October 2017 - chuck-users - lists.cs.princeton.edu

DSP question: accumulating frequency info using FFT?
by Jascha Narveson 15 Oct '17

15 Oct '17

Chuck list! Help! I have the following idea and I’d like to hear what it sounds like: - play a sound into an FFT - as the FFT runs, for each bin: - - look at the magnitude info - - take a small fraction of this info and store it in a running total - - let the phase pass through unchanged - use the spectral data in the running total for the IFFT What I was hoping for was a slow emerging smear of all the frequencies from the input sound, kind of like a weird version of some kind of “infinite sustain” reverb. What I’m getting is the attacks of the original sound coming through, although fading in, and covered with noise. I think I’m doing something wrong by not doing something with the phase, but I’m not sure what. I’d love some advice… cheers, j - - - - c o d e e x a m p l e - - - - SinOsc synth => FFT fft => blackhole; UAnaBlob blob; IFFT ifft => dac; synth.freq(440); synth.gain(0.1); // set parameters 2048 => fft.size; // place to hold the FFT data as it comes in complex spec[fft.size()/2]; // place to store the accumulated FFT data, preload with zeroes complex acc[fft.size()/2]; for(0 => int i; i < acc.cap(); i++) { #(0, 0) => acc[i]; } // do it! spork ~ sawTune(); spork ~ accumulateFrequenciesViaFFT(); while (true) { 1::second => now; } fun void accumulateFrequenciesViaFFT() { while( true ) { fft.upchuck() @=> blob; // get the data blob.cvals() @=> spec; // for every bin... for(0 => int i; i < spec.cap(); i++) { // get the mag/phase for each bin by converting to polar spec[i] $ polar => polar newBin; // and get our running totals from acc acc[i] $ polar => polar accBin; // scale the inocming mag and add it to acc newBin.mag * 0.001 +=> accBin.mag; // let phase pass through newBin.phase => accBin.phase; /*Math.random2f(0, TWO_PI) => accBin.phase;*/ // convert back to complex and put back in the acc array accBin $ complex => acc[i]; } ifft.transform(acc); fft.size()::samp => now; } } fun void sawTune() { while (true) { Math.random2(48, 72) => int midinote; Math.mtof(midinote) => synth.freq; 333::ms => now; } }

2 4

Chuck Racks
by Spencer Salazar 14 Oct '17

14 Oct '17

Greetings, I would like to announce the first official beta release of Chuck Racks: http://mtiid.calarts.edu/projects/software/chuck-racks/ ChucK Racks makes it possible to write and execute ChucK programs as VST/AudioUnit plugins. The ChucK Racks architecture supports the following features: - Process incoming audio in ChucK (i.e. Audio FX plugins) - Process MIDI events from the host in ChucK programs (MIDI FX plugins) - Write synthesis plugins in ChucK that run as regular synthesizer audio plugins in a host/DAW - Synchronize clock and beat-time between a host/session and ChucK - Generate new MIDI/OSC events from ChucK (e.g. writing MIDI/OSC sequencer plugins) - Automate variables in ChucK code using host automation lanes Chuck Racks was developed by Jordan Hochenbaum, Rodrigo Sena, and myself here at CalArts. Enjoy and please feel free to let us know of any feedback! Regards, Spencer -- Spencer Salazar, PhD Special Faculty Music Technology: Interaction, Intelligence, and Design California Institute of the Arts ssalazar(a)calarts.edu | +1 831.277.4654 https://spencersalazar.com

11 12

linux build failure, qt5 support?
by Colleen Josephson 13 Oct '17

13 Oct '17

I'm trying to run 'make linux-jack' in miniAudicle1.3.5.2's source directory, and the build fails nearly immediately with: which: no qmake-qt4 in (/home/cjoseph/anaconda2/bin:/usr/local/bin:/usr/bin:/bin:/opt/bin:/usr/x86_64-pc-linux-gnu/gcc-bin/4.9.3:/usr/x86_64-pc-linux-gnu/avr/gcc-bin/4.8.2:/usr/x86_64-pc-linux-gnu/gnat-gcc-bin/4.3:/usr/libexec/gnat-gcc/x86_64-pc-linux-gnu/4.3:/usr/games/bin:/usr/local/ec2/ec2-api-tools-1.6.13.0/bin:/home/cjoseph/piran/platform_util) .... In file included from qt/mAMainWindow.cpp:25:0: qt/mAMainWindow.h:28:23: fatal error: QMainWindow: No such file or directory #include <QMainWindow> The website just specifies qt4.8+, I currently have Qt 5.6.2. Is there any QT5 support? QT5 has been out for 5 years now and it's nearly impossible to downgrade, so I am really hoping the answer is yes! Thanks, -Colleen

2 1

what exactly is tuned feedback?
by Michael Heuer 12 Oct '17

12 Oct '17

All, The Dave Smith DSM03 Feedback module has what is described as tuned feedback https://www.davesmithinstruments.com/product/dsm03-feedback-module/ I have the same question as was posted here "I'm trying to understand what 'tuned feedback' means -- does this mean the signal enters a delay line that lasts one cycle of a certain pitch? (So, say, a 50Hz sound is a 20ms delay line.) Does this end up reinforcing that pitch when you hear the sound? (I guess it would reinforce multiples of the pitch too, but less so.)" https://www.kvraudio.com/forum/viewtopic.php?p=1673572&sid=ae6a060ebaffea26… Thanks! michael

2 2