Ploki

It's not really a big deal, i'm just curious whether my math is flawed or max' math is flawed

mtof-cents-detuning-math-flawed

The example below shows the correct math, I think (assuming the U.S. standard of 440 Hz for A). There are very slight differences between the output of mtof and expr, but I'm guessing that that just has something to do with different implementations of the power function or something. The differences are pretty minuscule and should not be a problem in most cases (you have to stretch the flonum objects to be bigger in order to see the differences, which are on the order of a few 1/10,000ths of a Hz).

the mtof obejcts are using the "other" method, which is less accurate but faster.

If you take the trouble to look at mtof.maxhelp, you will see the formula that mtof actually uses.

The two [expr]s are mathematically equivalent 

. Chris' formula is more accurate because the exponent of the pow() function is always calculated to full 64-bit precision. The formula used by mtof is more efficient because the constant portion of the function is precalculated. A classic efficiency vs. accuracy trade-off.

So, show of hands, please: who can hear the difference of frequency?

The two [expr]s are mathematically equivalent to within the accuracy of 6 digits. Chris' formula is more accurate because the exponent of the pow() function is always calculated to full 64-bit precision. The formula used by mtof is more efficient because the constant portion of the function is precalculated. A classic efficiency vs. accuracy trade-off.

So, show of hands, please: who can hear the difference of frequency?


"If you take the trouble to look at mtof.maxhelp, you will see the formula that mtof actually uses."

That's not actually true anymore. The max6 help file no longer contains the expr solution.

"So, show of hands, please: who can hear the difference of frequency?"

peter: you can hear it when you mix the two methods in your patch, so it is good

to know about this difference, then decide which one to use.

peter: you can hear it when you mix the two methods in your patch, so it is good
to know about this difference, then decide which one to use.


mtof cents detuning math flawed?