Subwoofer Pop/Buzz When Low Power (1 Viewer)

[scottay]

Hi all,

My Martin Logan Dynamo 500 subwoofer has been acting up for a while, and I'm at the point that I need to find a solution. I purchased it from Best Buy in August 2012. Since then I've replaced every other piece in my setup (new receiver, speakers, Blu-Ray player, etc). Also, I recently moved, so I've got a new cable, power strip, etc, so all that is different as well. I can't remember exactly when it started, but I replaced my receiver last July and I know it was a problem prior to that.

Ok, enough history, here's my problem:
Just about every time it goes into standby (there is no permanent on, just off and auto) it will buzz. It's not subwooer hum. It's a very distinct, loud, obnoxious, low, rumbling, buzzing noise. Also, it seems like when it's under very light power (ie. at night when I have the volume low) it will randomly "pop." I share walls with neighbors (less now than before in the apartment, but it's still a townhouse not a house), and the power is generally low late at night, so when it does this I'm sure my neighbors are thrilled.

I've done a lot of searching the web and I've seen threads on ground loop and appliances possibly being the issue, but seeing as how everything is setup at a new place I don't think that's likely. At the old place it was on the same power strip as the receiver. At the new place it's on a totally different outlet. I had to replace the cable with a longer one, so it's not a bad cable. It did it with the old receiver and the new, so I don't think it's the receiver sending wonky signals to it. It doesn't matter what source I have it on. I've unplugged the coax cable and it still pops randomly, but I don't get the buzz.

I hope I've given enough info to help provide a solution. Any help would be much appreciated.

Thanks in advance!

 

[schan1269]

On phone, so I can't look...If the Dynamo has high level, switch to that(Not permanently) to see if either problem goes away. Just set it along the front speakers as all you are doing this for is ruling out a dying amp.

 

[schan1269]

Of course, reset the AVR as "no sub" which will route the .1 into the front channel.

 

[scottay]

Thanks for the reply.

Not sure exactly what you mean.

The sub has 2 switches: Phase and Crossover (LFE vs. variable). 2 knobs: Level and LPF (which doesn't do anything with LFE). 2 plugs: Left and Right, right acting as LFE in, which is where I have my coax.

 

[schan1269]

I'm in a 2g zone...but I did find a pic that didn't take an eternity...No high level(high level is speaker wire in and out for use where there is no subwoofer output).If your cable is shielded(coax) and you have random pops...usually that means the sub amp itself is not properly shielded(mass market item...manufacturing oops happen).Short of a bench test at BB(which might be how ML warranty is handled anyway), who knows.But two places to live, same issues...leads to it having an issue.