All speakers are humming

tritty10

Standard Member
Hi there,

I've read a lot of forums to try and find a solution to my problem but haven't found anything quite similar to mine. When I have everything turned on (50" plasma TV, HDPVR cable box, Pioneer receiver, 7.1 speaker system) I have an annoying hum in every one of my speakers...I've followed other suggestions and unplugged everything to diagnose the problem and have found that the problem is my TV. When I turn my TV off and have everything else on the speakers are perfect, no humming at all. When I turn the TV back on the humming returns.

I've read solutions regarding changing outlets (didn't work), or a cable box ground isolator (the problem is still there during movies when the cable box is turned off) so I need other suggestions. This seems to be a common problem so I'm hoping there is a common solution.

To give a little more information, I have everything hooked up with HDMI cables. So an HDMI cable from the cable box to the receiver, an HDMI cable from the ps3 to the receiver, and an HDMI cable from the receiver to the TV.

Any help would be greatly appreciated!! This is driving me nuts!!
 

mickbirch2000

Well-known Member
What happens if you disconect the HDMI from your cable box with the TV on? does the hum go?
If it does then its likely some sort of earth loop problem via the cable service, if not then its likely caused by radiation from the plasma screen & only increasing the physical distance between your screen & your other bits of kit may be the only cure.
 

Mark.Yudkin

Distinguished Member
(the problem is still there during movies when the cable box is turned off)
...
have found that the problem is my TV
If it's the common RF-fed ground loop, as implied, it makes no difference whether the cable box is turned on or off: on / off switches do not break ground.

Unplug all aerial leads for the radio and TV feeds: aerial, satellite, cable, everything, from the back of all devices you own, regardless of connectivity. You should now be totally unable to listen to the radio or watch TV. Does it hum (you said no, but you also contradicted the finding)?

If that does eliminate the hum, get one of these per connection that you disconnected above. This is for coax connections, if you have F-type connectors you'll need the corresponding version. You should be able to find these in your local electrical outlet.
 

tritty10

Standard Member
Thanks for the reply Mark. The buzz is only present when the TV is turned on. If I shut off the TV and leave everything else on (the receiver and the cable box) so I'm still listening to the TV show through my speakers, the sound is perfect. Only when I turn the tv back on do I get the buzz in every single speaker. Seems like a power cable interference or something but I've tried moving the TV cable and that did nothing. Not sure what else to try!!
 

tritty10

Standard Member
What happens if you disconect the HDMI from your cable box with the TV on? does the hum go?
If it does then its likely some sort of earth loop problem via the cable service, if not then its likely caused by radiation from the plasma screen & only increasing the physical distance between your screen & your other bits of kit may be the only cure.

I unplugged the HDMI from the cable box (and unplugged the cable box too) so the TV was still physically on but there was no picture being produced and the buzz is still in all the speakers.

It won't be easy to try and move my tv away from my receiver as you suggest but I'll give that a shot to see if that helps.
 

llama

Active Member
How long has it done this?

What model is your TV, Amp, PVR?

The PS3 has an IEC lead, which should be earthed then... I saw no Double Insulated symbol on the sticker of an America one.

From experience the Pioneer Amp's have a IEC plug with no earth, so the only thing that I can think of is this:

The subwoofer for the 7.1 system is grounded, and so is the TV. You need only 1 earth connection to the whole system ideally. If the sub and TV are on different ring mains (assuming you live in the UK) this could be causing the problem.

I know this sounds really odd, try disconnecting the subwoofer pre out from the amplifier, and see what happens.

Reason I say this is because the sub lead will be signal + ground, which could carry the interference straight back to the amplifier.

If that doesn't solve the problem then perhaps:

1) the PS3 is grounded, but not to the same socket (or ring) as the TV

2) the amplifier may be grounded.

I have seen this problem before using a grounded power amplifier for a subwoofer that had no internal amp, and a Pioneer AX2 iirc, when the ground from the sub-preout was connected the 2 front speakers on the amp buzzed, when the screaning was broken the problem went away.

Hope to help
 

tritty10

Standard Member
How long has it done this?

What model is your TV, Amp, PVR?

The PS3 has an IEC lead, which should be earthed then... I saw no Double Insulated symbol on the sticker of an America one.

From experience the Pioneer Amp's have a IEC plug with no earth, so the only thing that I can think of is this:

The subwoofer for the 7.1 system is grounded, and so is the TV. You need only 1 earth connection to the whole system ideally. If the sub and TV are on different ring mains (assuming you live in the UK) this could be causing the problem.

I know this sounds really odd, try disconnecting the subwoofer pre out from the amplifier, and see what happens.

Reason I say this is because the sub lead will be signal + ground, which could carry the interference straight back to the amplifier.

If that doesn't solve the problem then perhaps:

1) the PS3 is grounded, but not to the same socket (or ring) as the TV

2) the amplifier may be grounded.

I have seen this problem before using a grounded power amplifier for a subwoofer that had no internal amp, and a Pioneer AX2 iirc, when the ground from the sub-preout was connected the 2 front speakers on the amp buzzed, when the screaning was broken the problem went away.

Hope to help


Thanks for the reply. I will give you more detail regarding my set up. My TV is a Panasonic Viera 50" plasma (TH-50PX77U), the receiver is a Pioneer (VSX-1018ah), and the cable box is an HDPVR Motorola through my local cable company (Shaw Cable, I'm actually located in Canada).

The TV (3 prong), receiver (3 prong), ps3 (2 prong), and cable box (2 prong) all are connected to a power bar. The sub (2 prong) is on the other side of the room and is plugged into a different outlet. I've tried disconnecting the sub from the system and the buzzing still exists. I've troubleshooted the problem to be the TV, without a doubt. Everything is perfect if the TV is turned off.

I've recently moved and bought a new tv stand which is primarily glass so I'm curious if the "plasma interference" comment above is the problem. Is there any validity to this solution? Have plasma TV's been known to cause interference with other electronic devices? I can't recall this being a problem at my old place so I'm quite puzzled why this is happening.
 

vtecsilver

Standard Member
Did you say you had tried disconnecting the (cable TV) coax cable from the back of your cable TV box?
 

tritty10

Standard Member
Did you say you had tried disconnecting the (cable TV) coax cable from the back of your cable TV box?

yes, I've tried that. As long as the TV is physically on, whether there is a picture signal going to it or not, the buzzing is still there in all my speakers. Nothing seems to be working for me, it couldn't be the HDMI cable going from the TV to the receiver could it? I'm running out of ideas here...
 

tritty10

Standard Member
Not sure if anyone is still reading this, but I'm going to update what I know anyway...it seems as though all 7 of my speakers are picking up the buzzing that my TV makes when it's turned on....if I listen behind my TV you can hear an annoying buzzing, but it isn't loud enough to be notice from my seating area...when you change the picture settings (vivid, standard, cinema, etc) you can hear a change in the frequency of the buzzing in the TV...well, when I do the same picture setting changes with my ear to my speakers you can hear the same change in frequency, so my speakers are picking up the buzzing my TV is making...not sure if this will spark any new ideas but again, any help is definitely appreciated...

Annoyed
 

Mark.Yudkin

Distinguished Member
How close is the TV to the audio electronics?
 

xmb

Well-known Member
This sounds like it might be interference from the TV switch mode power supply traveling down the HDMI lead into your amplifier. As your TV has an earth connection in the plug it may be that you are suffering a broken connection to ground. This causes the leakage current (and PSU interference) to travel down the HDMI lead into the amplifier rather than into the earth wire. This also defeats any mains filters inside the TV.

You need to check both your mains outlet sockets in the wall and any extensions that are used are correctly earthed using a tester designed to check wiring (normally a unit like this you can plug in and has three lights to indicate all the wiring is correct). Also check the IEC lead to the TV has a proper earth (maybe swap with another mains lead if you don't have a continuity meter).

A missing earth can be quite shocking :eek:
 
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tritty10

Standard Member
Wow, I fixed it! I have my TV mounted on a TV stand made for flat panel TV's that happens to be all metal. I took the TV off the stand this morning and the buzzing was gone, even with the TV turned on. So, I knew the TV's buzzing was being transferred to the speakers somehow through the metal stand, so I'm assuming the metal stand was acting like a giant antenna for the interference or something. So I lined the brackets that connect to the TV with a strip of a cotton towel (an insulator), reconnected the brackets and put the TV back up on the stand and voila, the buzzing was gone!! Wow that's such a relief, and all it cost me was a cotton towel.

Thanks to all that tried to help!
 

xmb

Well-known Member
Well done on locating the source of your interference.

But it could be still worth checking all the earths as it is unusual for a TV to be radiating so much interference.
 

Mark.Yudkin

Distinguished Member
Weird, but solved. Congratulations.
 

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