On Fri, 14 Mar 2008 15:43:59 +0100, Asgeir Nesoen wrote:

> Well, I disagree on a number of points, but I'll start with a field of
> which I know a lot, namely recognizing minute changes in pitch.
>
> I play several instruments, and I'd say I would be able to "hear", or
> "regocnize" a change of a 20th of a seminote, or 10 times more sensitive
> than you presume. If you're trained (piano tuners, organ tuners) or with
> "perfect pitch" sense, you'll be able to recognize maybe a change of a
> 50th of a seminote.
>
> You would, in a race care hear the "rate of change" in pitch more than
> "aboslute pitch", and a normally musical ear will draw massive info from
> a changing engine "tone". You would not translate pitch to speed, but
> you'd translate rate of change to speed.
>
> It is difficult to describe engine noise as frequency, since you hear
> overtones of the base frequency. An engine with 12000 revs/min equals a
> base frequency of 200hz, 20 hz lower than the "little a" of 220 hz. This
> area is by far the most sensitive area of an ear, and we would have the
> most resolution in this area. Our ears are most sensitive in the
> "speech" frequencies.
Oops, now I see a fatal flaw in my argument. Of course, being
scientifically minded I've optimistically assumed that the engine revving
at 18000 makes 18000 rotations per second = 18 kHz, but simple reality
check confirms that automotive technology is still in the stone age I
agree with your estimate of ear sensitivity at 200Hz range. In fact, it's
probably even easier to tell the difference because of 2x and 4x waves.
That's very unlike 18kHz range where overtones are out of the range.

>
> If you make these assumptions, you'd come up with a hugely effective
> instrument for speed reading. If you don't go faster with sound than
> without, you need to practice your ear. One way to do this is to stick a
> piece of carton over your in-car rev meter, so that the only input in
> the speed dept would be the sound, and you would HAVE to use your ear.
>
> With practice you will be able to judge your speed accurately to 1 or 2
> km/h, and this would be a perfect tool for racing. You would not be able
> to say "I'm now running down the straight at 301km/h", but you would be
> able to say "I'm now running at 3kmh slower than my target speed at this
> point". Again, not an absolute reading of speed, but a very good
> relative reading of your speed.
>
> And you're right: Grip is changing all the time, and this is where a
> real car would give you heaps of info, but the sim gives you very
> little.
Yes and no. In the sims you usually have a lot of information about the
grip if you've already run through that spot before (or typically just
run on the same surface), but in the real car you have to guess amount of
traction purely from the visuals. Of course, you get much more info when
you actually get there, but by that time it may be too late. That
probably makes most people to leave much healthier margin of error when
driving the real car.

> This is probably why it is hard to push very hard on a sim car,
> because you only get sound from tires, and no G-pull, no vibration. In
> real life you would also get much more info from the tyre screech than
> in a sim, since the sound will accurately describe what happens with a
> tyre.
I wonder if you can hear tyre screech in something like F1 car. That
engine must be making a lot of noise...