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Very basic stereo versus 5:1 question?

If you are running 5:1, does the left and right front channel get adjusted for frequency compared to listening to the same soundtrack as stereo?

The reason I ask is that I my 5:1 digital inputs just died and so I switched to running stereo. The amount of bass detail that showed up in the stereo output was much improved over what I was getting in a the 5:1 setup. This is for watching TV movies and motor racing.

The 5:1 front channel L/R is through a Bryston SP 1.7, Bryston amp to B&W 801 fronts. When I switched to stereo mode I sent the same signal to a Bel Canto DAC, the same Bryston amp and the same B&W 801 fronts.

I watch motor racing and the quality and impact of the bass is much improved in stereo mode. Missing the center channel is certainly noticeable for dialog in movies etc. So, best of both worlds would be 5:1 but with the same bass quality as I get in stereo mode.

Is there some inherent difference in the signal quality of 5:1 front information versus stereo that might account for this difference?

Any thoughts suggestions?

thanks, Mark.
mkeeton
swampwalker's avatar
swampwalker
5,138 posts
 
I notice you did post a center speaker or sub. If you are using them that could explain it. The processor bass management may be sending the bass to an "imaginary" sub. In stereo mode it is being sent to the main L and R.
mkeeton OP
2 posts
 
Thanks. Those are both helpful to consider. I don't believe the processor is set for a sub. I wouldn't have set it up that way since I don't run a sub. But maybe in there I messed up. I will try that and see if that makes any difference.
swampwalker's avatar
swampwalker
5,138 posts
 
But in 5.1 the .1 is a sub. I think some processors allow for a phantom center channel.
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dbphd
1,628 posts
 
Swampwalker wrote: "But in 5.1 the .1 is a sub. I think some processors allow for a phantom center channel."

I suspect those processors also send .1 to speakers designated as large or full range if no sub is specified in the menu.

db
swampwalker's avatar
swampwalker
5,138 posts
 
"I suspect those processors also send .1 to speakers designated as large or full range if no sub is specified in the menu"

May or may not be true; I was pointing that out so the OP could check for sure. I was thinking along the same lines as Kal, that there is no reason for that to be true, unless there is some quirk in the DSP or bass management software that does not route the deep bass to the fronts in 5.1 if there is no specified. Of course since the OP never specified that he was using a sub or a center, it's also possible that in 5.1, he was NOT routing the deep bass or LFE channel to the fronts. Another possibility is that he had (mistakenly) identified the fronts as small or otherwise fooled the bass management software NOT to send the full range signal including the LFE channel, to the fronts. I will admit that Kal is WAY more knowledgeable about multichannel than I am.
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