Originally Posted by audioguy
Sure, the demos make use of all of the channels, but that RARELY occurs when purchasing movies. In fact, the issue seems to be getting no better. If money is no object, then the more speakers, the merrier. And on that incredibly rare occasion, all of your speakers will get utilized. But practically, the “sweet spot” is not 24, but 7.x.6.
I could go do the math if I were so inclined but if 5% of my 3D audio movies used more than 7.x.4 I would be flabbergasted!!
That 7.x.6 may be less “sweet” once DTS:X Pro is released, and we can upmix legacy 2D audio and DTS:X content to support all channels in the DTS layout we have. But certainly the 7.x.4 to 7.x.6 or 9.x.4 space is a conventional "sweet spot" for Atmos, if utility (bang for the buck) were the sole concern. But even in that case, since some Atmos mixes seem to put the static stereo overheads in the top middle, it's debatable if you really want the .6 to be TF/TM/TR (which could be FH/TM/RH as well) or just do .4 and do a center height/VOG, where that top middle would get split between the front and rear height-level channels. Or go to a .8 setup, but that primarily makes sense in a multi-row, multi-HT theatre.
Having said that, I don’t completely agree about the rare occurence, more like “less frequently than I’d like”. Also, how would you define “used more than 7.x.4”?
If you mean “enough to notice” on my > 7.x.4 layout, for Atmos mixes I’d say maybe (???) 25% to 30% of my own content, but a lot of times I only know from input meter watching. Which may be the point, considering that any floor-level speakers beyond 7.1 are “presence speakers” and part of the mix that works on conjunction with the bed speakers and overheads.
On the other hand, if you mean beyond 7.x.4 being “used all the time” without the trick of just making bed content “bigger” by spreading out side surrounds to, say, wides at a reduced level in an Atmos mix (think parts of Red Sparrow), then maybe 10% is closer to the truth.
We can agree that the whole > 7.1.4 state of the industry is mix dependent and most of all, your enjoyment (or lack of) depends on just what you're watching.