Set-Up is 7.1, Film is in 6.1, so what am I listening to?

[quarry2006]

I recently set up a Sony STRDH820, configured to 3/4.1 to reflect my speaker system. However, I don't own any films in 7.1. The Star Wars Blu-rays were lauded for their 6.1 mix when they came out so I was interested to hear how they sounded with this set-up.

When I play them, though, the sound comes out through all of the speakers. Now, I don't especially mind this as at least nothing is sitting dormant, and I have the two rear speakers set up so they're either side of the "sweet spot". But, I'm not entirely sure what it is that I'm listening to! Both rears are outputting the same sound as the surround speakers (they do this when I'm playing on the Xbox, too, where the sound is 5.1) so am I even hearing the film in 6.1 or just a beefier version of 5.1?

I've asked this question elsewhere, on the Movies thread, but I wasn't really satisfied with the answer (which was that the rears should be outputting the same sound, which they clearly aren't). Can anyone who has a 7.1 set-up shed some light on this, or better still someone with a STRDH820.

Many, many thanks.

 

[PSM1]

The chances are you are the rear speakers are playing the same soundtrack (the 6 part of the track spread over the 2 speakers) with the side rears playing their dedicated soundtrack which will be different to rears. So you will be listening to a psuedo 7.1 but a better 7.1 than when you listen to a 5.1 soundtrack.

 

[quarry2006]

Thanks, PSM1.

 

[dante01]

In a 6.1-channel speaker layout, surround back left and right channel sound signals are mixed down and output from the a single surround back speaker. In the 5.1-channel speaker layout, surround back left and right channel sound signals are output from the surround left and right speakers. Likewise, if a 6.1 source is being output to a 7.1 setup, both surround backs are utilised to output the one surround back channel.

Any amp detecting discrete channels not catered for by attached speakers, mixes said channels down into channels for which an attached speaker or speakers are present. The channels are not discarded, but are reproduced via the nearest adjacent speaker or speakers present.


Note that some issues are being reported in relation to some amps and the Star Wars 6.1 audio. Lucas films deny responsibility and some AV manufacturers have accept that their products are to blame. If you are having issues with this particular title then it could be due to the aforementioned hardware/decoding fault?

 

[quarry2006]

It's not so much that I'm having issues, more that I wanted confirmation on what it was that I was hearing. The manual for the receiver doesn't cover this issue, which is a shame, really.