Author: Tom Zicarelli

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ep-413 week 8

More voices, granular synthesis, convolution in the frequency domain, phasors…

People acting like computers:

Fictional language dialog by Naila Burney:  https://reactivemusic.net/?p=7242

Vocoders in Max:

Phasors and granular synthesis

Phasors: https://reactivemusic.net/?p=17353

Example Max patches:
  • phasors: cosine, sine, windows: phasor-stuff.maxpat
  • playing an audio file with a phasor: graintest1-phasor-count.maxpat
  • granular synthesis: graintest3.maxpat
  • More granular synthesis: timestretch5.maxpat

Download these patches from https://github.com/tkzic/max-projects folder: granular-timestretch

More phasors

Books mentioned:

  • “Designing Sound” by Andy Farnell
  • “Computer Music Tutorial” By Chris Roads
Assignment: due in class 10/27/2014

Composition: Sound-byte 

  • The sound-byte is a short audio clip of speech.
  • The speech can come from anywhere. Something familiar, something famous, something unusual.
  • Every sound in the composition is derived only from the sound-byte. You can use any tool or method.
  • The sound-byte in its original form should occur somewhere in the piece
  • Duration: roughly 2-3 minutes?  That is up to you.
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Phasor

Engine of time.

from Wikipedia

http://en.wikipedia.org/wiki/Phasor

Unfasor

 

Traveling along the outer edge of the circle, the distance goes from 0 to 2*PI radians, then starts over again. In degrees it would be 0 to 360. A clock goes from 0 to 12. In Max and Pd the phasor~ objects are normalized to run from 0.0 to 1.0. Think of flattening out the edge of the circle to a straight line.

The phasor as input to a sine or cosine function generates one  cycle of a wave for each revolution – as shown in the above animation. For example, cosine would go from 0 to 1 to 0 to -1 to 0.

If you graph the phasor value, it looks like a sawtooth wave – rising in a ramp from 0.0 to 1.0 then falling straight down to 0.0 to start again.

With waves, the distance around the circle represents time (or phase), the projected cosine value represents amplitude.

In science…

“A phasor can be considered a vector rotating about the origin in a complex plane. The cosine function is the projection of the vector onto the real axis. Its amplitude is the modulus of the vector, and its argument is the total phase \omega t+\theta. The phase constant \thetarepresents the angle that the vector forms with the real axis at t = 0.”

-WIkipedia

In art…

“And the seasons they go round and round 
And the painted ponies go up and down 
We’re captive on the carousel of time 
We can’t return we can only look 
Behind from where we came 
And go round and round and round 
In the circle game.”

-Joni Mitchell

(These lyrics happen at about 4:40 in the video…)

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Heterodyne filter in Max

Multiply by an analytic signal to detect the frequency of a sine wave.

When the frequencies match, the sum of the real and imaginary parts will be positive.

References:

download

max-projects on Github: https://github.com/tkzic/max-projects

folder: heterodyne-filter

patch: heterodyne-test3.maxpat

 

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Spectral freeze in Max

By Jean Francois-Charles

Freeze sounds with Max MSP Jitter using FFT and Inverse FFT. For this video to be really useful, you will need to download the free Max/MSP/Jitter patches on http://www.cycling74.com/share.html
To get more “under the hood” insight, download the free article “A Tutorial for Spectral Sound Processing with Max/MSP and Jitter” http://www.mitpressjournals.org/doi/pdf/10.1162/comj.2008.32.3.87

note: local patches in tkzic/jfcharles/