Help : Squeaking sound from front speakers when watching tv

[cychua]

Hi,
Not sure if this is normal...
I noticed that when I'm watching non 5.1 channels tv programmes, there is soft squeaking sound coming from the 2 front speakers (particularly from the tweeter).
This only happen when I switch to 5.1 modes, such as Dolby Surround. It sounds ok when I switch to Stereo or All Channels.

There is no problem when watching 5.1 contents from the HD channels, Bluray, etc.

Have been exploring on the setup on my Onkyo receiver and the cable tv box set but there is nothing that I can set to improve the situation.

Anyone has the same problem?

Thanks

[Boomzilla]

I've not had that exact problem, but I did have a distorted center channel sound once. The AVR was at fault - it had selected the wrong type of decoding for the disc being played.

[Porscheguy]

Mice?

[flamingeye]

I've heard plasma tweeter can sound like that up close

[cychua]

Ya. It sounds a bit like mice.

Not sure if mine is plasma tweeter. But the weird thing is it only happen to non 5.1 content played in surround mode.

Any recommendation what I can do to zoom in the problem?

[KeithL]

The answer may be simply NOT to play non-surround content in surround.

When you play non-surround content in a surround mode, the way it "makes" surround sound out of your source is to separate various "pieces" of the audio based on phase and timing relationships. Of course this is all guesswork, but sometimes it works pretty well. Unfortunately, certain types of anomalies (distortions) can result in just this sort of "sonic signature".

What this means is that, when the decoder starts "picking apart" your stereo content to make fake surround content, it is not unusual for occasional bits of distortion to get picked out and "stuck" in odd places... where they may get boosted and exaggerated to the point where they become noticeable and annoying. In the case of fronts, the decoder is going to assume that anything it sees in both front side speakers probably "belongs" in the center. This could well result in some slight distortion, unnoticed in the front sides, being boosted and put in the front center - where it stands out because there's nothing much else to mask it. (This could be distortion in the original content, or the results of flaws in the surround decoding.) This sort of thing was common back in the days of "four channel" - where, even though the decoding was purely analog, it used similar methods to "generate" surround from stereo.

If it happens on EVERYTHING, then you probably have a problem; but, if it only happens on certain shows or music, then you're probably just hearing what's there - and the solution is to pick a different surround mode - or just listen in stereo.

Aug 25, 2013 19:25:50 GMT -5 flamingeye said:

I've heard plasma tweeter can sound like that up close

[Jim]

Aug 26, 2013 8:55:41 GMT -5 KeithL said:

The answer may be simply NOT to play non-surround content in surround.

When you play non-surround content in a surround mode, the way it "makes" surround sound out of your source is to separate various "pieces" of the audio based on phase and timing relationships. Of course this is all guesswork, but sometimes it works pretty well. Unfortunately, certain types of anomalies (distortions) can result in just this sort of "sonic signature".

What this means is that, when the decoder starts "picking apart" your stereo content to make fake surround content, it is not unusual for occasional bits of distortion to get picked out and "stuck" in odd places... where they may get boosted and exaggerated to the point where they become noticeable and annoying. In the case of fronts, the decoder is going to assume that anything it sees in both front side speakers probably "belongs" in the center. This could well result in some slight distortion, unnoticed in the front sides, being boosted and put in the front center - where it stands out because there's nothing much else to mask it. (This could be distortion in the original content, or the results of flaws in the surround decoding.) This sort of thing was common back in the days of "four channel" - where, even though the decoding was purely analog, it used similar methods to "generate" surround from stereo.

If it happens on EVERYTHING, then you probably have a problem; but, if it only happens on certain shows or music, then you're probably just hearing what's there - and the solution is to pick a different surround mode - or just listen in stereo.

Aug 25, 2013 19:25:50 GMT -5 flamingeye said:

I've heard plasma tweeter can sound like that up close

I've heard this exact problem before. It's peculiar.

I've even been able to make it go away by changing to some other surround mode (You know, becuase non-Emotiva AVRs have tons of different faux-surround modes and goofiness)

In my experience, playing non-surround content in a surround mode is really unpredictable.