[LAD] Re: Calculating logarithmic curve for controller automation

On Fri, Feb 24, 2023 at 12:14:19PM +0100, Stefano D'Angelo wrote:

> > Given any three points (x1, y1), (x2, (y1+y3)/2), (x3, y3) where
> > y1>y2>y3 or y1<y2<y3 you can find an exponential function passing
> > through them as explained here:
> > https://www.orastron.com/blog/potentiometers-parameter-mapping-part-1
> > (+ "output scaling").
> 
> Sorry, typo: I meant points (x1,y1), ((x1+x3)/2,y2), (x3,y3).

That function may include some exponential term, but

If

  F (x) = A exp (B * x)   # A pure exponential

then

  F ((x1 + x2) / 2) = sqrt (F (x1) * F (x2))

So the mid point is fixed, you can't choose it.

Ciao,

-- 
FA

_______________________________________________
Linux-audio-dev mailing list -- linux-audio-dev-cunTk1MwBs/[email protected]
To unsubscribe send an email to linux-audio-dev-leave-cunTk1MwBs/[email protected]