# Noise in 5.1 Surround Sound System



## abond82 (Feb 9, 2009)

I installed a 5.1 Surround sound system and am having an issue. The sound is wonderful but occasionally ususally when changing channels or when system is turned on I get a high pitched chirp sound out of either the right rear speaker or the powered sub. Any thoughts on what could be causing this sound? It is very interesting and only lasts a second....

Thx


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## BuzzKill (Oct 27, 2008)

check your grounds, isolate the stereo as much as possible from other circuits, dedicate your ground for the stereo and/or the entire circuit...just a start, this is a science unto itself.


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## abond82 (Feb 9, 2009)

This is a brand new home in a upstairs media room, the circuit for room is dedicated and has a good ground.

It always comes from the same spot, the sub or right left. Could it be something in the Rg6 line to sub? I have no clue never seen this before, just getting in the audio game.


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## BuzzKill (Oct 27, 2008)

abond82 said:


> This is a brand new home in a upstairs media room, the circuit for room is dedicated and has a good ground.
> 
> It always comes from the same spot, the sub or right left. Could it be something in the Rg6 line to sub? I have no clue never seen this before, just getting in the audio game.


 If nothing else on the circuit, I would guess internal/cord issue. Check terminations in panel.


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## BuzzKill (Oct 27, 2008)

abond82 said:


> This is a brand new home in a upstairs media room, the circuit for room is dedicated and has a good ground.
> 
> It always comes from the same spot, the sub or right left. Could it be something in the Rg6 line to sub? I have no clue never seen this before, just getting in the audio game.


 Research filters for such an issue?


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## abond82 (Feb 9, 2009)

Just happened again! So annoying.

It was when it switched to a commercial (from Dolby Digital to standard stereo) I thing it is through the subwoofer...?????


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## jamesclerie (Jun 2, 2009)

What is the source?


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## Sawdust454 (Sep 26, 2008)

What receiver are you using? Does not sound like a grounding or wiring problem, it is the receiver or the signal source, cable or satellite box.


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## EE1 (Nov 17, 2009)

You have to try this so I know if it works or not...... We are wiring a 11,000sqft house and there is a LV contractor doing the theatre wiring and sound. His biggest request from us is that the flat screen TV and the AMP needed to be on the same phase or the speaker would get feedback. Not the same circuit just the same phase. I guess its worth a shot.

Just reading your post again and in sounds like you only have one circuit though already......


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## Speedskater (Oct 2, 2009)

EE1 said:


> You have to try this so I know if it works or not...... We are wiring a 11,000sqft house and there is a LV contractor doing the theatre wiring and sound. His biggest request from us is that the flat screen TV and the AMP needed to be on the same phase or the speaker would get feedback. Not the same circuit just the same phase. I guess its worth a shot.
> 
> Just reading your post again and in sounds like you only have one circuit though already......


He may or may not have problems, but speaker feedback won't be one of them.

The original problem sounds like interference or an internal (to the equipment) problem.


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## Speedskater (Oct 2, 2009)

EE1 said:


> You have to try this so I know if it works or not...... We are wiring a 11,000sqft house and there is a LV contractor doing the theatre wiring and sound. His biggest request from us is that the flat screen TV and the AMP needed to be on the same phase or the speaker would get feedback. Not the same circuit just the same phase. I guess its worth a shot.
> 
> Just reading your post again and in sounds like you only have one circuit though already......


If I were wiring a theater like that. I would run an extra heavy line from the main to a 6 breaker box located near the A/V equipment rack.


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## jamesclerie (Jun 2, 2009)

Most likely the problem is the digital switching form the source. The program is in dolby digital and the commercials are in standard stereo.Every time the sound field changes there is a noise for the switching. My suggestion is to lock the A/V receiver in Dolby Digital do not use the auto signal option.


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## abond82 (Feb 9, 2009)

thx for the info. The source is a yamaha reciever from a dish network sat. box. The issue usaully is when turning on and when switching from DD to stereo. 

How do you lock the receiver in DD????


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## jamesclerie (Jun 2, 2009)

Use the audio field select option until it is set on ProLogic


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## abond82 (Feb 9, 2009)

I am set on prologic... and i just noticed it happen again randomly during normal DD operation. I am pretty sure it is in the sub or right rear surround speaker. Any other ideas????


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## msdmsd (Nov 27, 2009)

abond82 said:


> I am set on prologic... and i just noticed it happen again randomly during normal DD operation. I am pretty sure it is in the sub or right rear surround speaker. Any other ideas????


Is it only while listening to the cable/sat box as a source?

Your sub shouldn't be able to produce a high pitched sound.


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## abond82 (Feb 9, 2009)

I have only noticed during sat box operation. Im not sure if it is sub or surround speaker just thought it was odd tthat it is only one speaker....


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## msdmsd (Nov 27, 2009)

How is it physically connected to the receiver? I'm assuming digital coax or optical...or you wouldn't be getting the digital signal. If you have both options switch it to the other.

It's not that odd if it's only coming from one speaker...it's just the way your receiver is decoding the digital signal from the sat box.

I'm going to assume it's your sat box and would try a hard reset or even getting a new box if it is leased from the sat. company.

Or switching it with another box in the house that isn't connected to a receiver.


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## modified electric (Oct 29, 2009)

disconnect the speakers one at a time to try to isolate the problem speaker if it not that it could be an equ. problem


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## sparkysteve (Jan 23, 2007)

Try putting a ground loop isolator in the coax line feeding the TV. They are also sometimes called isolation transformers. I had the same problem because I hooked my computer to my home theater system. It made a humming noise with my cable box hooked up until I added one. They also make them for RCA jacks. Radio Shack should be able to hook you up.


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