Panning with expr [was: Re: [PD] delay effects in PD: suggestions?]

Hans-Christoph Steiner hans at eds.org
Sun Nov 12 18:05:53 CET 2006


On Nov 12, 2006, at 7:27 AM, Frank Barknecht wrote:

> Hallo,
> derek holzer hat gesagt: // derek holzer wrote:
>
>> derek holzer wrote:
>>
>>> Help me out here, cause I've been using that particular dirty-but- 
>>> quick
>>> panner construction for years now. What is the difference between  
>>> your
>>> version and mine? Seems like they both give a range from 0-1 to  
>>> the left
>>> channel and the inverse of that to the right channel.
>>
>> Never mind!!!!! I figured it out. There's one patch cable in the  
>> wrong
>> place in my version. If that were fixed, our maths would be the same.
>
> Yes, it's the same. My version might be slightly faster because it
> avoids a multiplication, but then it has a variable replacement in a
> message box, which also is a bit costly. Normally I use something like
>
>   [expr 1-$f1; $f1]
>
> to do the splitting in one object but I once heard that you don't like
> [expr]. (Just joking ;)
>
> Using [expr] for panning has the advantage to allow for writing
> alternative pannings in a very compact way like:
>
>   [expr sqrt(1-$f1); sqrt($f1)]
>
>   [expr cos(1.57 * $f1); sin(1.57 * $f1)]
>
> Attached patch shows them all.

I put these three panning algorithms into objects in the "pan"  
library, and added another odd one devised by a guy named gogins, and  
included a GOP panner.

They are in the "pan" library in Pd-extended, or in CVS:

http://pure-data.cvs.sourceforge.net/pure-data/externals/hcs/pan/

.hc

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