Re: [PD] algorithms for drawing filter response curves
Awesome! I would like to be able to see the phase response, but since most of the time the user is only interested in the magnitude response, I think it should be something you can switch to with a message. .mmb On Wed, Feb 16, 2011 at 1:53 AM, Hans-Christoph Steiner h...@at.or.atwrote: Ok, I got it working in a limited way as a Pd object and I was controlling my first filter against noise! Good fun. You can still run the .tcl file as a standalone GUI for dev work. Get it from my git: https://github.com/pd-projects/filterview It would be quite nice if the phase was drawn as a thin line over the magnatude graph. What do you think? .hc On Feb 15, 2011, at 6:31 PM, Mike Moser-Booth wrote: Hey Hans, Here's an update of filterview. There are now procs for the following filters: lowpass highpass allpass bandpass resonant peaking highshelf lowshelf I've added some lines to show the phase response (you have to comment out line 135 and uncomment 136 to see it). I also adjust the bandwidth calculations so the handles sit where they should (i.e. -3dB for bandpass/notch/etc., 1/2 power for peaking/shelf). btw, the frequency axis is log-scaled, though it could probably be improved a little. I sort of took a Pd approach to it by making an mtof proc, so the x-axis gets scaled to linear midi notes and converted to log-frequencies. :-) There might be a simpler way to do it. It also doesn't go all the way down to 0 Hz, because doing that with this approach causes the lowest frequencies to take up too much of the graph. I think Max gets around it by using a more compressed scale below 1-2 Hz. .mmb On Thu, Feb 10, 2011 at 12:39 AM, Mike Moser-Booth mmoserbo...@gmail.comwrote: Sure, I can throw the others together. Now that one is done the rest should fall into place pretty easily. It might take me a couple of days to get to it, though. .mmb On Wed, Feb 9, 2011 at 11:47 PM, Hans-Christoph Steiner h...@at.or.atwrote: That's awesome, thanks! I committed it under your name: https://github.com/pd-projects/filterview I'd like to implement all of the relevant filters, which algorithms should I use? Or even better, perhaps you want to take a crack at it while I figure out how to display the x/frequency on a log scale :-D .hc -- Mike Moser-Booth mmoserbo...@gmail.com -- Mike Moser-Booth mmoserbo...@gmail.com filterview.mmb.tcl.zip Programs should be written for people to read, and only incidentally for machines to execute. - from Structure and Interpretation of Computer Programs -- Mike Moser-Booth mmoserbo...@gmail.com ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list
Re: [PD] algorithms for drawing filter response curves
On Feb 16, 2011, at 9:17 PM, Spencer Russell wrote: On Wed, Feb 16, 2011 at 1:53 AM, Hans-Christoph Steiner h...@at.or.at wrote: Ok, I got it working in a limited way as a Pd object and I was controlling my first filter against noise! Good fun. You can still run the .tcl file as a standalone GUI for dev work. Get it from my git: https://github.com/pd-projects/filterview It would be quite nice if the phase was drawn as a thin line over the magnatude graph. What do you think? .hc Hi Hans, This is a great addition to pd! I'm having a little trouble getting it to work properly, though. When I drag the filter window I get the error message 'invalid command name pdsend '. I just built it and copied the external binary into my pd path, then opened the help patch. thanks, Spencer Ah, ok, I'm working with 0.43 for now, but I'll have to make a fix for 0.43. .hc Mistrust authority - promote decentralization. - the hacker ethic ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list
Re: [PD] algorithms for drawing filter response curves
Did you see the phase line in the current implementation? I think its nice to have it there all the time, as long as its not dominant. I think having the phase line there will remind people that the effects of filters are never as simple as removing selected frequencies. .hc On Feb 17, 2011, at 12:53 PM, Mike Moser-Booth wrote: Awesome! I would like to be able to see the phase response, but since most of the time the user is only interested in the magnitude response, I think it should be something you can switch to with a message. .mmb On Wed, Feb 16, 2011 at 1:53 AM, Hans-Christoph Steiner h...@at.or.at wrote: Ok, I got it working in a limited way as a Pd object and I was controlling my first filter against noise! Good fun. You can still run the .tcl file as a standalone GUI for dev work. Get it from my git: https://github.com/pd-projects/filterview It would be quite nice if the phase was drawn as a thin line over the magnatude graph. What do you think? .hc On Feb 15, 2011, at 6:31 PM, Mike Moser-Booth wrote: Hey Hans, Here's an update of filterview. There are now procs for the following filters: lowpass highpass allpass bandpass resonant peaking highshelf lowshelf I've added some lines to show the phase response (you have to comment out line 135 and uncomment 136 to see it). I also adjust the bandwidth calculations so the handles sit where they should (i.e. -3dB for bandpass/notch/etc., 1/2 power for peaking/shelf). btw, the frequency axis is log-scaled, though it could probably be improved a little. I sort of took a Pd approach to it by making an mtof proc, so the x-axis gets scaled to linear midi notes and converted to log-frequencies. :-) There might be a simpler way to do it. It also doesn't go all the way down to 0 Hz, because doing that with this approach causes the lowest frequencies to take up too much of the graph. I think Max gets around it by using a more compressed scale below 1-2 Hz. .mmb On Thu, Feb 10, 2011 at 12:39 AM, Mike Moser-Booth mmoserbo...@gmail.com wrote: Sure, I can throw the others together. Now that one is done the rest should fall into place pretty easily. It might take me a couple of days to get to it, though. .mmb On Wed, Feb 9, 2011 at 11:47 PM, Hans-Christoph Steiner h...@at.or.at wrote: That's awesome, thanks! I committed it under your name: https://github.com/pd-projects/filterview I'd like to implement all of the relevant filters, which algorithms should I use? Or even better, perhaps you want to take a crack at it while I figure out how to display the x/frequency on a log scale :-D .hc -- Mike Moser-Booth mmoserbo...@gmail.com -- Mike Moser-Booth mmoserbo...@gmail.com filterview.mmb.tcl.zip Programs should be written for people to read, and only incidentally for machines to execute. - from Structure and Interpretation of Computer Programs -- Mike Moser-Booth mmoserbo...@gmail.com Terrorism is not an enemy. It cannot be defeated. It's a tactic. It's about as sensible to say we declare war on night attacks and expect we're going to win that war. We're not going to win the war on terrorism.- retired U.S. Army general, William Odom ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list
Re: [PD] algorithms for drawing filter response curves
Ok, I pushed updates to the git repo so it should now run using Pd older than 0.43. .hc On Feb 17, 2011, at 12:53 PM, Mike Moser-Booth wrote: Awesome! I would like to be able to see the phase response, but since most of the time the user is only interested in the magnitude response, I think it should be something you can switch to with a message. .mmb On Wed, Feb 16, 2011 at 1:53 AM, Hans-Christoph Steiner h...@at.or.at wrote: Ok, I got it working in a limited way as a Pd object and I was controlling my first filter against noise! Good fun. You can still run the .tcl file as a standalone GUI for dev work. Get it from my git: https://github.com/pd-projects/filterview It would be quite nice if the phase was drawn as a thin line over the magnatude graph. What do you think? .hc On Feb 15, 2011, at 6:31 PM, Mike Moser-Booth wrote: Hey Hans, Here's an update of filterview. There are now procs for the following filters: lowpass highpass allpass bandpass resonant peaking highshelf lowshelf I've added some lines to show the phase response (you have to comment out line 135 and uncomment 136 to see it). I also adjust the bandwidth calculations so the handles sit where they should (i.e. -3dB for bandpass/notch/etc., 1/2 power for peaking/shelf). btw, the frequency axis is log-scaled, though it could probably be improved a little. I sort of took a Pd approach to it by making an mtof proc, so the x-axis gets scaled to linear midi notes and converted to log-frequencies. :-) There might be a simpler way to do it. It also doesn't go all the way down to 0 Hz, because doing that with this approach causes the lowest frequencies to take up too much of the graph. I think Max gets around it by using a more compressed scale below 1-2 Hz. .mmb On Thu, Feb 10, 2011 at 12:39 AM, Mike Moser-Booth mmoserbo...@gmail.com wrote: Sure, I can throw the others together. Now that one is done the rest should fall into place pretty easily. It might take me a couple of days to get to it, though. .mmb On Wed, Feb 9, 2011 at 11:47 PM, Hans-Christoph Steiner h...@at.or.at wrote: That's awesome, thanks! I committed it under your name: https://github.com/pd-projects/filterview I'd like to implement all of the relevant filters, which algorithms should I use? Or even better, perhaps you want to take a crack at it while I figure out how to display the x/frequency on a log scale :-D .hc -- Mike Moser-Booth mmoserbo...@gmail.com -- Mike Moser-Booth mmoserbo...@gmail.com filterview.mmb.tcl.zip Programs should be written for people to read, and only incidentally for machines to execute. - from Structure and Interpretation of Computer Programs -- Mike Moser-Booth mmoserbo...@gmail.com A cellphone to me is just an opportunity to be irritated wherever you are. - Linus Torvalds ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list
Re: [PD] algorithms for drawing filter response curves
Very cool. Works for me, now. Strangely within the help patch my cursor is always the arrow, and doesn't change to the hand when I'm in Edit Mode, and doesn't highlight when the cursor is over inlets/outlets. -spencer On Thu, Feb 17, 2011 at 9:20 PM, Hans-Christoph Steiner h...@at.or.at wrote: Ok, I pushed updates to the git repo so it should now run using Pd older than 0.43. .hc On Feb 17, 2011, at 12:53 PM, Mike Moser-Booth wrote: Awesome! I would like to be able to see the phase response, but since most of the time the user is only interested in the magnitude response, I think it should be something you can switch to with a message. .mmb On Wed, Feb 16, 2011 at 1:53 AM, Hans-Christoph Steiner h...@at.or.at wrote: Ok, I got it working in a limited way as a Pd object and I was controlling my first filter against noise! Good fun. You can still run the .tcl file as a standalone GUI for dev work. Get it from my git: https://github.com/pd-projects/filterview It would be quite nice if the phase was drawn as a thin line over the magnatude graph. What do you think? .hc On Feb 15, 2011, at 6:31 PM, Mike Moser-Booth wrote: Hey Hans, Here's an update of filterview. There are now procs for the following filters: lowpass highpass allpass bandpass resonant peaking highshelf lowshelf I've added some lines to show the phase response (you have to comment out line 135 and uncomment 136 to see it). I also adjust the bandwidth calculations so the handles sit where they should (i.e. -3dB for bandpass/notch/etc., 1/2 power for peaking/shelf). btw, the frequency axis is log-scaled, though it could probably be improved a little. I sort of took a Pd approach to it by making an mtof proc, so the x-axis gets scaled to linear midi notes and converted to log-frequencies. :-) There might be a simpler way to do it. It also doesn't go all the way down to 0 Hz, because doing that with this approach causes the lowest frequencies to take up too much of the graph. I think Max gets around it by using a more compressed scale below 1-2 Hz. .mmb On Thu, Feb 10, 2011 at 12:39 AM, Mike Moser-Booth mmoserbo...@gmail.com wrote: Sure, I can throw the others together. Now that one is done the rest should fall into place pretty easily. It might take me a couple of days to get to it, though. .mmb On Wed, Feb 9, 2011 at 11:47 PM, Hans-Christoph Steiner h...@at.or.at wrote: That's awesome, thanks! I committed it under your name: https://github.com/pd-projects/filterview I'd like to implement all of the relevant filters, which algorithms should I use? Or even better, perhaps you want to take a crack at it while I figure out how to display the x/frequency on a log scale :-D .hc -- Mike Moser-Booth mmoserbo...@gmail.com -- Mike Moser-Booth mmoserbo...@gmail.com filterview.mmb.tcl.zip Programs should be written for people to read, and only incidentally for machines to execute. - from Structure and Interpretation of Computer Programs -- Mike Moser-Booth mmoserbo...@gmail.com A cellphone to me is just an opportunity to be irritated wherever you are. - Linus Torvalds ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list
Re: [PD] algorithms for drawing filter response curves
I think people should realize it, but the helpfile will probably remind them, too. I mean, I'm the type of person that would probably want to see it, but I don't think it's something that always needs to be seen. In general, I don't think people are particularly interested in how a lowpass filter affects the phase, and if all you're looking to do is lowpass filter a sound, it probably won't matter. Besides, the units don't line up. The y-axis goes from 25 to -25 dB in the magnitude response pi to -pi radians in the phase response. That's something that could confuse someone who doesn't really understand phase alterations to begin with. I think it makes more sense to either be able to turn it on and off or switch between the two. The more flexible the object is, the better. :-) .mmb On Thu, Feb 17, 2011 at 3:47 PM, Hans-Christoph Steiner h...@at.or.at wrote: Did you see the phase line in the current implementation? I think its nice to have it there all the time, as long as its not dominant. I think having the phase line there will remind people that the effects of filters are never as simple as removing selected frequencies. .hc ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list
Re: [PD] algorithms for drawing filter response curves
On Wed, Feb 16, 2011 at 1:53 AM, Hans-Christoph Steiner h...@at.or.at wrote: Ok, I got it working in a limited way as a Pd object and I was controlling my first filter against noise! Good fun. You can still run the .tcl file as a standalone GUI for dev work. Get it from my git: https://github.com/pd-projects/filterview It would be quite nice if the phase was drawn as a thin line over the magnatude graph. What do you think? .hc Hi Hans, This is a great addition to pd! I'm having a little trouble getting it to work properly, though. When I drag the filter window I get the error message 'invalid command name pdsend '. I just built it and copied the external binary into my pd path, then opened the help patch. thanks, Spencer ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list
Re: [PD] algorithms for drawing filter response curves
Nice, it works for me! I'll take a stab at making it work as a Pd object now, I'll try tonight. .hc On Tue, 2011-02-15 at 18:31 -0500, Mike Moser-Booth wrote: Hey Hans, Here's an update of filterview. There are now procs for the following filters: lowpass highpass allpass bandpass resonant peaking highshelf lowshelf I've added some lines to show the phase response (you have to comment out line 135 and uncomment 136 to see it). I also adjust the bandwidth calculations so the handles sit where they should (i.e. -3dB for bandpass/notch/etc., 1/2 power for peaking/shelf). btw, the frequency axis is log-scaled, though it could probably be improved a little. I sort of took a Pd approach to it by making an mtof proc, so the x-axis gets scaled to linear midi notes and converted to log-frequencies. :-) There might be a simpler way to do it. It also doesn't go all the way down to 0 Hz, because doing that with this approach causes the lowest frequencies to take up too much of the graph. I think Max gets around it by using a more compressed scale below 1-2 Hz. .mmb On Thu, Feb 10, 2011 at 12:39 AM, Mike Moser-Booth mmoserbo...@gmail.com wrote: Sure, I can throw the others together. Now that one is done the rest should fall into place pretty easily. It might take me a couple of days to get to it, though. .mmb On Wed, Feb 9, 2011 at 11:47 PM, Hans-Christoph Steiner h...@at.or.at wrote: That's awesome, thanks! I committed it under your name: https://github.com/pd-projects/filterview I'd like to implement all of the relevant filters, which algorithms should I use? Or even better, perhaps you want to take a crack at it while I figure out how to display the x/frequency on a log scale :-D .hc -- Mike Moser-Booth mmoserbo...@gmail.com -- Mike Moser-Booth mmoserbo...@gmail.com ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list
Re: [PD] algorithms for drawing filter response curves
Ok, I got it working in a limited way as a Pd object and I was controlling my first filter against noise! Good fun. You can still run the .tcl file as a standalone GUI for dev work. Get it from my git: https://github.com/pd-projects/filterview It would be quite nice if the phase was drawn as a thin line over the magnatude graph. What do you think? .hc On Feb 15, 2011, at 6:31 PM, Mike Moser-Booth wrote: Hey Hans, Here's an update of filterview. There are now procs for the following filters: lowpass highpass allpass bandpass resonant peaking highshelf lowshelf I've added some lines to show the phase response (you have to comment out line 135 and uncomment 136 to see it). I also adjust the bandwidth calculations so the handles sit where they should (i.e. -3dB for bandpass/notch/etc., 1/2 power for peaking/shelf). btw, the frequency axis is log-scaled, though it could probably be improved a little. I sort of took a Pd approach to it by making an mtof proc, so the x-axis gets scaled to linear midi notes and converted to log-frequencies. :-) There might be a simpler way to do it. It also doesn't go all the way down to 0 Hz, because doing that with this approach causes the lowest frequencies to take up too much of the graph. I think Max gets around it by using a more compressed scale below 1-2 Hz. .mmb On Thu, Feb 10, 2011 at 12:39 AM, Mike Moser-Booth mmoserbo...@gmail.com wrote: Sure, I can throw the others together. Now that one is done the rest should fall into place pretty easily. It might take me a couple of days to get to it, though. .mmb On Wed, Feb 9, 2011 at 11:47 PM, Hans-Christoph Steiner h...@at.or.at wrote: That's awesome, thanks! I committed it under your name: https://github.com/pd-projects/filterview I'd like to implement all of the relevant filters, which algorithms should I use? Or even better, perhaps you want to take a crack at it while I figure out how to display the x/frequency on a log scale :-D .hc -- Mike Moser-Booth mmoserbo...@gmail.com -- Mike Moser-Booth mmoserbo...@gmail.com filterview.mmb.tcl.zip Programs should be written for people to read, and only incidentally for machines to execute. - from Structure and Interpretation of Computer Programs ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list
Re: [PD] algorithms for drawing filter response curves
On Feb 7, 2011, at 3:05 PM, cyrille henry wrote: Le 07/02/2011 20:50, Hans-Christoph Steiner a écrit : ... I like that [bq~] has audio inputs, yep, that's very useful. but can you send a list of them to the first inlet, like [biquad~]? no, you need an unpack f f f f f... i think to add this functionality should not be to hard, but do you really need it? Its what [biquad~] uses, so other objects expect that, like the filter calcs in ggee. Plus this new filterview object I'm working on would output a list, and using a list means making just a single connection rather than 5. ok. here is bq_list~ is that what you wanted? If you want this filterview GUI to easily control your object, then yes, it should accept a list of biquad coefficients. .hc c .hc I spent 33 years and four months in active military service and during that period I spent most of my time as a high class muscle man for Big Business, for Wall Street and the bankers. - General Smedley Butler bq_list.zip The arc of history bends towards justice. - Dr. Martin Luther King, Jr. ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list
Re: [PD] algorithms for drawing filter response curves
That's awesome, thanks! I committed it under your name: https://github.com/pd-projects/filterview I'd like to implement all of the relevant filters, which algorithms should I use? Or even better, perhaps you want to take a crack at it while I figure out how to display the x/frequency on a log scale :-D .hc On Feb 9, 2011, at 11:07 PM, Mike Moser-Booth wrote: Hey Hans, I had some time to go over this today, and I think I've got the response working. I didn't document my changes as I went along (sorry), but I think I remembered them all and wrote them at the top of the attached script. Also, I should take back what I said earlier about the bandwidth. Given this gui, it makes sense for it to be BW. .mmb On Tue, Feb 8, 2011 at 12:08 AM, Hans-Christoph Steiner h...@at.or.at wrote: I'll check out the settings. As for running this, its a script, you can just run it on the Terminal. On GNU/Linux, it should just work. On Mac OS X, you'll probably need to have run it like this: /usr/bin/wish filterview.tcl .hc On Feb 7, 2011, at 11:20 PM, Mike Moser-Booth wrote: I don't really know how to test this and I don't really know tcl, but I tried looking at the code to see if I could make some sense of it anyway, because why the hell not. ;-) Anyway, the only part I really understood was the calculation of the coefficients, and I noticed something wrong. You are calculating alpha for bandwidth instead of Q. I'm guessing you're just borrowing what is in the ggee externals (given the code's comments), because it's done the same way there, but it's not really conventional for a lowpass filter. That's really more for bandpass, notch, and peaking filters. Using Q is also a simpler calculation: alpha = sin(omega)/ (2*Q). With Q set to .7071 (or -3 dBfs), you have a filter with no resonance, which makes sense because the cutoff frequency for a lowpass filter is defined as the frequency where the response falls be 3 dB. This is also how Max's [filtergraph~] works. It's all defined here in Robert Bristow-Johnson's Cookbook: http://www.musicdsp.org/files/Audio-EQ-Cookbook.txt The ggee externals, as far as I can tell, are all based on this cookbook, though with mistakes like using BW instead of Q. Hope that helps, .mmb On Mon, Feb 7, 2011 at 10:03 PM, Hans-Christoph Steiner h...@at.or.at wrote: On Feb 7, 2011, at 8:35 PM, Spencer Russell wrote: On Sun, Feb 6, 2011 at 11:15 PM, Mathieu Bouchard ma...@artengine.ca wrote: On Sun, 6 Feb 2011, Spencer Russell wrote: [1] gives the magnitude frequency response given the biquad coefficents, and it linked to from several places around the net. Is this the sort of thing you're looking for? [1] http://bit.ly/eFck4j This link got me directly to : USB complete: everything you need to develop custom USB peripherals Par Jan Axelson Chapitre 12 Page 364 and nothing else. (??) Whoops, I meant to send this: http://bit.ly/gUCBu4. Sorry. Here he's basically just taken the transfer function of a biquad and made the z = exp(j*w/Fs) as Mike suggested, followed by taking the magnitude and log-scaling for dB, but he's done the algebraic legwork. Just note that w (lower-case omega) is 2*pi*f and you should be good to go. He's also done some trig-substitution for more numerical precision. I'm making good progress, but now am getting lost in the filter math meeting the pixel math. Can someone mathy check my math? Or even try it out? https://github.com/pd-projects/filterview .hc ¡El pueblo unido jamás será vencido! ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list -- Mike Moser-Booth mmoserbo...@gmail.com A cellphone to me is just an opportunity to be irritated wherever you are. - Linus Torvalds -- Mike Moser-Booth mmoserbo...@gmail.com filterview.mmb.tcl.zip I hate it when they say, He gave his life for his country. Nobody gives their life for anything. We steal the lives of these kids. - Admiral Gene LeRocque ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list
Re: [PD] algorithms for drawing filter response curves
Sure, I can throw the others together. Now that one is done the rest should fall into place pretty easily. It might take me a couple of days to get to it, though. .mmb On Wed, Feb 9, 2011 at 11:47 PM, Hans-Christoph Steiner h...@at.or.atwrote: That's awesome, thanks! I committed it under your name: https://github.com/pd-projects/filterview I'd like to implement all of the relevant filters, which algorithms should I use? Or even better, perhaps you want to take a crack at it while I figure out how to display the x/frequency on a log scale :-D .hc -- Mike Moser-Booth mmoserbo...@gmail.com ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list
Re: [PD] algorithms for drawing filter response curves
On 07.02.2011, at 00:12, Hans-Christoph Steiner wrote: I've started to write a GUI for generating biquad coefficients (something like Max/MSP's [filtergraph~]). I've gotten the GUI interaction working well, now I'm looking for the algorithms for generating a plot of the frequency response of a given set of biquad coefficents? It'll end up being Tcl, but I can easily read C, Csound, Java, Perl, Python, etc. .hc i've been using the attached js file to query amplitude and phase response of biquad coeffs, where the coeffs are expected to be of the form: y[n] = a0 * x[n] + a1 * x[n-1] + a2 * x[n-2] - b1 * y[n-1] - b2 * y[n-2] (like in maxmsp). so, you'd have to rearrage the coeffs and turn the sign of the fb coeffs to make it work with the pd biquad~. vb queryBiquad.js Description: JavaScript source ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list
Re: [PD] algorithms for drawing filter response curves
2011/2/6 Hans-Christoph Steiner h...@at.or.at: I've started to write a GUI for generating biquad coefficients (something like Max/MSP's [filtergraph~]). I've gotten the GUI interaction working well, now I'm looking for the algorithms for generating a plot of the frequency response of a given set of biquad coefficents? It'll end up being Tcl, but I can easily read C, Csound, Java, Perl, Python, etc. Hey Hans, Take a look in the wslib SC Quarks, it is implemented there. ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list
Re: [PD] algorithms for drawing filter response curves
Le 07/02/2011 12:12, volker böhm a écrit : On 07.02.2011, at 00:12, Hans-Christoph Steiner wrote: I've started to write a GUI for generating biquad coefficients (something like Max/MSP's [filtergraph~]). I've gotten the GUI interaction working well, now I'm looking for the algorithms for generating a plot of the frequency response of a given set of biquad coefficents? It'll end up being Tcl, but I can easily read C, Csound, Java, Perl, Python, etc. .hc i've been using the attached js file to query amplitude and phase response of biquad coeffs, where the coeffs are expected to be of the form: y[n] = a0 * x[n] + a1 * x[n-1] + a2 * x[n-2] - b1 * y[n-1] - b2 * y[n-2] (like in maxmsp). so, you'd have to rearrage the coeffs and turn the sign of the fb coeffs to make it work with the pd biquad~. or use bq~ from nusmuk-audio lib. cyrille vb ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list
Re: [PD] algorithms for drawing filter response curves
On Feb 7, 2011, at 6:36 AM, cyrille henry wrote: Le 07/02/2011 12:12, volker böhm a écrit : On 07.02.2011, at 00:12, Hans-Christoph Steiner wrote: I've started to write a GUI for generating biquad coefficients (something like Max/MSP's [filtergraph~]). I've gotten the GUI interaction working well, now I'm looking for the algorithms for generating a plot of the frequency response of a given set of biquad coefficents? It'll end up being Tcl, but I can easily read C, Csound, Java, Perl, Python, etc. .hc i've been using the attached js file to query amplitude and phase response of biquad coeffs, where the coeffs are expected to be of the form: y[n] = a0 * x[n] + a1 * x[n-1] + a2 * x[n-2] - b1 * y[n-1] - b2 * y[n-2] (like in maxmsp). so, you'd have to rearrage the coeffs and turn the sign of the fb coeffs to make it work with the pd biquad~. or use bq~ from nusmuk-audio lib. I like that [bq~] has audio inputs, but can you send a list of them to the first inlet, like [biquad~]? .hc http://at.or.at/hans/ ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list
Re: [PD] algorithms for drawing filter response curves
On Feb 7, 2011, at 6:12 AM, volker böhm wrote: On 07.02.2011, at 00:12, Hans-Christoph Steiner wrote: I've started to write a GUI for generating biquad coefficients (something like Max/MSP's [filtergraph~]). I've gotten the GUI interaction working well, now I'm looking for the algorithms for generating a plot of the frequency response of a given set of biquad coefficents? It'll end up being Tcl, but I can easily read C, Csound, Java, Perl, Python, etc. .hc i've been using the attached js file to query amplitude and phase response of biquad coeffs, where the coeffs are expected to be of the form: y[n] = a0 * x[n] + a1 * x[n-1] + a2 * x[n-2] - b1 * y[n-1] - b2 * y[n-2] (like in maxmsp). so, you'd have to rearrage the coeffs and turn the sign of the fb coeffs to make it work with the pd biquad~. vb queryBiquad.js Thanks, that helped. Here's what I have so far: I got the mouse interaction almost completed, now I'm just starting the plotting part, which has a ways to go. .hc filterview.tcl Description: Binary data Access to computers should be unlimited and total. - the hacker ethic ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list
Re: [PD] algorithms for drawing filter response curves
On Feb 7, 2011, at 12:43 PM, Hans-Christoph Steiner wrote: On Feb 7, 2011, at 6:12 AM, volker böhm wrote: On 07.02.2011, at 00:12, Hans-Christoph Steiner wrote: I've started to write a GUI for generating biquad coefficients (something like Max/MSP's [filtergraph~]). I've gotten the GUI interaction working well, now I'm looking for the algorithms for generating a plot of the frequency response of a given set of biquad coefficents? It'll end up being Tcl, but I can easily read C, Csound, Java, Perl, Python, etc. .hc i've been using the attached js file to query amplitude and phase response of biquad coeffs, where the coeffs are expected to be of the form: y[n] = a0 * x[n] + a1 * x[n-1] + a2 * x[n-2] - b1 * y[n-1] - b2 * y[n-2] (like in maxmsp). so, you'd have to rearrage the coeffs and turn the sign of the fb coeffs to make it work with the pd biquad~. vb queryBiquad.js Thanks, that helped. Here's what I have so far: I got the mouse interaction almost completed, now I'm just starting the plotting part, which has a ways to go. .hc filterview.tcl I also just pushed my git to a public repo: https://github.com/pd-projects/filterview .hc If nature has made any one thing less susceptible than all others of exclusive property, it is the action of the thinking power called an idea, which an individual may exclusively possess as long as he keeps it to himself; but the moment it is divulged, it forces itself into the possession of everyone, and the receiver cannot dispossess himself of it.- Thomas Jefferson ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list
Re: [PD] algorithms for drawing filter response curves
On 06/02/11 23:12, Hans-Christoph Steiner wrote: now I'm looking for the algorithms for generating a plot of the frequency response of a given set of biquad coefficents? See perhaps: http://www-users.cs.york.ac.uk/~fisher/mkfilter/ In particular: http://www-users.cs.york.ac.uk/~fisher/software/mkfilter/current/complex.C global complex evaluate(complex topco[], int nz, complex botco[], int np, complex z) http://www-users.cs.york.ac.uk/~fisher/software/mkfilter/current/genplot.C static void computefr(complex fr[], int nsteps) Claude ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list
Re: [PD] algorithms for drawing filter response curves
Le 07/02/2011 18:40, Hans-Christoph Steiner a écrit : On Feb 7, 2011, at 6:36 AM, cyrille henry wrote: Le 07/02/2011 12:12, volker böhm a écrit : On 07.02.2011, at 00:12, Hans-Christoph Steiner wrote: I've started to write a GUI for generating biquad coefficients (something like Max/MSP's [filtergraph~]). I've gotten the GUI interaction working well, now I'm looking for the algorithms for generating a plot of the frequency response of a given set of biquad coefficents? It'll end up being Tcl, but I can easily read C, Csound, Java, Perl, Python, etc. .hc i've been using the attached js file to query amplitude and phase response of biquad coeffs, where the coeffs are expected to be of the form: y[n] = a0 * x[n] + a1 * x[n-1] + a2 * x[n-2] - b1 * y[n-1] - b2 * y[n-2] (like in maxmsp). so, you'd have to rearrage the coeffs and turn the sign of the fb coeffs to make it work with the pd biquad~. or use bq~ from nusmuk-audio lib. I like that [bq~] has audio inputs, yep, that's very useful. but can you send a list of them to the first inlet, like [biquad~]? no, you need an unpack f f f f f... i think to add this functionality should not be to hard, but do you really need it? C .hc http://at.or.at/hans/ ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list
Re: [PD] algorithms for drawing filter response curves
On Feb 7, 2011, at 2:39 PM, cyrille henry wrote: Le 07/02/2011 18:40, Hans-Christoph Steiner a écrit : On Feb 7, 2011, at 6:36 AM, cyrille henry wrote: Le 07/02/2011 12:12, volker böhm a écrit : On 07.02.2011, at 00:12, Hans-Christoph Steiner wrote: I've started to write a GUI for generating biquad coefficients (something like Max/MSP's [filtergraph~]). I've gotten the GUI interaction working well, now I'm looking for the algorithms for generating a plot of the frequency response of a given set of biquad coefficents? It'll end up being Tcl, but I can easily read C, Csound, Java, Perl, Python, etc. .hc i've been using the attached js file to query amplitude and phase response of biquad coeffs, where the coeffs are expected to be of the form: y[n] = a0 * x[n] + a1 * x[n-1] + a2 * x[n-2] - b1 * y[n-1] - b2 * y[n-2] (like in maxmsp). so, you'd have to rearrage the coeffs and turn the sign of the fb coeffs to make it work with the pd biquad~. or use bq~ from nusmuk-audio lib. I like that [bq~] has audio inputs, yep, that's very useful. but can you send a list of them to the first inlet, like [biquad~]? no, you need an unpack f f f f f... i think to add this functionality should not be to hard, but do you really need it? Its what [biquad~] uses, so other objects expect that, like the filter calcs in ggee. Plus this new filterview object I'm working on would output a list, and using a list means making just a single connection rather than 5. .hc I spent 33 years and four months in active military service and during that period I spent most of my time as a high class muscle man for Big Business, for Wall Street and the bankers. - General Smedley Butler ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list
Re: [PD] algorithms for drawing filter response curves
On 07.02.2011, at 00:12, Hans-Christoph Steiner wrote: I've started to write a GUI for generating biquad coefficients (something like Max/MSP's [filtergraph~]). I've gotten the GUI interaction working well, now I'm looking for the algorithms for generating a plot of the frequency response of a given set of biquad coefficents? It'll end up being Tcl, but I can easily read C, Csound, Java, Perl, Python, etc. Actually, why don't you push a [sig~ 1] through a [rifft~] and use that as a probe with which you will connect to a spectrogram patch ? (the probe's [rifft~] and the spectrogram's [fft~] have to use the same block size.) ___ | Mathieu Bouchard tél: +1.514.383.3801 Villeray, Montréal, QC ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list
Re: [PD] algorithms for drawing filter response curves
On Feb 7, 2011, at 3:33 PM, Mathieu Bouchard wrote: On 07.02.2011, at 00:12, Hans-Christoph Steiner wrote: I've started to write a GUI for generating biquad coefficients (something like Max/MSP's [filtergraph~]). I've gotten the GUI interaction working well, now I'm looking for the algorithms for generating a plot of the frequency response of a given set of biquad coefficents? It'll end up being Tcl, but I can easily read C, Csound, Java, Perl, Python, etc. Actually, why don't you push a [sig~ 1] through a [rifft~] and use that as a probe with which you will connect to a spectrogram patch ? (the probe's [rifft~] and the spectrogram's [fft~] have to use the same block size.) Because I'm doing this in Tcl... Its a GUI object. .hc It is convenient to imagine a power beyond us because that means we don't have to examine our own lives., from The Idols of Environmentalism, by Curtis White ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list
Re: [PD] algorithms for drawing filter response curves
On Sun, Feb 6, 2011 at 11:15 PM, Mathieu Bouchard ma...@artengine.ca wrote: On Sun, 6 Feb 2011, Spencer Russell wrote: [1] gives the magnitude frequency response given the biquad coefficents, and it linked to from several places around the net. Is this the sort of thing you're looking for? [1] http://bit.ly/eFck4j This link got me directly to : USB complete: everything you need to develop custom USB peripherals Par Jan Axelson Chapitre 12 Page 364 and nothing else. (??) Whoops, I meant to send this: http://bit.ly/gUCBu4. Sorry. Here he's basically just taken the transfer function of a biquad and made the z = exp(j*w/Fs) as Mike suggested, followed by taking the magnitude and log-scaling for dB, but he's done the algebraic legwork. Just note that w (lower-case omega) is 2*pi*f and you should be good to go. He's also done some trig-substitution for more numerical precision. -s ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list
Re: [PD] algorithms for drawing filter response curves
On Feb 7, 2011, at 8:35 PM, Spencer Russell wrote: On Sun, Feb 6, 2011 at 11:15 PM, Mathieu Bouchard ma...@artengine.ca wrote: On Sun, 6 Feb 2011, Spencer Russell wrote: [1] gives the magnitude frequency response given the biquad coefficents, and it linked to from several places around the net. Is this the sort of thing you're looking for? [1] http://bit.ly/eFck4j This link got me directly to : USB complete: everything you need to develop custom USB peripherals Par Jan Axelson Chapitre 12 Page 364 and nothing else. (??) Whoops, I meant to send this: http://bit.ly/gUCBu4. Sorry. Here he's basically just taken the transfer function of a biquad and made the z = exp(j*w/Fs) as Mike suggested, followed by taking the magnitude and log-scaling for dB, but he's done the algebraic legwork. Just note that w (lower-case omega) is 2*pi*f and you should be good to go. He's also done some trig-substitution for more numerical precision. I'm making good progress, but now am getting lost in the filter math meeting the pixel math. Can someone mathy check my math? Or even try it out? https://github.com/pd-projects/filterview .hc ¡El pueblo unido jamás será vencido! ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list
Re: [PD] algorithms for drawing filter response curves
I don't really know how to test this and I don't really know tcl, but I tried looking at the code to see if I could make some sense of it anyway, because why the hell not. ;-) Anyway, the only part I really understood was the calculation of the coefficients, and I noticed something wrong. You are calculating alpha for bandwidth instead of Q. I'm guessing you're just borrowing what is in the ggee externals (given the code's comments), because it's done the same way there, but it's not really conventional for a lowpass filter. That's really more for bandpass, notch, and peaking filters. Using Q is also a simpler calculation: alpha = sin(omega)/(2*Q). With Q set to .7071 (or -3 dBfs), you have a filter with no resonance, which makes sense because the cutoff frequency for a lowpass filter is defined as the frequency where the response falls be 3 dB. This is also how Max's [filtergraph~] works. It's all defined here in Robert Bristow-Johnson's Cookbook: http://www.musicdsp.org/files/Audio-EQ-Cookbook.txt The ggee externals, as far as I can tell, are all based on this cookbook, though with mistakes like using BW instead of Q. Hope that helps, .mmb On Mon, Feb 7, 2011 at 10:03 PM, Hans-Christoph Steiner h...@at.or.atwrote: On Feb 7, 2011, at 8:35 PM, Spencer Russell wrote: On Sun, Feb 6, 2011 at 11:15 PM, Mathieu Bouchard ma...@artengine.ca wrote: On Sun, 6 Feb 2011, Spencer Russell wrote: [1] gives the magnitude frequency response given the biquad coefficents, and it linked to from several places around the net. Is this the sort of thing you're looking for? [1] http://bit.ly/eFck4j This link got me directly to : USB complete: everything you need to develop custom USB peripherals Par Jan Axelson Chapitre 12 Page 364 and nothing else. (??) Whoops, I meant to send this: http://bit.ly/gUCBu4. Sorry. Here he's basically just taken the transfer function of a biquad and made the z = exp(j*w/Fs) as Mike suggested, followed by taking the magnitude and log-scaling for dB, but he's done the algebraic legwork. Just note that w (lower-case omega) is 2*pi*f and you should be good to go. He's also done some trig-substitution for more numerical precision. I'm making good progress, but now am getting lost in the filter math meeting the pixel math. Can someone mathy check my math? Or even try it out? https://github.com/pd-projects/filterview .hc ¡El pueblo unido jamás será vencido! ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list -- Mike Moser-Booth mmoserbo...@gmail.com ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list
Re: [PD] algorithms for drawing filter response curves
I'll check out the settings. As for running this, its a script, you can just run it on the Terminal. On GNU/Linux, it should just work. On Mac OS X, you'll probably need to have run it like this: /usr/bin/wish filterview.tcl .hc On Feb 7, 2011, at 11:20 PM, Mike Moser-Booth wrote: I don't really know how to test this and I don't really know tcl, but I tried looking at the code to see if I could make some sense of it anyway, because why the hell not. ;-) Anyway, the only part I really understood was the calculation of the coefficients, and I noticed something wrong. You are calculating alpha for bandwidth instead of Q. I'm guessing you're just borrowing what is in the ggee externals (given the code's comments), because it's done the same way there, but it's not really conventional for a lowpass filter. That's really more for bandpass, notch, and peaking filters. Using Q is also a simpler calculation: alpha = sin(omega)/(2*Q). With Q set to .7071 (or -3 dBfs), you have a filter with no resonance, which makes sense because the cutoff frequency for a lowpass filter is defined as the frequency where the response falls be 3 dB. This is also how Max's [filtergraph~] works. It's all defined here in Robert Bristow-Johnson's Cookbook: http://www.musicdsp.org/files/Audio-EQ-Cookbook.txt The ggee externals, as far as I can tell, are all based on this cookbook, though with mistakes like using BW instead of Q. Hope that helps, .mmb On Mon, Feb 7, 2011 at 10:03 PM, Hans-Christoph Steiner h...@at.or.at wrote: On Feb 7, 2011, at 8:35 PM, Spencer Russell wrote: On Sun, Feb 6, 2011 at 11:15 PM, Mathieu Bouchard ma...@artengine.ca wrote: On Sun, 6 Feb 2011, Spencer Russell wrote: [1] gives the magnitude frequency response given the biquad coefficents, and it linked to from several places around the net. Is this the sort of thing you're looking for? [1] http://bit.ly/eFck4j This link got me directly to : USB complete: everything you need to develop custom USB peripherals Par Jan Axelson Chapitre 12 Page 364 and nothing else. (??) Whoops, I meant to send this: http://bit.ly/gUCBu4. Sorry. Here he's basically just taken the transfer function of a biquad and made the z = exp(j*w/Fs) as Mike suggested, followed by taking the magnitude and log-scaling for dB, but he's done the algebraic legwork. Just note that w (lower-case omega) is 2*pi*f and you should be good to go. He's also done some trig-substitution for more numerical precision. I'm making good progress, but now am getting lost in the filter math meeting the pixel math. Can someone mathy check my math? Or even try it out? https://github.com/pd-projects/filterview .hc ¡El pueblo unido jamás será vencido! ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list -- Mike Moser-Booth mmoserbo...@gmail.com A cellphone to me is just an opportunity to be irritated wherever you are. - Linus Torvalds ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list
Re: [PD] algorithms for drawing filter response curves
[1] gives the magnitude frequency response given the biquad coefficents, and it linked to from several places around the net. Is this the sort of thing you're looking for? [1] http://bit.ly/eFck4j -s On Sun, Feb 6, 2011 at 6:12 PM, Hans-Christoph Steiner h...@at.or.at wrote: I've started to write a GUI for generating biquad coefficients (something like Max/MSP's [filtergraph~]). I've gotten the GUI interaction working well, now I'm looking for the algorithms for generating a plot of the frequency response of a given set of biquad coefficents? It'll end up being Tcl, but I can easily read C, Csound, Java, Perl, Python, etc. .hc All mankind is of one author, and is one volume; when one man dies, one chapter is not torn out of the book, but translated into a better language; and every chapter must be so translated -John Donne ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list
Re: [PD] algorithms for drawing filter response curves
On Sun, 6 Feb 2011, Spencer Russell wrote: [1] gives the magnitude frequency response given the biquad coefficents, and it linked to from several places around the net. Is this the sort of thing you're looking for? [1] http://bit.ly/eFck4j This link got me directly to : USB complete: everything you need to develop custom USB peripherals Par Jan Axelson Chapitre 12 Page 364 and nothing else. (??) ___ | Mathieu Bouchard tél: +1.514.383.3801 Villeray, Montréal, QC___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list
Re: [PD] algorithms for drawing filter response curves
On Sun, 6 Feb 2011, Hans-Christoph Steiner wrote: I've started to write a GUI for generating biquad coefficients (something like Max/MSP's [filtergraph~]). I've gotten the GUI interaction working well, now I'm looking for the algorithms for generating a plot of the frequency response of a given set of biquad coefficents? It'll end up being Tcl, but I can easily read C, Csound, Java, Perl, Python, etc. I made a rather simple patch that measures the frequency response of any linear filter of your choice (convolution, lop, hip, bp, biquad, etc.) by using FFT. I demonstrated it at Pd Convention 2007. http://gridflow.ca/gallery/operator_spectrum.png except it only works for image filters, not sound. It plots an image filter's spectrum like a topographic map for all combinations of horiz-frequencies and vert-frequencies at once. (however, it assumes that the effect is wrap-around, just like a FFT is wrap-around) ___ | Mathieu Bouchard tél: +1.514.383.3801 Villeray, Montréal, QC ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list
Re: [PD] algorithms for drawing filter response curves
I don't know if this is what you're asking, but iirc it's really just a matter of substituting exp(j*2*pi*fc/Fs) for z in the transfer function. I can send a Pd patch illustrating it later, if you like. .mmb On Sunday, February 6, 2011, Hans-Christoph Steiner h...@at.or.at wrote: I've started to write a GUI for generating biquad coefficients (something like Max/MSP's [filtergraph~]). I've gotten the GUI interaction working well, now I'm looking for the algorithms for generating a plot of the frequency response of a given set of biquad coefficents? It'll end up being Tcl, but I can easily read C, Csound, Java, Perl, Python, etc. .hc All mankind is of one author, and is one volume; when one man dies, one chapter is not torn out of the book, but translated into a better language; and every chapter must be so translated -John Donne ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list -- Mike Moser-Booth mmoserbo...@gmail.com ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list
Re: [PD] algorithms for drawing filter response curves
Sorry, sent that a little too quickly. I should've also mentioned that fc=cutoff frequency and Fs=sample rate. And the magnitude of the result will give the magnitude frequency response and the angle will give the phase response. .mmb On Monday, February 7, 2011, Mike Moser-Booth mmoserbo...@gmail.com wrote: I don't know if this is what you're asking, but iirc it's really just a matter of substituting exp(j*2*pi*fc/Fs) for z in the transfer function. I can send a Pd patch illustrating it later, if you like. .mmb On Sunday, February 6, 2011, Hans-Christoph Steiner h...@at.or.at wrote: I've started to write a GUI for generating biquad coefficients (something like Max/MSP's [filtergraph~]). I've gotten the GUI interaction working well, now I'm looking for the algorithms for generating a plot of the frequency response of a given set of biquad coefficents? It'll end up being Tcl, but I can easily read C, Csound, Java, Perl, Python, etc. .hc All mankind is of one author, and is one volume; when one man dies, one chapter is not torn out of the book, but translated into a better language; and every chapter must be so translated -John Donne ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list -- Mike Moser-Booth mmoserbo...@gmail.com -- Mike Moser-Booth mmoserbo...@gmail.com ___ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management - http://lists.puredata.info/listinfo/pd-list
