[L2Ork-dev] filters

Gilberto Agostinho gilbertohasnofb at googlemail.com
Sat Jan 31 11:59:55 UTC 2015

Hello all,

Recently I wrote a message here and in pd's mailing list about some 
possible bugs involving the filters [hip~] and [bp~]. As it turns out, 
those were not bugs but rather limitations of the algorithms themselves 
(the discussion in pd's mailing list can be found here: 
https://www.mail-archive.com/pd-list@lists.iem.at/msg02169.html )

The filter [bp~] cannot be used for frequencies higher than 12 kHz, 
which in the end is not much of a big deal in most cases (and in those 
cases, there is always [vcf~] to solve it since it does not show this 
limitation). But the problems with [hip~] cannot be that easily ignored: 
it does not output -3 dB at the cutoff frequency as expected. But 
another high pass filter included in pd, [iemlib/hp1~], does this 
perfectly well and also has no limitation for higher frequencies.

So here is the thing: we do have this perfectly good high pass filter 
that is slightly more hidden than what most people consider to be the 
"default" HP filter (virtually all tutorials and books about Pd use 
[hip~], and I guess the majority of users are very likely to be using it 
only). So why not make [hp1~] the default filter itself? That is, 
replace [hip~] for [hp1~].

I know this is not very orthodox, it may break someone's patch if that 
patch depends on this inconsistency of the original [hip~] and when 
opening a patch in pd vanilla or extended you would be welcomed with the 
original [hip~], but in the end it would make pd-l2ork better in my 

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