[PD] WG: Inverse bandpass filter

Robert Esler robert at urbanstew.org
Tue Apr 22 19:37:25 CEST 2014

I could be wrong, but I don't think it's quite the same thing.  I believe
the signal would be out of phase negating many of the effects of the filter.
I would recommend using [biquad~] and in pd-extended there is a [notch]
object which takes care of the coefficients.  This sounds much cleaner and
more notch-like to my ear than subtracting the filtered output.
 There is an explanation in Miller's book if you like unit circle math:
Message: 4
Date: Tue, 22 Apr 2014 01:59:07 -0300
From: Alexandre Torres Porres <porres at gmail.com>
Subject: Re: [PD] WG: Inverse bandpass filter
To: Ingo <ingo at miamiwave.com>
Cc: pd-list <pd-list at iem.at>
<CAEAsFmhD0HanLmv9vutcSQZjkZY69i7wMeBqQ+20S2riWYaakw at mail.gmail.com>
Content-Type: text/plain; charset="utf-8"

isn't it just subtract the audio from the filtered output?

I guess you can get inverse freq response just by that


2014-04-18 17:21 GMT-03:00 Ingo <ingo at miamiwave.com>:

> You could send the original signal in parallel and invert the phase by
> multiplying with -1. You might have to delay the original signal in case
> that the processed signal gets also delayed by one or more blocks.
> Ingo
> _______________________________________
>> > Von: pd-list-bounces at iem.at [mailto:pd-list-bounces at iem.at] Im Auftrag
> von
>> > AP Vague
>> > Gesendet: Freitag, 18. April 2014 18:49
>> > An: pd-list at iem.at
>> > Betreff: [PD] Inverse bandpass filter
>> >
>> > Is there a simple way to make [bp~] or [vcf~] have an inverse function?
> To
>> > filter out, rather than pass a changing frequency value. Is the easiest
>> > way to do this with a combination of [lop~] and [hip~]?
> _______________________________________________
> Pd-list at iem.at mailing list
> UNSUBSCRIBE and account-management ->
> http://lists.puredata.info/listinfo/pd-list

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.puredata.info/pipermail/pd-list/attachments/20140422/30791f66/attachment.htm>

More information about the Pd-list mailing list