It used to be the case where a 9.4.4 was the largest number of channels you can get. In more recent years, we’re seeing 16.6.9 or 21.8.12 and even higher, crazier numbers. Unless you have an auditorium in your house, this is just a marketing gimmick! In the world we live in where society believes “more is more”, it’s just purely a way to attempt to stand out from the crowd. Larger cinemas (and by large, we mean commercial size) need more channels simply because they’re bigger, and so they need more speakers to get more coverage. A typical residential theatre just isn’t that big, and trying to squeeze all those channels into it ends up with a wall of speaker, with no separation between them, which is fundamentally poor audio engineering. There’s a pretty obvious reasons that even some of the world’s best processors on the market start at 16 channels – that’s because 16 channels is going to be more than enough for residential theatres.