(Warning: long rambling post ahead)
Most games _do_ use real recorded samples, but they have to pitch-shift them
to simulate different rpms (although you can sample at different rpms and
cross-fade between them). So if you're at constant RPMs near the point
where the sample was taken, it'll sound the same as the recording.
Sometimes you can get lucky and get a really good sample that sounds good at
different pitches, but that's a real art. Even if you sample a lot of rev
ranges, it's hard to mix between them without hearing weird interference
artifacts, or else a discontinuity if you don't mix. Also trying to get
"loopable" samples is a little tricky. If there was some sort of custom
chassis dyno built for recording samples at fixed RPMs and load, that would
help, especially if it had a motor to get "engine braking" sounds.
Because of all these tradeoffs, there is a lot of disagreement about which
"sim sounds" sound good. Also, pitch shifting engine samples really isn't
right, especially at low rpms, because at some level you should be hearing
something like:
boom... boom, boom boom, boom boom boom, boom-boom-boom, b-b-b-b- ...
as the engine accelerates, all at the same pitch. The synthesis approach
actually does get those behaviors, and is better at making a more "dynamic"
engine sound that reacts to more parameters, but so far they tend to sound
somewhat artificial, especially at fixed rpms.
So basically they all suck right now in some way or another, but some can
sound really good in some conditions (such as the GPL ferrari at high RPMs,
WOT)
IMVHO, the only way to get a really good engine sound will be from a
complete accoustic simulation of an engine + exhaust system. You should try
downloading the SoundMAX/Staccatto demo to see the current "state of the
art" in synthesis. It's not "there" yet, but it is promising.
So yes, engine sounds suck right now, but it's not for lack of trying.
-Dave P.
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