Forums > MaxMSP

scaling linear to logarithmic: using slider to control biquad filter cutoff

Apr 26 2012 | 3:41 pm

I am wanting to control the cut-off frequency of a biquad filter with a slider or dial. I have noticed that the scaling of a slider to a filter, i.e. [0 127 0.0001 22000], does not work so well as the filter is logarithmic by default. Can anyone advise me on a way around this?

Apr 26 2012 | 6:11 pm

if you can’t find the expression [linedrive] might be of help.

Apr 26 2012 | 8:01 pm

[curve] or something like that maybe?

Apr 26 2012 | 8:34 pm

I will try both of those suggestions. Someone told me that to map a 0 127 linear to 0 22000 logarithmic scale you should carry out the equation log127(2200). Does anyone know how I would go about doing this with the expression object?

Apr 07 2016 | 3:40 am

Hi, i am bumping this, because i’d like to control a filter cutoff with a dial.
Any help with the expression ? i know it’s basics of maths and audio, but….

Thanks !!

Apr 07 2016 | 3:42 am

Well, i found in a tutorial that mtof could do the trick !

Apr 07 2016 | 12:19 pm

that is about what i would suggest.

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Forums > MaxMSP