Hi

Thanks for the fast response to my previous question, now here's another, I've also looked this up and not had much luck even though it seems like a fairly obvious thing to do.

I'm wanting to use a MIDI input (0-127) to control a filter's cutoff frequency (and potentially other things like volume that our ears respond to in a logarithmic manner), and I'd like that control to be effected logarithmically as it is on most synthesisers etc. It's a bit hard to get my head around the process by which this would be done so I'm not really sure how to implement it.

Also is there an equivalent to Max's [zmap] object which is very useful in such situations where scaling a number is involved?

[mtof] / [mtof~] converts midi note number to frequency in Hz

[dbtorms] / [dbtorms~] convert decibels (100 = full scale) to linear scaling values

Thanks for the help - I didn't think of using [mtof] as I wasn't using explicit note inputs, but it turns out it's fine for the purpose of scaling 0-127 values logarithmically

Hello,
I encounter a similiar problem, but my bad math cannot think of a solution itself:
I want to scale an OSC input (0.1 -1) to 1-50000 in a logarithmic manner.
I am really getting headaches over this so i would really appreciate any help.

wrong:
do you mean
expr pow(50000,($f1-.1)/.9)
?

Appreciate your quick help slur.
Well not quite. I have an inlet with floating point input ranging from 0.1 to 1.
My aim is to scale this input to an output of 1 to 50000; and i would like to do this in an logarithmic manner, and not just simple multiplying.

if you mean the way the sliders in pd behave try maxlib/scale
if you want a vanilla version try the scale from diy2
i attached it
if you need the complete opposite.. well..... i'm not bored enough now

http://www.pdpatchrepo.info/hurleur/diy2-scale.pd

Ah yes i want to imitate the way sliders work when set to "log" mode.

I had my problems understanding the vanilla version, but the maxlib scale object works perfectly, thank you very much for your help.

Regards, Sven