# [PD] can [bp~] be obtained with biquad coefficients?

Alexandre Torres Porres porres at gmail.com
Wed Apr 9 14:59:42 CEST 2014

```Hi, that is the way I'm pointing to. I know of those but it's a bit more
complicated than that. Those bypass fiters have zero values of -1 and 1,
while [bp~] has only pole values. So my question is if I can achieve [bp~]
by only turning the zero values of -1 and 1 to 0. I actually tried it and
it didn't seem to do the trick.

Maybe I'm doing something wrong. I don't know. It'd solve my issue if I
could have [bp~] as biquad coefficients. But if not, I'd need some
guidelines on how to plot the frequency response in the same way as
[filterview] or [mmb.filterplot] plot the biquad coefficients.

Cheers

2014-04-09 8:30 GMT-03:00 Colet Patrice <colet.patrice at free.fr>:

>  Le 09/04/2014 01:45, Alexandre Torres Porres a écrit :
>
> Hi there. I'm trying to find a way to plot the frequency response
> of [bp~].
>
>
> Hello, I don't know if it helps, in ggee there are filter objects that are
> applying formula for biquad coefficients, it's easy to use those formula in
> expr and apply them to biquad object in vanilla.
>
>  I know of patches that can plot from biquad coefficients, so it'd be
> great if I could get biquad coefficients from an input of frequency and Q.
>
>  I see [bp~] is a 2 pole filter. So does it mean I can achieve it by
> zeroing out a bandpass filter made with [biquad~]? Cause I see people make
> bandpass filters with 2poles in biquad, but the zeros are at -1 and 1. I
> tried zero values of zero, but it didn't look to good to make me believe
> that's the same as [bp~].
>
>  I know of miller's example H10.measurement.pd, and compared to it,
> didn't seem to fit.
>
>  Anyway, I wanted something that would plot [bp~] right away, not like
> the H10 example, which takes some time. But then, if we can't do it with
> biquad coefficients, I would need some guidelines to do it some other how.
>
>  Thanks
>
>  Cheers
>
>  I know about filterview and patch
>
>
> _______________________________________________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/20140409/4b5d80ac/attachment.htm>
```