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Dolby Pro Logic - voices are just low volume chirps!?


Novice Member
I’m sure this cant be right!

- Pioneer vsx-916 amp
- Pioneer S-V410 5.1 speakers
- Freeview box – outputs component video and optical audio into the amp (although the actual transmission audio is stereo)

So here’s my problem, when watching normal tv, if I put the amp into Dolby Pro Logic mode, my rear surround speakers play up. Most of the sound comes through fine, but the voices when people are speaking on the tv come through really low volume and chirpy – almost the same sounds as a volume fax transmission but very muffled so its not so ear piercing. There’s absolutely no chance of making out whats being said, its merely just an extremely low volume chirping (but in time with the speaking on the tv).

All audio (including voices) come through fine on most of the other preset modes (i.e. the music, movie, cinema preset etc.). Also, I’ve tested Dolby Pro Logic on other sources like the DVD player (optical coax connection) and that comes through fine.

I tried disconnecting the cabling and re-cutting the cable connections but no change. I then tried adjusting settings on the amp but still nothing.
Originally I was having this problem with the front Left & Right as well but when I changed a setting called ‘dialogue’ to ON this has solved it with the fronts, but the rears are still playing up.

In addition, I’ve noticed that when I turn my amp on after leaving it off overnight I get a buzz from all speakers for about 10-15 seconds. I’m not sure if the 2 things are linked…?

I’m really cant pin point this :confused:. Any ideas anyone? :lease:


Distinguished Member
There's nothing wrong, that's just the way it is.
It's down to the way DPL splits the signal up and as you've discovered, it's not perfect. All it's doing is turning a 2 channel stereo signal into 5 channels.
That explains why DD etc are ok, it's because they are 6 totally exclusive channels, which are not being split up.
Simple solution?
Move your ears away from the rears and listen in a normal position :D

If you can hear it in your normal position, the rears are probably too loud.


Novice Member
Cheers for that, sounds re-assuring and plausible. I'd just never heard it before and assumed that it had just developed.
I did wonder also whether I was hearing digital artifact on the source video/audio perhaps...

(or indeed if I had wired my rears into the wrong place on the back of the amp ;) - its a 7.1 capable amp)

Wonder what the initial boot up buzzing is then, because that definately didnt use to be there..


Distinguished Member
I can't comment on that because I don't have a clue what it could be, especially as you said it never used to do it :confused:


Novice Member
Yeah its like a mild buzzing when the amp has been off for a while. It actually comes through the speakers as opposed to just the amp unit itself.

It happens even without any other source going through it, so basically if the amps the first thing I turn on before the tv or freeview box its still there...

Anyone any ideas? :confused:

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