Forums > MaxMSP

not understanding max's log computation

September 16, 2009 | 2:23 am

Hi,

I’m trying to use [scale] to output logarithmically, but can’t really understand how it is calculating its output. If the exponential base value is very close to 1 (e.g. 1.005) the first number output is much higher than 0.

Maybe it’s a lack of understanding of maths on my part, but it seems to me as though the curve should still be starting at 0, even if it looked almost exactly like a straight line, then as the exponent gets higher the curve would develop and show itself more drastically.

So… why the big jump at 0? And what can I do to get a good scalable logarithmic curve?

Jay

– Pasted Max Patch, click to expand. –

September 16, 2009 | 6:36 am

There’s a common understanding among max users that scale is not suitable for logarithmic scaling. It doesn’t work. (As long as you ignore it’s fifth argument, it’s a fantastic object.) One of the ways of dealing with this is:

– Pasted Max Patch, click to expand. –

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johan


September 16, 2009 | 8:25 pm

Also, check out the awesome (and free!) Litter Power Starter Pack:

http://www.bek.no/~pcastine/Litter/

The lp.scampf object has log/expo scaling which works perfectly!


September 16, 2009 | 11:34 pm

thanks for these suggestions…

i guess i should say is that i’m trying to program dials which can be logarithmically controlled, to a user-defined degree (where 1 = linear). any suggestion?


September 17, 2009 | 7:49 am

The example I posted before is exactly about this. The number 1 creates a straight line (that is a number very close to 1 like 1.000001). As this number grows, the curvature increases.

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johan


September 17, 2009 | 12:27 pm

thanks, yeah after messing around with it for a while i figured that out!


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