys are right about the outlet being bad. I had actually tried another outlet in the room before writing in my question, but I'm thinking now that maybe the whole circuit has a problem. I got one of those orange extension cords and started plugging into different outlets throughout the house, and finally found a good one in the basement. Looks like I better find a good electrician if I don't want a cord running through my house.

I'm not sure if the bass is quite what it used to be, but it could be that long orange extension cords aren't the best for this.

Hope that bad power didn't do any damage to my equipment. So much for the Monster power filter things.

I can't thank you guys enough for writing in! You're the best.