Weird "running water" noises from Pro Logic surround amp...

On certain settings, from certain inputs on my Sony STR-DE495 i'm getting a kinda "running water" noise from my rear speakers when using any of the Dolby Pro-Logic/Pro Logic II movie or music sound settings.

At the moment, i only have one input into my receiver and it happens on this input. It does not happen on the internal FM tuner though.

Someone else informed me that it was something to do with Pro Logic, but he didn't explain it very well at all.

Can someone shed any light on this?

My only workaround at the moment is to either use 2-channel stereo, or to use one of the special Music settings for either Concert, Hall or Jazz. I don't seem to have an option for just playing my music out of all the speakers...

A pic of my receiver can be found here to save researching it: http://hififorum.co.uk/modules/myalb...p?lid=16&cid=1

Thanks in advance to anyone who can help with this.

Quote:

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Originally Posted by fishsponge

On certain settings, from certain inputs on my Sony STR-DE495 i'm getting a kinda "running water" noise from my rear speakers when using any of the Dolby Pro-Logic/Pro Logic II movie or music sound settings.

At the moment, i only have one input into my receiver and it happens on this input. It does not happen on the internal FM tuner though.

Someone else informed me that it was something to do with Pro Logic, but he didn't explain it very well at all.

Can someone shed any light on this?

My only workaround at the moment is to either use 2-channel stereo, or to use one of the special Music settings for either Concert, Hall or Jazz. I don't seem to have an option for just playing my music out of all the speakers...

A pic of my receiver can be found here to save researching it: http://hififorum.co.uk/modules/myalb...p?lid=16&cid=1

Thanks in advance to anyone who can help with this.

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Pro Logic is NOT a good choice for listening to music. It was designed specifically for movie soundtracks. In order you you to decode them properly you must use a digital input, either coax, or toslink.

Stereo, Concert, Hall or Jazz appear to be your only choices for music, as your receiver does not seem to have the newer DTS NEO 6.

Pro Logic II [which his unit has] is good for listening to music, and was designed to convert music as well as movie sound tracks from2 channnel to multi-channel. It is an improvement over DPL. It's a preference issue as to whether DPLII or DTS Neo 6 is better. Sorry I can't help resolve the "running water" problem. Good luck with problem fishsponge.

the soud of running water electronically on a regular basis is reverb. I'm not familar with the Sony per se, but the sound effect you're describing does sound a lot like reverb.

Just my 2 cents..

Da Worfster :o

Quote:

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Originally Posted by TinHere

Pro Logic II [which his unit has] is good for listening to music, and was designed to convert music as well as movie sound tracks from2 channnel to multi-channel. It is an improvement over DPL. It's a preference issue as to whether DPLII or DTS Neo 6 is better. Sorry I can't help resolve the "running water" problem. Good luck with problem fishsponge.

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I stand corrected. I just listened to music with the receiver set to pro-logic and it does play. Just for kicks I pulled the wires on the mains, and the darn surrounds sounds like the're underwater! Then I set it to the Dolby music mode and it was much better. Heck, even the Dolby movie mode was better. This is also confirmed by a quick look at the file;

http://www.dolby.com/tech/l.wh.0007.PLIIops.pdf

It seems that Dolby prologic II uses a 7kh filter for surround just like the original Pro logic, an auto balance circuit, and a non user adjustable delay. The music selection on the Dolby Prologic II is much better for music, with no default delay setting, although it still uses a mild HF filter.

I think the confusion here is that he's using the Pro Logic II mode, when he should be using the Pro Logic II music mode. The music modes are still a Pro Logic II setting, but by choosing one of the music modes he's telling the decoder to decode it as music, as opposed to a Dolby surround encoded track.

For my tastes in music I much prefer stereo, or the DTS NEO 6 speaker stereo setting if I don't feel like powering up the maggies. I guess that's why these receivers go so many modes!

As for the running water sound...

Could this perhaps be, for some crazy reason, the test mode for those speakers running? I know on my NAD receiver, I have a button on my remote labled "Test" and if pressed while in one of the surround modes, it will send a "running water" sound to each of the speakers, moving from first the left main, to center, to right main, to right surround, to left surround, and back to left main. It's basically a "noise" allowing for volume adjustment of the individual channels so that they can all be matched up. Maybe...for some reason...that's what's happening? I dunno...

I have the exact same issue with my HT set up (Sony HTIB DDW-750P) and the "gurgling water sound" would have been exactly the way I will describe it.

But this sound level is so low that I have to be sitting right next to the speaker to notice it and I kinda never bothered thinking that it must be some thing to do with PL/PLII approximation algo (after all its approximation only, right?)

It happens more in some music CD's, less in others, and its not the test tone for sure....