[PD] [PD-announce] new GUI obect: filterview, for generating and seeing biquad coefficients

Hans-Christoph Steiner hans at at.or.at
Sun Apr 8 18:50:05 CEST 2012


Ok, big update, this should work a lot better.

http://puredata.info/downloads/filterview

I changed the formula below to be a fixed resolution of 5 pixels.  I was thinking that this should be generalized into a general biquad~ library, so with objects like [bandpass] to calculate biquad coefficients.  The calculations could all be written in C as a shared library, then the Tcl code could use those C functions also, which I think would allow for 1 pixel resolution.  My guess is that doing the math in C would make things noticeably faster.

.hc


On Apr 4, 2012, at 3:47 PM, Mike Moser-Booth wrote:
> 
> That actually can be fixed (or at least improved) in line 75:
> 
> for {set x [expr int($framex1)]} {$x <= $framex2} {incr x [expr
> $framewidth/40]} {
> 
> It's only calculating 40 points within however many pixels the width
> is. It should probably be incrementing by a constant, with 1 being
> every pixel.
> 
> .mmb
> 
> 
> On Wed, Apr 4, 2012 at 10:06 AM, Hans-Christoph Steiner <hans at at.or.at> wrote:
>> 
>> Yeah, I've seen that.  That's really a matter of getting the math right for
>> the calculations to draw the lines.  I suck at math so I'll leave that up to
>> someone who doesn't.  The math is all in the filterview.tcl file.
>> 
>> .hc
>> 
>> On Apr 4, 2012, at 9:21 AM, batinste wrote:
>> 
>> I built it for pd-ext 64bits on ubuntu current, it works well (some crashes
>> at exit, as you said) !
>> Is there an easy way to make the magnitude response polygon less "polygoney"
>> ? If you move a strong notch filter along the spectrum, you can actually see
>> the line acting like a bike chain, thus changing the visually perceived
>> response of the filter.
>> 
>> On 03/04/2012 21:31, Marco Donnarumma wrote:
>> 
>> Looks lovely!
>> Thanks guys,
>> 
>> M
>> 
>> On Tue, Apr 3, 2012 at 8:03 PM, Hans-Christoph Steiner <hans at at.or.at>
>> wrote:
>>> 
>>> 
>>> Announcing [filterview], a new GUI object for generating and visualizing
>>> biquad coefficients.  It allows to you manipulate the filter band,
>>> frequency, and gain using your mouse.  The magnatude and phase are then
>>> graphed in realtime as the parameters changed, and the list of biquad
>>> coefficients are output. It is inspired by the [filtergraph~] object in
>>> Max/MSP.  Thanks to Mike Moser-Booth for doing all of the math behind the
>>> scenes.
>>> 
>>> It requires Pd-extended 0.43 to run. I just got to a beta state, it works
>>> well for me, but it does crash Pd sometimes when you close a patch with
>>> [filterview] in it.  Try it out and let me know how it works for you.
>>> 
>>> http://puredata.info/downloads/filterview
>>> 
>>> Also, as a side note, this object is an experiment with a new way of
>>> writing GUI objects.  It started out as a pure Tcl program, and the GUI part
>>> still runs as a standalone Tcl program (try running ./filterview.tcl from
>>> the Terminal).  This makes development and debugging vastly easier.
>>>  Additionally, I tried to move more of the GUI code to the Tcl side, so
>>> you'll see that it uses fewer widgetbehaviors, and uses Tk's bind feature
>>> quite a bit.
>>> 
>>> .hc
>>> 
>>> 
>>> 
>>> 
>>> 
>>> 
>>> 
>>> 
>>> ----------------------------------------------------------------------------
>>> 
>>>                            kill your television
>>> 
>>> 
>>> 
>>> _______________________________________________
>>> Pd-announce mailing list
>>> Pd-announce at iem.at
>>> http://lists.puredata.info/listinfo/pd-announce
>>> 
>> 
>> 
>> 
>> --
>> Marco Donnarumma
>> New Media + Sonic Arts Practitioner, Performer, Teacher, Director.
>> ACE, Sound Design MSc by Research (ongoing)
>> The University of Edinburgh, UK
>> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>> Portfolio: http://marcodonnarumma.com
>> Research: http://res.marcodonnarumma.com | http://www.thesaddj.com | http://www.flxer.net
>> Director: http://www.liveperformersmeeting.net
>> 
>> 
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>> 
>> ----------------------------------------------------------------------------
>> 
>> If you are not part of the solution, you are part of the problem.
>> 
>> 
>> 
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> 
> 
> 
> -- 
> Mike Moser-Booth - mmoserbooth at gmail.com
> Master's Student in Music Technology
> Schulich School of Music, McGill University
> Centre for Interdisciplinary Research in Music Media and Technology
> 
> "Words that make questions may not be questions at all." -- Neil deGrasse Tyson



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