5.1, 6.1, 8.2, 10.2, NOW 7.1 and 7+7.1, Which is which?

[admin_exported]

I understand that the numbers refer to the number of DISCRETE channels being produced, so I believe that the 5.1 means front and rear left and right, center front plus a single mono sub bass channel. 6.1 then adds a discrete center rear channel. SO FAR SO GOOD. However we now get to the 8.2 system. Assuming this is just adding a further 2.1 channels to the 6.1 system, where do these next 3 channels go? On my Yamaha system these extra 2 are high level mounted, front effect speakers and the extra .1 is a second sub channel. Now is this front and rear subs or left and right, I have seen both. I also have 3 sub pre-outs, mono, left and right, but most diagrams I see show front and rear. Which is it? I have also seen those extra 2 channels as mid-way between front and rear, ie side channels. So is 10.2 then front efffects AND sides, with stereo subs or front/rear subs. And where the hell do we get a 7th channel from without losing the center rear? Is there no fixed format or is it all getting a little silly?

 

[Anonymous]

7.1 is the same as 6.1, except that it uses 2 speakers for the centre rear channel, but each speaker is fed the same info, ie still only 6 discrete channels of sound.

Presumably, 7+7.1 is biamping all channels?!?!

 

[Andrew Everard]

Right now most soundtracks are a maximum of six channels and a subwoofer - with the sixth, rear, channel either carried as discrete infoirmation or matrixed into the main surround channels.

Everything else is post-processing - Yamaha has been doing this extra front surround thing for many years, companies such as Sony use DSP to create the effect of an array of speakers extending along the side walls and round in a horseshoe behind you (as is done in cinemas), and so on.

Meridian has demonstrated systems with height channels at the front before, and at a recent AES conference ran a system with speakers above and below the listeners able to create a truly three-dimensional sound.

And yes, the 7+7.1 system does allow biamping of all speakers, as in the Lyngdorf D-1 covered in news, even with separate equalisation for each of the two amps running each speaker, as far as I understand it.

 

[Anonymous]

The extra channels are to fill gaps in larger rooms where 5.1 isnt of high enough resolution. i.e. in a wide room there is a large space between the rear channels where, in the real world, sound would exist. Thus the need for 6.1. Using the same logic, in a larger room 7.1 will span a larger space at the back of a room. Using two subwoofers will enable a more omnidirectional bass pattern. A lot of this information is made up from a 5.1 or 6.1 bitstream by the receiver. Like Yamaha with their prescence speakers above the front L and R channels, as you have explained.