Subwoofer Buzz?

Does anybody else out there get a buzz while using the LFE output hooked up to a powered subwoofer? I'm currently getting a pretty loud buzz when using the 5.1 direct input or that matter, any input that isn't sending information to the sub channel. I know what I'm typing isn't quite making sense, so please try to follow.

When I turn on my 1050, it thinks (hehe, thinking...)for a second then clicks on. (On a side note here, that click also produces a slight pop in my speakers.) After the click, it seems to search for a source. If it finds my DVD connection, using the coax input, it's happy, i.e. no noise. If I switch it to the 5.1 direct input to listen to a SACD, my subwoofer starts buzzing. If I try different inputs; the subwoofer stops the buzzing as soon as I select another input, the 1050 looks, finds nothing, and then the subwoofer begins to buzz again. Even weirder, the subwoofer will continue to buzz through a multi-channel SACD that IS sending subwoofer information.

My original thinking was either a bad connection, electrical interference, bad cable or something like that. But, none of those explain why I don't get a buzz when playing a DVD. It seems to me like the 1050 sends the buzz when it's not using the subwoofer output. But, that doesn't explain the buzz produced when the subwoofer IS working during a multi-channel SACD.

Ok, I admit it, I'm lost!!

Here's my signal path for some further info.
Sony DVP-NS500V - 1050 - shielded 3' Y cable - L/R line inputs on a Parts Express subwoofer amp - short speaker cable run to inputs on sub.

If somebody out there has any idea, please, please share it with me. This buzz is truly annoying!!

Could be as simple as a ground loop between the sub and the 950. Try plugging the sub into the same AC outlet that the 950 is plugged into temporairly and see if the buzz disappears. If your sub has a 3 prong plug, you might try a simple ground 'cheater' plug, which might correct the problem.

The fact that it comes and goes bothers me - I'd expect a ground loop to be more invariant. Does the buzz really go away or is it just masked when the sub is active?

Have you tried sending the line level LFE to the subwoofer? I'll have to check but I'm pretty sure you can just run a single low level line to your sub from LFE on those amps. The summing circuit won't care a bit. If lifting the speaker wires cleans up the signal just dial the amp xover up out of the way and do your bass management in the 1050. You might want an ICBM for the SACD.

What is your speaker configuration?



[This message has been edited by charlie (edited December 15, 2002).]

Oh, I get those coming-and-going buzzes too - but they are almost always caused by a close encounter with a pitcher of margaritas

Seriously, these are sometimes caused by some heavy load on the common power transformer (on the power pole) that you share with others in your immediate area. Something like an air conditioner, space heater etc. Also, if you have any light dimmers, these can sometimes cause buzz when the lights are dimmed down, but not fully off. Devices with high internal impedances are most succeptable to this, since the waveform that goes to the lightbulb is very 'spikey', which has a lot of high frequency components. If this is your problem, the cure is autotransformer light dimmers, or sometimes a good power line filter, like the TrippLite "Isobar". I think there might also be some SCR dimmers that don't radiate buzz too, but I don't have any names to give you. I use autotransformers.

[This message has been edited by soundhound (edited December 15, 2002).]

[This message has been edited by soundhound (edited December 15, 2002).]

Thanks for the ideas fellas. All of them sound pretty good. Here's what I've tried so far.

1. Put the 1050 and sub on the same circuit. Still got the buzz.
2. Put a ground lift on the sub amp plug. Still got the buzz.

I'm thinking also that it has to do with the lights and the electrical system in my room. I have a flourescent light as my main light which emits a wonderful buzz. I always have the light off when using the system. Bad NYC electricity wouldn't surprise me.

I tried going with a single line level in also. The volume went down but when turned back up to compensate, the buzz returned at the same level. The crossover on the amp is turned all the way up to make use of the crossover on the 1050.

Yes, the buzz in still there when using the direct inputs and information is being sent to the sub. This and the fact that I don't get the buzz while using a dvd is by far the weirdest part.

About the only things left to try are to try to plug something else directly into your sub, such as the line outs of your CD player and see if you still get the buzz. If you try this, make sure that the CD player is truly freestanding and not connected to anything else. If there is no buzz, then the finger points back to the 950/interaction with sub.

You might also try running a single strand of wire from the chassis (under a screw head that holds on the lid) of the 950 to the chassis of the sub (something metal). This would tell you if it is a ground loop or not. Try to lift the line connections while you're at it and see if the buzz changes.

One last thing to check is if the metal of the 950 chassis is touching the metal chassis of one of the other components, maybe through some metal in your equipment rack.

Beyond that, you are running out of options. If your lights are off, then they would not give out any interferrence. There also might be something else in your house that is injecting crap into the AC line. Refridgeratiors, washers etc can do this. If you have any X-10 modules, these can also be the culprit.

You might also try plugging the LFE output of the 950 into some other amplifier channel and see if it still buzzes. There is the possibility that the 950's LFE output may be defective, maybe a bad solder connection at the ground of the output jack or something like that.

If all this fails, it's got to be demons, for which I can offer no advise

[This message has been edited by soundhound (edited December 16, 2002).]

Soundhound, you keep saying 950 . . . he has a 1050.

Larry

Same principles involved

I found the culprit!! I had a stereo 1/8" to stereo RCA connector coming out of my M-Audio Sonica connected to my AUX in jacks. Upon disconnecting this cable, the buzz went bye-bye!! The Sonica also has a optical output that is working fine.

Oh well, hopefully buzz does not return. Thanks to everybody, especially soundhound and charlie, for their ideas. If one of you guys wants to post the reasoning why that connection caused the buzz....

Sounds like you had a ground loop between your M Audio device and the 1050. Why this would manifest it's self in the LFE to sub circuit is a mystery. Glad to hear you traced it.

I'm curious why it comes and goes. Is it random, or only present when the m-Audio is on or something?

I just received my SVS sub and was very dismayed at the buzz I was getting. I have a 1050 with a Pioneer DV-05 DVD player. The buzz would start as soon as a DVD or CD was loaded into the Pioneer (DTS or Pro-Logic, all produce buzz). I started randomly unplugging cables until I found that the s-video cable was the culprit. I do not have an extra s-video cable to test the cable but I found it very odd to have the buzz come from a video cable. The SVS is plugged in at the other end of the room but unsure if it is a separate circuit. I do not have video going to the 1050 any more and use the component straight to the TV. Still it is another odd cable causing the buzz.