Onkyo HT-R340 feedback noise when all 3 front speakers connected

[Skylark]

Hi all,

I'm new here and am not an audiophile, but I don't know where else I could post this kind of question. Sorry in advance for the long post, but I have tried to do my homework and try as many things as possible so I can give you a clear picture of the problem and what I've tried.

I have a pretty weird problem with my receiver and speakers. First the models:

Onkyo HT-R340
Speakers came with it
Front Left and Right: SKF-340F 120W 6ohms
Center: SKC-340C 120W 6ohms
Back Left + Right: SKS-340S 120W 6ohms

The problem is that whenever the three front speakers (left, right and center) are connected, there is a feedback humming sound and I can hear indistinct voices through it, as if I were hearing the radio. If I disconnect any one of the front speakers, the hum disappears. It can be any of the three.

Things I have tried that didn't change anything:

• I tried replacing one of the speaker cables (the center one) with another one. Didn't work. All cables are in good condition with no visible breaks or anything.
• I have disconnected everything, it happens with <b>only</b> the three front speakers and power connected. No sources connected to the receiver at all.
• I have also tested with all my other equipment (cable box, TV, consoles, DVD/BD player) unplugged from the power outlets, and all other wall plugs (network, cable for internet and digital cable TV, telephone) disconnected.
• I tried putting more distance between the three front speakers, but even at the width of my room (and the center speaker evenly between the left and right) it didn't change anything.

But, I did try one thing that worked, and that puzzled me. At the receiver, I tried plugging the Front Left speaker's cable into the Rear Right output, and vice versa. The hum disappeared. But, if instead of switching the connections at the receiver, I switched the speakers (i.e. the Rear Right speaker plugged into the Front Left output using the Front Left cable) then the hum was still there.

Also, the hum doesn't get louder when I increase the volume. It just stays the same (but is too loud to be ignored over an audio source playing at normal volume).

I'm probably going to go buy a reel of speaker cable tomorrow and replace all the speaker cables, but I'm dubious as to whether that'll change anything.

Could anyone suggest what the problem might be?

Thanks in advance,

Skylark

 

[TLS Guy]

Hi all,

I'm new here and am not an audiophile, but I don't know where else I could post this kind of question. Sorry in advance for the long post, but I have tried to do my homework and try as many things as possible so I can give you a clear picture of the problem and what I've tried.

I have a pretty weird problem with my receiver and speakers. First the models:

Onkyo HT-R340
Speakers came with it
Front Left and Right: SKF-340F 120W 6ohms
Center: SKC-340C 120W 6ohms
Back Left + Right: SKS-340S 120W 6ohms

The problem is that whenever the three front speakers (left, right and center) are connected, there is a feedback humming sound and I can hear indistinct voices through it, as if I were hearing the radio. If I disconnect any one of the front speakers, the hum disappears. It can be any of the three.

Things I have tried that didn't change anything:

• I tried replacing one of the speaker cables (the center one) with another one. Didn't work. All cables are in good condition with no visible breaks or anything.
• I have disconnected everything, it happens with <b>only</b> the three front speakers and power connected. No sources connected to the receiver at all.
• I have also tested with all my other equipment (cable box, TV, consoles, DVD/BD player) unplugged from the power outlets, and all other wall plugs (network, cable for internet and digital cable TV, telephone) disconnected.
• I tried putting more distance between the three front speakers, but even at the width of my room (and the center speaker evenly between the left and right) it didn't change anything.

But, I did try one thing that worked, and that puzzled me. At the receiver, I tried plugging the Front Left speaker's cable into the Rear Right output, and vice versa. The hum disappeared. But, if instead of switching the connections at the receiver, I switched the speakers (i.e. the Rear Right speaker plugged into the Front Left output using the Front Left cable) then the hum was still there.

Also, the hum doesn't get louder when I increase the volume. It just stays the same (but is too loud to be ignored over an audio source playing at normal volume).

I'm probably going to go buy a reel of speaker cable tomorrow and replace all the speaker cables, but I'm dubious as to whether that'll change anything.

Could anyone suggest what the problem might be?

Thanks in advance,

Skylark

Thank you for your excellent description of your problem. As a result I can tell you exactly what your problem is.

Your problem is radio frequency penetration via the speaker leads.

You must live fairly close to a radio station or TV station transmitter.

The problem comes about by the speaker leads acting as an antenna. They then feed the signal back to the speaker output connectors. That feeds the signal via the negative feedback circuits in your receiver to the high gain section of the power amplifier section. That is why it does not change with volume. Emitter base junctions at those high gain stages are acting as a radio detector just like in a radio, and you hear the station and a rectified version of the carrier signal. This is prone to happen on units whose design is less than stellar.

The first thing to try is to shorten your speaker leads as much as possible.

If that fails you need to build RF traps.

Get a ferrite rod like this, one for each speaker.

Then get some 15 G copper wire.

Now put 10 turns of the copper wire round each ferrite rod.

With a sharp knife peel off the enamel insulation from the copper wire ends.

Solder one end of each coil to the +ve speaker speaker lead at the receiver end. Cover it all with electrical tape except for the other ends of the coils which you will connect to each +ve speaker terminal.

If that does not work you only have two remaining options.

1). Buy a higher quality receiver.

2). Move to a location much further from radio and TV stations masts.

 

[Skylark]

Thank you for your excellent description of your problem. As a result I can tell you exactly what your problem is.

Great, that's what I wanted to hear!

The first thing to try is to shorten your speaker leads as much as possible.

Hm, I started having this problem when I tried to run my back speakers around the room to actually get them behind the sofa, so yeah I might try that as a first step. But this happens even when the back speakers are disconnected, and the front speaker cables are pretty short already (less than 10 feet each for all 3) so I don't know if this will work.

Now just a few questions about the other solution you suggested, thanks for the links but I have some questions the descriptions don't answer.

If that fails you need to build RF traps.
Get a ferrite rod like this, one for each speaker.

Is that rod solid? Or is it hollow so I would pass the original speaker cable through it? I can't see from the picture.

Then get some 15 G copper wire.

Is that single-conductor solid insulated copper wire? Just making sure.

Now put 10 turns of the copper wire round each ferrite rod. With a sharp knife peel off the enamel insulation from the copper wire ends. Solder one end of each coil to the +ve speaker speaker lead at the receiver end. Cover it all with electrical tape except for the other ends of the coils which you will connect to each +ve speaker terminal.

So the copper wire should run the same length and parallel to the speaker cable, and connect to the positive terminals at each end (along with the positive lead of the speaker cable), with the ferrite rod somewhere between the two rolled up in 10 turns of the copper wire? Is that right?

If that does not work you only have two remaining options.
1). Buy a higher quality receiver.
2). Move to a location much further from radio and TV stations masts.

1 is unlikely to happen in the near future... And 2 even less. So I'll try your solutions and see what happens.

Do you think I can buy speaker cable that would already be adequately shielded to prevent this? It's just that I have no way of knowing for sure that I'm doing things right, and it might cost more than just buying good cables ($3.95 x 6 + $7.95 = $31.65, and that's assuming I have long enough of the copper cable in that reel - they don't mention the length - and that I don't pay higher prices for all that here...)

Thanks a lot for your answer!

 

[TLS Guy]

Great, that's what I wanted to hear!



Hm, I started having this problem when I tried to run my back speakers around the room to actually get them behind the sofa, so yeah I might try that as a first step. But this happens even when the back speakers are disconnected, and the front speaker cables are pretty short already (less than 10 feet each for all 3) so I don't know if this will work.

Now just a few questions about the other solution you suggested, thanks for the links but I have some questions the descriptions don't answer.



Is that rod solid? Or is it hollow so I would pass the original speaker cable through it? I can't see from the picture.



Is that single-conductor solid insulated copper wire? Just making sure.



So the copper wire should run the same length and parallel to the speaker cable, and connect to the positive terminals at each end (along with the positive lead of the speaker cable), with the ferrite rod somewhere between the two rolled up in 10 turns of the copper wire? Is that right?



1 is unlikely to happen in the near future... And 2 even less. So I'll try your solutions and see what happens.

Do you think I can buy speaker cable that would already be adequately shielded to prevent this? It's just that I have no way of knowing for sure that I'm doing things right, and it might cost more than just buying good cables ($3.95 x 6 + $7.95 = $31.65, and that's assuming I have long enough of the copper cable in that reel - they don't mention the length - and that I don't pay higher prices for all that here...)

Thanks a lot for your answer!

Changing speaker wire is not likely to help, and speaker wire should not be shielded. However some reasonable quality speaker wire from Monoprice or Blue Jeans cable is worth a try.

The ferrite core is solid and the copper wire is solid core..

You wind the copper round the outside of the ferrite core round its axis to make an inductor. After winding I would cover the coil in a good glue to bond the copper to the rod.

The choke (inductors you build) go in series with the +ve speaker leads at the receiver end.

Make sure you insulate everything well with electrical tape so you don't create shorts to ground.

One other issue: - the fact that that receiver behaves that way is a violation of FTC rules. These days components are supposed to be impervious to this type of RF penetration. So basically you are entitled to turn them in. There is far too much of this type of junk getting onto the market.

One other thing someone might be able to to for you with a circuit of your unit, is to place 10pf caps across the inputs where the negative feedback circuit re enters the amp boards.

This sort of problem used to be much more prevalent years ago, and led to a lot of conflict with the broadcast industry. That is why there are regulations to make manufacturers take steps to prevent this type RF penetration. It is easily prevented with proper design, but adds a few cents to each unit.

 

[Skylark]

Thanks again for taking the time to reply thoroughly and inform a neophyte such as myself.

Changing speaker wire is not likely to help, and speaker wire should not be shielded. However some reasonable quality speaker wire from Monoprice or Blue Jeans cable is worth a try.

OK, I think I'll try that first, if it works it'll be less hassle and will look better in general...

The choke (inductors you build) go in series with the +ve speaker leads at the receiver end.

Oh, so I only need just enough copper cable to wind 10 times around the rod and have a bit extra, and I connect the receiver end of the + speaker wire on one end and connect the other end into the receiver's terminal (where the speaker wire should go)?

OK that sounds more reasonable, I thought from your initial description that the copper wire had to run the length of the original speaker cable so it would plug into the receiver AND the speaker...

One other issue: - the fact that that receiver behaves that way is a violation of FTC rules. These days components are supposed to be impervious to this type of RF penetration. So basically you are entitled to turn them in. There is far too much of this type of junk getting onto the market.

By turn them in, you mean tell the FTC or some authority that they made non-complying equipment? I'm in Canada, so I'm not sure what I can do with the FTC, but in any case, might I be able to send the unit in and get it replaced, even if the warranty is expired? From my point of view that would be a better deal!

One other thing someone might be able to to for you with a circuit of your unit, is to place 10pf caps across the inputs where the negative feedback circuit re enters the amp boards.

Hm, I'll ask one of my friends who knows about electronic circuits, but if I can get a unit that doesn't have this problem without having to tinker with it I'd prefer that... Sorry but I'm just a consumer on these types of things. I'll be glad to replace a motherboard on a PC or fix some obscure bugs in some open source software, but I don't tinker with home electronics at all...

This sort of problem used to be much more prevalent years ago, and led to a lot of conflict with the broadcast industry. That is why there are regulations to make manufacturers take steps to prevent this type RF penetration. It is easily prevented with proper design, but adds a few cents to each unit.

I didn't get the impression it was a cheap unit at all when I bought it, it seemed quite good, and not at the cheap end of the price range for a 5.1 PLII/DTS/DD receiver, but then it's obvious I'm not an expert. I'll try to be more careful and read more reviews in the future.

Thanks again!

 

[TLS Guy]

Thanks again for taking the time to reply thoroughly and inform a neophyte such as myself.



OK, I think I'll try that first, if it works it'll be less hassle and will look better in general...



Oh, so I only need just enough copper cable to wind 10 times around the rod and have a bit extra, and I connect the receiver end of the + speaker wire on one end and connect the other end into the receiver's terminal (where the speaker wire should go)?

OK that sounds more reasonable, I thought from your initial description that the copper wire had to run the length of the original speaker cable so it would plug into the receiver AND the speaker...



By turn them in, you mean tell the FTC or some authority that they made non-complying equipment? I'm in Canada, so I'm not sure what I can do with the FTC, but in any case, might I be able to send the unit in and get it replaced, even if the warranty is expired? From my point of view that would be a better deal!



Hm, I'll ask one of my friends who knows about electronic circuits, but if I can get a unit that doesn't have this problem without having to tinker with it I'd prefer that... Sorry but I'm just a consumer on these types of things. I'll be glad to replace a motherboard on a PC or fix some obscure bugs in some open source software, but I don't tinker with home electronics at all...



I didn't get the impression it was a cheap unit at all when I bought it, it seemed quite good, and not at the cheap end of the price range for a 5.1 PLII/DTS/DD receiver, but then it's obvious I'm not an expert. I'll try to be more careful and read more reviews in the future.

Thanks again!

You have the hang of it now. I bet Canada has something similar to the FTC rules. In the EEC the rules are even more draconian, and a manufacturer can be banned from importing all product for these sorts of infractions.

If you replace your receiver, you will get one of the same type so that won't help. I see here that rig sold for $350 and you can't make anything that is any good for that money.

Basically HTIBs are bad news all around. Consumer reviews are worthless by the way.

 

[Skylark]

If you replace your receiver, you will get one of the same type so that won't help. I see here that rig sold for $350 and you can't make anything that is any good for that money.

I think I spent more than that, and it was about 4 years ago so it has probably come down. What's a good price range then? I don't want to spend a grand on a receiver. I don't even use any of the inputs on it, my HDTV has more than enough HDMI inputs and the receiver only has a few component and composite inputs... I only use it to feed sound to the 5.1 speakers, by connecting it my TV's digital audio output... So basically the only things plugged into the receiver are one digital audio cable and the 5 speakers + sub.

If you have anything to suggest for that kind of use at a reasonable price I might consider changing the receiver, but possibly keeping the same speakers... It's a pretty small room (15x13 feet I think) so I don't need a lot of power.

Basically HTIBs are bad news all around. Consumer reviews are worthless by the way.

HTIB? Home Theater In a Box? I didn't think my unit fell into that category, it was just the receiver + speakers. No DVD, nothing else...

What's a consumer to use other than reviews in order to get information before buying? It's hard to get hands-on experience with multiple units before buying anything...

Sorry for sounding like a newbie, but I'm not a connaisseur, just someone who wants to watch movies and play my games. I think even at lower price ranges for non-expert users, I should be able to expect acceptable sound (I don't have really sensitive ears, but this hum is really loud).

Thanks again for your help.

 

[TLS Guy]

I think I spent more than that, and it was about 4 years ago so it has probably come down. What's a good price range then? I don't want to spend a grand on a receiver. I don't even use any of the inputs on it, my HDTV has more than enough HDMI inputs and the receiver only has a few component and composite inputs... I only use it to feed sound to the 5.1 speakers, by connecting it my TV's digital audio output... So basically the only things plugged into the receiver are one digital audio cable and the 5 speakers + sub.

If you have anything to suggest for that kind of use at a reasonable price I might consider changing the receiver, but possibly keeping the same speakers... It's a pretty small room (15x13 feet I think) so I don't need a lot of power.




HTIB? Home Theater In a Box? I didn't think my unit fell into that category, it was just the receiver + speakers. No DVD, nothing else...

What's a consumer to use other than reviews in order to get information before buying? It's hard to get hands-on experience with multiple units before buying anything...

Sorry for sounding like a newbie, but I'm not a connaisseur, just someone who wants to watch movies and play my games. I think even at lower price ranges for non-expert users, I should be able to expect acceptable sound (I don't have really sensitive ears, but this hum is really loud).

Thanks again for your help.

Anything with a receiver and speakers in a box is HTIB.

Something like this would fit your needs.

It is much better to connect everything to the receiver and output from the receiver to the TV.

In box systems, the receivers are low end and the speakers even worse.

So shopping for some nice bookshelves and a decent sub would improve your system greatly. Then with a Blue Ray player you would be all set. HD TV with the latest audio codecs.

 

[Skylark]

Anything with a receiver and speakers in a box is HTIB.

Ah ok, I didn't know the terminology.

Something like this would fit your needs.

The link didn't come through... It just went to http something%20like%20this%20would%20fit%20your%20needs. You can always just post the make and model and I'll look it up on Canadian shopping sites.

It is much better to connect everything to the receiver and output from the receiver to the TV.

In box systems, the receivers are low end and the speakers even worse.

So shopping for some nice bookshelves and a decent sub would improve your system greatly. Then with a Blue Ray player you would be all set. HD TV with the latest audio codecs.

I think we're really not the same kind of user. The system I have, playing Kung Fu Panda or Sherlock Holmes (I already have a blu-ray player, a Sony) or my XBox360, all sound great to my ears. Much better than my TV's speakers. If I could just get rid of that noise I'd be set. So I think I'll try to find those ferrite rods and see if that can help. (on that subject, will I find them in a renovation center or do I have to find an electronics parts/supplies store?)

To me, the only difference between plugging all sources into the TV and outputting digital audio to the receiver, and plugging all sources into the receiver and outputting HDMI to the TV, is replacing an RCA (coax digital out) cable by an HDMI cable. The RCA I have, the HDMI would cost me 20 bucks or more (plus the receiver, my current one only does component, no HDMI at all). There's no signal loss in digital audio, so I don't see the practical difference other than the cable. And I don't really mind about audio codecs as long as the sound plays well enough (I have PLII, DTS and Dolby Digital, which sound good enough to me).

I'd probably hear a difference with a higher quality system and speakers, but I think what I have fits my needs. As I said, computing is more my thing, I'll want the latest video card and I'll upgrade my CPU every year, but I don't do the same for home electronics. I hope you can respect the difference in point of view and different requirements (and different budget too)... It's a matter of choices.

Thanks a lot for helping.

 

[TLS Guy]

Ah ok, I didn't know the terminology.



The link didn't come through... It just went to http something%20like%20this%20would%20fit%20your%20needs. You can always just post the make and model and I'll look it up on Canadian shopping sites.



I think we're really not the same kind of user. The system I have, playing Kung Fu Panda or Sherlock Holmes (I already have a blu-ray player, a Sony) or my XBox360, all sound great to my ears. Much better than my TV's speakers. If I could just get rid of that noise I'd be set. So I think I'll try to find those ferrite rods and see if that can help. (on that subject, will I find them in a renovation center or do I have to find an electronics parts/supplies store?)

To me, the only difference between plugging all sources into the TV and outputting digital audio to the receiver, and plugging all sources into the receiver and outputting HDMI to the TV, is replacing an RCA (coax digital out) cable by an HDMI cable. The RCA I have, the HDMI would cost me 20 bucks or more (plus the receiver, my current one only does component, no HDMI at all). There's no signal loss in digital audio, so I don't see the practical difference other than the cable. And I don't really mind about audio codecs as long as the sound plays well enough (I have PLII, DTS and Dolby Digital, which sound good enough to me).

I'd probably hear a difference with a higher quality system and speakers, but I think what I have fits my needs. As I said, computing is more my thing, I'll want the latest video card and I'll upgrade my CPU every year, but I don't do the same for home electronics. I hope you can respect the difference in point of view and different requirements (and different budget too)... It's a matter of choices.

Thanks a lot for helping.

I would order your parts on line. You could scrounge some ferrite rods from the antennas of old radios, take off the coils and cut the ferrite to length with a hack saw. You will need five rods in all.

If that HTIB meets your needs now well and good, although from requests on those forums those units don't seem very long lived.

Sorry about the link, lets try again.

Take a look at this one.

 

[Skylark]

I would order your parts on line. You could scrounge some ferrite rods from the antennas of old radios, take off the coils and cut the ferrite to length with a hack saw. You will need five rods in all.

Or does this look like what you had in mind? (first 6 products at the top, the specs differ for each)

They don't say the length of the ferrite rods, but they're all under $2 CAN each for the rod and coiled copper wire, versus the rods at $3.95 US each and copper wire at $7.95 US you linked to before...

(yay I can post links now! )

Sorry about the link, lets try again.

Take a look at this one.

Looks nice, 4 HDMI is what I need (and what my TV has), and other inputs I need (one component for my DVD changer, some composites for old consoles and VCR). I'll keep that in mind when I want an upgrade. And I'll also keep in mind your advice concerning speakers and sub, I can always gradually upgrade in the future.

Note that I'm not married to Onkyo as a brand, it could have been any brand...

Thanks again.

 

[TLS Guy]

Or does this look like what you had in mind? (first 6 products at the top, the specs differ for each)

They don't say the length of the ferrite rods, but they're all under $2 CAN each for the rod and coiled copper wire, versus the rods at $3.95 US each and copper wire at $7.95 US you linked to before...

(yay I can post links now! )



Looks nice, 4 HDMI is what I need (and what my TV has), and other inputs I need (one component for my DVD changer, some composites for old consoles and VCR). I'll keep that in mind when I want an upgrade. And I'll also keep in mind your advice concerning speakers and sub, I can always gradually upgrade in the future.

Note that I'm not married to Onkyo as a brand, it could have been any brand...

Thanks again.

This is the one you need, but there are none available.

They are simple to make though.

You sound like someone who would have the skills to build a nice HTPC. You should think about it.

 

[Skylark]

This is the one you need, but there are none available. They are simple to make though.

Great, thanks, I'll look around. Just curious, what did you look at to tell me that's the one I need?

You sound like someone who would have the skills to build a nice HTPC. You should think about it.

Yeah, I'd like to do that someday soon. It would be a really fun hobby project. Plus playing my PC games on my big screen would be really awesome.

Thanks a lot!

 

[Skylark]

BTW, I sent Onkyo a question regarding this feedback problem, giving them the link to this thread so they could read my full description of the symptoms. Here was their reply:

Try to spread out your cabling behind the receiver. Make sure it's not bunched up . Try using banana connectors when connecting the speaker wires into the receiver.

I'm pretty sure these two things won't help one bit, the first one because I tried separating the cables as much as possible already, and the second because the speaker connectors are clips that accept bare wire only, banana plugs won't fit.

They did reply quickly though, about 5 hours.

 

[TLS Guy]

BTW, I sent Onkyo a question regarding this feedback problem, giving them the link to this thread so they could read my full description of the symptoms. Here was their reply:



I'm pretty sure these two things won't help one bit, the first one because I tried separating the cables as much as possible already, and the second because the speaker connectors are clips that accept bare wire only, banana plugs won't fit.

They did reply quickly though, about 5 hours.

Sounds like a classic blow off!

 

[TLS Guy]

Great, thanks, I'll look around. Just curious, what did you look at to tell me that's the one I need?



Yeah, I'd like to do that someday soon. It would be a really fun hobby project. Plus playing my PC games on my big screen would be really awesome.

Thanks a lot!

Just thought that was about your budget and those receivers seem to give pretty good service judging by these forums. I'm not the best one to ask about receiver purchases. I have never owned a receiver!

 

[Skylark]

Just thought that was about your budget and those receivers seem to give pretty good service judging by these forums.

No, I meant the ferrite rod and coil. Out of the 6 at the page I sent you, what did you look at to know which one I needed? They specify different inductance (µH) and current (A), did you just pick the lowest inductance?

Anyways, seems I have to buy 100 minimum at that site, so I'll probably have a go at making my own. Thanks for all the help!

 

[TLS Guy]

No, I meant the ferrite rod and coil. Out of the 6 at the page I sent you, what did you look at to know which one I needed? They specify different inductance (µH) and current (A), did you just pick the lowest inductance?

Anyways, seems I have to buy 100 minimum at that site, so I'll probably have a go at making my own. Thanks for all the help!

Yes, that inductance was what I wanted, and if you notice it has 10 turns, like I instructed you to make yours.

 

[jostenmeat]

Skylark, forgive my intrusion, as I also wanted to pick TLS' brain. If it gets out of hand, I'll start my own thread, thanks for understanding.

TLS, I recently had to remove the entire front half of my HT, to paint a significant portion of my ceiling black (looks awesome). Since I was putting everything back again, even marked the spots, I wanted to reinvestigate the stereo performance (although it never* ever* is used in stereo). I was happy with the layout after all, with only the slightest of a hole (I mean very slight), with the center channel defeated.

However, I had buzzing from my rear speakers! The side surrounds had no buzzing. I left the subwoofer defeated the entire time.

Oh wait a second . . . the rears are ceiling mounted, and I bet the wires are running right next to my antler antenna for my OTA signal, but I doubt this would be an issue. And since I don't get any buzz when it's full mch playback, it must be an issue with my receiver?

I'll try stereo mode again in the relatively near future . . .

 

[TLS Guy]

Skylark, forgive my intrusion, as I also wanted to pick TLS' brain. If it gets out of hand, I'll start my own thread, thanks for understanding.

TLS, I recently had to remove the entire front half of my HT, to paint a significant portion of my ceiling black (looks awesome). Since I was putting everything back again, even marked the spots, I wanted to reinvestigate the stereo performance (although it never* ever* is used in stereo). I was happy with the layout after all, with only the slightest of a hole (I mean very slight), with the center channel defeated.

However, I had buzzing from my rear speakers! The side surrounds had no buzzing. I left the subwoofer defeated the entire time.

Oh wait a second . . . the rears are ceiling mounted, and I bet the wires are running right next to my antler antenna for my OTA signal, but I doubt this would be an issue. And since I don't get any buzz when it's full mch playback, it must be an issue with my receiver?

I'll try stereo mode again in the relatively near future . . .

I guess the questions are whether there is a buzz with just your receiver plugged in and nothing else connected to the receiver. It would be pretty hard to get a ground loop just involving rear speakers.

I wonder if you could have nicked some wiring? Try running speaker cables direct from your receiver to the rears and see if that stops the buzz.