- chuck-users - lists.cs.princeton.edu

Virtual Audio World (VAW)
by Les Hall 17 Jun '11

17 Jun '11

I have decided to create a ChucK-based distributed virtual audio world. In this world we will have places which are physically located on each other's computers and virtually located throughout cyberspace. The first place in this world will be on my Mac mini. I have received permission to use five of the public streaming ports on radio.electro-music.com for this world temporarily. In the event that it grows, we will address the issue of expansion with electro-music server resources, however this world will not be restricted in any way other than morally, ethically, and legally as appropriate. This means that if you have streaming resources you may use them as well. The focal point for discussion of this virtual audio world will be a thread that I just started on the ChucK forum of electro-music.com. The thread is here: http://electro-music.com/forum/viewtopic.php?t=48042 Tonight I will set up a two-channel version of this world so that I and up to two guests can participate as soon as possible. It will use public ports public_1, public_2, and public_3, the latter two of which are for guests of my place in this world. I will post full information of the admittedly somewhat complex task of setting up for streaming into this world in the thread linked above. I openly invite your participation. Les (Inventor)

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sleep sort port
by Kassen 16 Jun '11

16 Jun '11

Fellow ChucKists, I just noticed this sorting algorithm; http://dis.4chan.org/read/prog/1295544154 (should be work-safe, despite that URL) for those afraid of 4chan links and for reference, here is it; #!/bin/bash function f() { sleep "$1" echo "$1" } while [ -n "$1" ] do f "$1" & shift done wait example usage: ./sleepsort.bash 5 3 6 3 6 3 1 4 7 Since this is time-based and also spectacularly impractical it should be of acute interest to present company. I therefore ported this to ChucK which was so far lacking a sorting algorithm that is consistent with our time-centric approach to programming. ----------------------8<------------------------------------- int input[8]; for (int n; n< input.size(); n++) Std.rand2(0, 20) => input[n]; int output[false]; fun void arrayPrinter( int arg[] ) { for (int n; n < arg.size(); n++) chout <= arg[n] <= " "; chout <= IO.newline(); } fun void waiter(int length) { length::second => now; output << length; } arrayPrinter(input); for (int n; n< input.size(); n++) spork~waiter(input[n]); while (output.size() < input.size()) second => now; arrayPrinter(output); ---------------------------------------------8<---------------------------------- This will display a list of random numbers, spends some time on sorting them, then displays the numbers again, but sorted. Hope that's good for a smile for some. Yours, Kas.

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Assigning tasks to keys
by Timothy Leonido 13 Jun '11

13 Jun '11

Hey All, In the theme of the "key organ" example patch, I'm wondering how to assign more varied tasks to my keyboard. Rather than give the keyboard a midi-type of access to scales, I'd like to have different keys control different aspects of loops, such as sample rate control (or if "r" could increase the reverb on a loop while it's in action). Please let me know if you have any advice on this one... Thanks! Tim

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Tracking down clicks and pops..
by Johnathan Bell 13 Jun '11

13 Jun '11

I'm working on a subtractive synthesis program written in ChucK, and I'm not sure, I may have sporked one too many threads, it may be that I'm just not resetting some parameter, but I'm getting some clicking noises in my latest program... I guess my first question is in general, what would cause a clicking or popping noise first of all... The synth is three square waves, slightly detuned and out of phase with each other, and there's a high-to-low LPF and HPF filter acting on the note as it attacks and decays, but it seems to only click *sometimes* and specifically when I hit a low note and then go up to a high note. If I disable filter sweeping entirely, it seems to get rid of some of the clicks, but not all of them. The program is based on the example "polyfony.ck" but it's quite a bit larger now (approx 700+ lines)... Some other notes of concern, each note handler thread (of which there are 20) sporks it's own threads to modulate some parameters, so being 20 note handlers + three threads per note handler + a few other threads (such as the midi watcher), I've got almost 90 threads running at one time, could that be part of the issue? - Johnathan

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New Thread: DSP in ChucK
by Perry Cook 11 Jun '11

11 Jun '11

Yo all, Based on discussions of DSP in ChucK, I thought I'd split it out into a new thread. The last time I taught my music DSP intro course (COS325 Transforming Reality Through Computer, named long ago by Paul Lansky and Ken Steiglitz when they taught it on NeXT Machines!!), I taught it in STK AND ChucK (with just a touch of MATLAB for completeness). Most all examples are provided in C, C++ (via STK), and ChucK. http://www.cs.princeton.edu/courses/archive/spr09/cos325/ Lately I've been doing a lot of intro ChucK lecturing (Cal Arts, ASU, etc.) and have been showing them how to do things in at least 3 ways: 1) Directly in the Language 2) Using built-in Unit Generators (example, building a flute from delay lines) 3) Using higher-level built-in Unit Generators (example, using the Flute UG) For example, a two-pole feedback filter can be done directly in the language, with arrays, and Step for output: // ***************************************** // Two Pole Resonator directly in ChucK Noise n => Gain input => blackhole; Step output => dac; [0.0, 0.0] @=> float outputs[]; [-1.977755, 0.998001] @=> float coeffs[]; 0.001 => input.gain; while (1) { input.last() - outputs[0]*coeffs[0] - outputs[1]*coeffs[1] => float temp; outputs[0] => outputs[1]; temp => outputs[0] => output.next; 1 :: samp => now; } // ***************************************** or with Delay unit generators (by the way, this is a way to do a UG based arbitrary order FIR/IIR filter): // ***************************************** // Two Pole Resonator using Delays Noise n => Gain output => dac; output => Gain d1 => output; // 1 sample delay output => Delay d2 => output; // 2 sample delay 1 :: samp => d2.delay; // feedback adds 1 sample of delay 1.977755 => d1.gain; -0.998001 => d2.gain; 0.001 => n.gain; while (1) { 1.0 :: second => now; } // ***************************************** Or, using the built-in TwoPole Unit Generator: // ***************************************** // Two Pole Resonator Unit Generator Noise n => TwoPole tp => dac; 1000.0 => tp.freq; 0.999 => tp.radius; 0.001 => tp.gain; while (1) { 1.0 :: second => now; } // *****************************************

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Fwd: programming of the art computer
by Kassen 11 Jun '11

11 Jun '11

Will likely be of interest to some? ---------- Forwarded message ---------- From: alex <alex(a)lurk.org> Date: 10 June 2011 13:36 Subject: [livecode] programming of the art computer To: livecode(a)toplap.org Hi all, Here's a new mailing list just starting up which might be of interest to some here, on designing programming languages for the arts: http://lists.lurk.org/mailman/listinfo/potac archive here: http://lists.lurk.org/pipermail/potac/ best wishes alex

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Setting LPF Q or Freq to very high or low values causes bad sounds...
by Johnathan Bell 10 Jun '11

10 Jun '11

I'm not sure if I'm just doing something wrong or what, but (for instance) if I set up a SawOsc => LPF => DAC and set the LPF's Q to something very low (< 0.05) with the Osc set to a frequency of 440Hz, there is some kind of blow-your-ears-out high gain garbage that comes out of the speakers... Does anyone know if (1) this is normal and (2) what are normal (sane) values for this? I get the same kind of behavior if I set the cutoff frequency to something > 12000ish. - JB

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Re: [chuck-users] Modulation of parameters "by hand"? [Yo, scott!]
by Kassen 09 Jun '11

09 Jun '11

http://cip.ablelemon.co.uk This is really nice stuff! I like Scott's usage of blackhole for making signals persistent and continuous. The usage of GUI faders to avoid clicks and for expression is really cool too. For those of us not on OSX (or not inclined to sliders); when using buses as a sort of in-out matrix like Scott does when he writes; Provides basic connectivity to busses. function void connect(int, int) we could have "connect()" place a Envelope between the two busses and have that ramp up when connecting, then down when destroying the connection. That too would avoid clicks and could create a sort of cross-fading with some extra effort. Kas.

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interesting concert (The Hague, NL)
by Kassen 09 Jun '11

09 Jun '11

Fellow ChucKists, One of your Chuckist brothers and (lurtking?) list member, Caspar Schipper, is having a concert of his piece written in ChucK; Time 23 June · 19:30 - 21:30 Location Arnold Schoenbergzaal, Koninklijk Conservatorium, Den Haag Juliana van Stolberglaan 1 Den Haag, Netherlands FB event thingy; http://www.facebook.com/event.php?eid=222298021130975 The cool thing is that all of the DSP is written in ChucK itself. I think this is the first piece of any serious length and complexity like that that I heard of. Gossip has it that Caspar will publish a bit online about this and his process, but of course it'd be nice to come by if you have the chance. So; I thought I'd post this as I think Caspar is a bit modest and this seems quite interesting; the "sonology" department at the local conservatory is quite famous and I think this is the first example of more extensive ChucK usage there. Yours, Kas.

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Modulation of parameters "by hand"? Does ChucK have a function reference data type?
by Johnathan Bell 09 Jun '11

09 Jun '11

I'm trying to create a generic "modulation" function where I can give it some parameters to set up the modulation and a property to modulate. My current way of thinking would require passing a function object into the shred so that the parameter to be modulated can be chosen at the time of the function calling... Now I know already that I can't do something like the following: --code-- // A failed attempt at tremolo SinOsc osc1 => Gain master => dac; 440 => osc1.freq; SinOsc lfo => master.gain; 5 => lfo.freq; .3 => lfo.gain; --/code-- So thus I set up this function: --code-- fun void tremolo(Gain noteGain) { SinOsc lfo => blackhole; 5.75 => lfo.freq; .3 => lfo.gain; while (true) { 1-lfo.last() => noteGain.gain; // Assume "resolution" is a dur such as 10::ms, it is the resolution of our modulation resolution => now; } } --/code-- And spork it with a gain object to modify... That works great, but I'll need to code a separate function for every single possible parameter that I'd want to modulate, so is there a way of specifying the specific parameter on the function call instead of the whole object, for instance, the prototype could be: --code-- fun void modulate(FunctionObject param) --/code-- And then the updated values would (in theory) be ChucK'ed directly to that "param" instead of object.parameter? I tried setting it up this way but I don't seem to know the object type for passing a function reference, if there is one. Or maybe someone else has a better idea that I haven't thought of? - JB

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