[PD] bugs with [hip~] and [bp~]

[Gilberto Agostinho]

Hello all,

An user reported a bug in the forum about some problematic behaviours of 
certain filters in pd-extended 0.43.4, particularly [hip~] and [bp~]. I 
found this bug to be also present in pd vanilla 0.46.5. Basically, these 
filters do not respond to frequencies higher than approximately 12 kHz, 
in contrast to [vcf~] which responds to any frequency. This can be very 
clearly observed in the case of [bp~] using a narrow band frequency sweep.

Here is a video showing the problem: http://youtu.be/A7mPhiHcmhc
Here is the topic in our forum where this discussion started: 
http://forum.pdpatchrepo.info/topic/8967/highpass-hip-not-working-as-expected/18
Here is that user's bug report concerning pd-extended: 
https://sourceforge.net/p/pure-data/bugs/1187/
Finally, here is the patch I am using to test this (I am using 
[spectrogram~] (which in its turn needs [metrum] and [multiplex~], all 
of which are included in this compacted file): 
https://www.dropbox.com/s/fcwciwe8klwh5xz/filter-test.zip?dl=0

NOTE: the user that reported the bug argues that pd vanilla 0.45.4 does 
not produce any problems, but I firmly believe this to be a mistake of 
him. I tested these filters in both 0.45.4 and 0.46.5 and both produce 
the same behaviour. I tried to contact him to ask for further tests (he 
was not using my patch above for his own tests), but so far I got no 
reply. Also, other users confirmed this bug to be present in both 
vanilla and extended.

Please let me know if I can be of any help with this.

Best,
Gilberto Agostinho