[PD] Does Pd have a "sound"?
Claude Heiland-Allen
claude at mathr.co.uk
Mon Feb 15 15:57:36 CET 2016
On 14/02/16 22:27, Matti Viljamaa wrote:
> Do you think Pd has a characteristic sound to it? Or whether
> discussion board threads claiming Pd (and Max) have a distinct (and
> not good) sound just have people who haven’t listened to good
> patches?
Some issues with Pd that affect sound character:
1. cos~ (and osc~) use a small table with linear interpolation, which
means there is quite a lot of interpolation noise - I wrote about it
here: http://mathr.co.uk/blog/2015-04-21_approximating_cosine.html
2. vcf~ (and probably other recursive filters) use single precision
floating point in the feedback loop (pd-double might be different) which
causes weird rounding artifacts - I wrote about it here:
http://lists.puredata.info/pipermail/pd-list/2010-08/082104.html
3. cubic interpolation (tabread4~ etc) in Pd uses an (imho) incorrect
algorithm - it makes a curve that goes through 4 points instead of
matching the derivatives at the nearest 2 points, which leads to sharp
corners at the original sample points with associated aliasing artifacts
- this has been discussed on the lists many times in the past, for
example here:
http://lists.puredata.info/pipermail/pd-list/2008-06/062864.html and:
http://lists.puredata.info/pipermail/pd-list/2010-03/077278.html
4. sig~ (and implicit sig~ from float messages to signal inlets) is
steppy and only takes effect at block boundaries - compare with .kr in
SC3 which is (afaik) linearly interpolated between each block boundary
5. Pd doesn't print enough digits to perfectly reconstruct floating
point values when round-tripping through files, so (eg) biquad~
coefficients can become imprecise if you don't write them outside Pd in
a text editor
6. other systems tend to come bundled with more nice-sounding stuff like
bandlimited oscillators etc, with Pd you tend to have to find externals
yourself (deken should make that easier now)
Claude
--
http://mathr.co.uk
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