
Don't be silly.

Using the Sound Manager on a Quadra is very well, but using SM on
any of the low-end machines doesn't simply work for a decent action
game since it just steals too much time from the CPU. This is
a fact. By writing directly to the hardware on an SE, it is
possible to have 4 simultaneous channels of sampled sound (11kHz) for
a cost of approx. 8000 cycles. Exactly how would you do that using
the SM, pray tell?

The correct thing to do is to use the SM on the machines that can
carry that extra load using the SM means, and to write directly
to the sound hardware on the machines that can't. It's not the
politically correct thing, but from the developers' point of
view it is.
