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ep-413 DSP – week 14

Earth, air, fire, and water

Waves that are not sound waves.

Experiments

Transmitting music with light

light: https://reactivemusic.net/?p=8487

Analog radio/TV transmitters

A simple Arduino AM transmitter (Morse code) https://reactivemusic.net/?p=4450 (antenna pin D8) on 1.337 MHz

Raspberry Pi-rate radio. FM stereo transmitter using R-Pi and a piece of wire: http://makezine.com/projects/make-38-cameras-and-av/raspberry-pirate-radio/ Also see: https://reactivemusic.net/?p=10186

Analog TV transmitters, using RF Modulators and Old VCR’s: https://reactivemusic.net/?p=12355

Software defined Radio (SDR)

using Max and Pd

rtl-sdr – inexpensive open source software defined radio

Software defined radio in Max http://zerokidz.com/radio (The user guide http://zerokidz.com/radio/docs/maxsdr5.pdf and tutorials provide a basic introduction to working with radio signals in the audio domain.

Transmitting sound in water

Transmitting signals in water https://reactivemusic.net/?p=853

Internet radio streams and recordings

ideas

  • What is the difference between sound waves and radio waves?
  • What is an antenna?
  • Wave propagation is frequency dependent
  • Sunspots and magnetic fields http://spaceweather.com
  • Extreme frequencies, negative frequencies?

The speed of sound is 340 m/s in air (1497 m/s in water)

Speed of light is 300,000,000 m/s

wavelength = velocity / frequency

“I think [radio] is just the biggest conceptual art project uninentional or otherwise that anyone ever made. it puts Christo and those other guys to shame. Its planetary”

Roman Mars “Episode 97 – Numbers Stations” from 99% Invisible

Frequencies and modes

  • Macbook trackpad: Noise 5 mHz. (try holding radio near screen too)
  • Macbook AC adapter: Noise 600-1400 kHz. (~1000)
  • AC adapters, LED’s, Utility poles: 3.2 Khz
  • Arduino transmitter: AM 1330 kHz.
  • Laser light at 650nM
  • Wireless micorophone (Orange-brown): Wide FM 614.150 MHz. (R band)
  • Cordless phone: Narrow FM 926 mHz.
  • Cell phone: Digitally encrypted trunking FM 836 mHz.
  • Wifi: Digitally encoded PCM 2.4 gHz.
  • FM broadcast band: Wide FM 89.7 mHz (Raspberry Pi example 98.1 Mhz)
  • TV audio 600 mhz/660 mhz FMW
  • The sun http://www.ips.gov.au/Solar/3/4

Looking for more…

This blog has many stories about experiments waves. Try searching, for example, for: “radio” https://reactivemusic.net/?s=radio

Assignment

Please send me copies of your earlier compositions. [email protected]

  • the future
  • a sound byte
  • internet API data (extra credit)
  • magical fx

Note: if you played the music in class but lost the recording, Max patch – or if it was a live performance – just let me know, in case I have forgotten. Thanks.

Here is a description of the composition for next week:

Write a composition to induce magical effects.

Here is an example from Aseem Suri http://www.aseemsuri.com/journal/piece-of-mind-second-run-at-the-csound-conference

The project was derived from computer technology, but the overall effect was that people would go into a mysterious room, for a minute, and when they emerged, they would be smiling and happy.

Due on December 15th (last class)

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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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ep-413 DSP week 6

Convolution and Voices

 

Convolution

part 1 – The time domain:

(The frequency domain):

The impulse response

  • Decomposition
  • Unit impulse (delta function)
  • convolution (from the input side and output side)
  • filters

From the output side:

Screen Shot 2014-10-05 at 3.01.04 PM

The convolution sum:

Reference: http://www.dspguide.com “The Scientist and Engineer’s Guide to DSP”, By Steven Smith – chapters 6-7
Common impulse responses:
F_7_1.gif

A ‘block diagram’ of a high pass filter. The impulse response of  low pass filter is subtracted from the impulse response of an all pass filter. Note that the all pass filter is the ‘delta response’:

Applications

Voices

Examples

Questions

 

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ep-413 DSP – week 4

Notes:

Audio Signal Processing Course: https://www.coursera.org/course/audio

By Xavier Serra and Julius O. Smith

This is a free course offered by Stanford. It starts at the beginning of October. I will be taking the course and would be happy to help you if you are interested in taking it too.

Pd weekend 2014: Katja Vetter Microphone design: http://libguides.lib.siu.edu/puredata

Part I – Pitch detection

How would you construct an ‘Autotune’ effect that works in real time?  The first requirement is accurate pitch detection:

Frequency domain:

FFT and STFT: Find frequencies where the signal has greatest energy. Tradeoff between frequency and temporal resolution. Moderate latency.

Max examples: https://reactivemusic.net/?p=11202

Also look at the builtin Max tutorials on the fft~ and pfft~ objects

3rd party Max/Pd objects:

DSP code

Time domain:

Zero crossing: Measure the period of waves by counting rate of zero crossings. Doesn’t work with complex waveforms.

Max objects: fzero~ and zerox~

Autocorrelation: Compare a signal with a time shifted copy of itself.  Low latency but CPU intensive. Can be improved by using lower sample rates and other tweaks. (Helmholtz)

Example patches: https://reactivemusic.net/?p=17169

(note: gbr.yin~ is a 3rd party object from IRCAM, but is built into Max)

Pd examples from Katja Vetter: (helmholtz~ external)

We also looked at Katja’s new app: InstantDecomposer. If you would like to try this patch, please contact me. I will need to get permission from Katja.

Wavelet transform:
Other methods:
  • phase locked loop
  • human pitch matching (what is the latency?)
  • Neural networks?
  • Statistical methods (pattern matching)?

Part II – Prototyping

Muse development case study: https://reactivemusic.net/?p=16187

Assignment

Next week we will listen to your music from the future.

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ep-413 DSP – week 2

Ways to approach a project:

Make machines that make art

Twitter streaming example:

 

 

https://reactivemusic.net/?p=5786

Infinite Jukebox by Paul Lamere at The Echo Nest

http://labs.echonest.com/Uploader/index.html

Reverse engineering

Designing Sound

By Andy Farnell http://aspress.co.uk/sd/index.php

automax https://github.com/tkzic/automax

Use the wrong tools

Ok-Go https://reactivemusic.net/?p=7971

Luke Dubois: http://lukedubois.com

Abstraction and destruction

Picasso: http://www.slideshare.net/sotos1/pablo-picasso-bulls-111

pablo-picasso-bulls-111-11-638

David Tinapple: https://reactivemusic.net/?p=7537

Do something backwards, extreme or opposite

Connect two things

Orange Plantation Lego

From an Interview of Mike Will At Bloomberg Business Week by Devin Leonard

http://www.businessweek.com/articles/2014-08-07/mike-will-made-it-hip-hops-hottest-producer-is-crossover-king#p1

“(Mike) WiLL didn’t know Cyrus, but (Peter) Edge did. She was signed to RCA. WiLL talked her into recording We Can’t Stop, coaching her through it. “I was like, ‘Yo, use that country twang,’ ” WiLL recalls. “ ‘I hear it, but you are trying to hide it.’ So she started using her country twang. That made it all-the-way dope.”

 Processing sound with pictures in Max/MSP by Tadej Droljc:

https://reactivemusic.net/?p=16887

(basic_patch.maxpat)

I’m thinking of something: http://imthinkingofsomething.com

auctioneer: https://reactivemusic.net/?p=7140

politician: http://digg.com/video/guitarist-plays-along-to-sobbing-japanese-politician

 Ask questions

Google: http://google.com

Assignment:

Go to the future. Make music. Bring it back to the present.

It should be a very short piece or an excerpt. Less than two minutes. It can be a remix of a song that you believe represents a future direction in music. Near future or distant future – your choice. Use any tools to create the music.

The result: audio or a live performance in class

Due: in class on Sept. 29