5.1 -=- 7.1 (1 Viewer)

[BobHaymond]

I gather that most playback is 5.1 [is that so? ] What is the process if it is played on a 7.1 system?

 

[Michael Reuben]

Despite a lot of loose talk, there really is no such thing as "7.1". For further discussion, look at this thread.
Receivers or pre/pros that have outputs for 7 separate speakers each have their own way of processing signals for playback through that array. For example, Lexicon processors use a proprietary scheme called "Logic7" to open up the rear channels of a 5.1 source.

I gather that most playback is 5.1 [is that so? ]

Only if the source is 5.1. Many films and most music are recorded with just 2 channels. On playback, those 2 channels can be processed into more, but they're still just 2 channels.
M.