Month: September 2014

ep-413 DSP week 5


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.

Pitch tracking in Max

Two methods, In the time domain.

Counting zero crossings, in the time domain, to measure the period and frequency of a sine wave, using zerox~ and edge~

A patch by Mari Kimura that compares the Max fzero~ object with the IRCAM gbr.yin~ object – measuring frequency in the time domain. gbr.yin~ uses autocorrelation.

Note: gbr.yin~ is part of the FTM package. Download and install from here:


folder: pitch-tracking


  • zerox-test.maxpat
  • MKtest-pitchtrack.maxpat


ep-413 DSP – week 4


Audio Signal Processing Course:

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:

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:

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:

(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:


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

ep-413 DSP – week 3

Composition tools

Make music using X

“Lyrebirds and Acoustic Guitar” by Chris Lopez

Tools used by students in this class:
  • Reverse engineering the style of a reference song. Use a Midi keyboard + Logic
  • Maschine + microphone
  • Modular synth + Midi
  • Listening to melodies in your head + Ableton Live
  • Building a chord progression, playing piano, guitar, Ableton Live racks
  • Composing with drums in Ableton Live. Building a form or structure. Using the ideas in your head.
  • Ableton Live.  And playing the guitar.
  • Finale music notation software.
Dramatic shape:

Every performance has a dramatic shape. That is, excitement level measured over time.

What is the shape of this piece:


Like stories, songs have beginnings, endings, and journeys that connect.  Many forms can be applied, but the goal is always the same – to have maximum impact on the listener – to communicate honestly with strength and conviction.

As you listen to music, be aware of the form – especially in terms of the dramatic shape.  Where is the peak of intensity?  Does the music grab your attention immediately, or does it build slowly?    How much repetition do you hear?  Can you find suspense, surprise, humor, sadness, power, or beauty?  What musical elements work together to create these feelings?

The most powerful tools you have as a composer are your ears.

ep-413 DSP – week 2

Ways to approach a project:

Make machines that make art

Twitter streaming example:

Infinite Jukebox by Paul Lamere at The Echo Nest

Reverse engineering

Designing Sound

By Andy Farnell


Use the wrong tools


Luke Dubois:

Abstraction and destruction



David Tinapple:

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

“(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:


I’m thinking of something:



 Ask questions



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