Gian Pablo @ ITP

I played the Mutation Synth at the NIME/Algorithmic Composition show, at Exit Art.

It was very exciting to hear the Mutation Synth connected to a really loud sound system - I had only listened to it through headphones until then. There is a short video of me playing the synth here. Unfortunately the sound is not great, I'll be posting some samples from the synth a bit later.

I was very pleased with the instrument: a couple of last minute changes made it much more interesting to perform with. The ability to save and restore states of the system allowed for much more drama in performance. As expected, the technique of bringing back a saved state then letting it "mutate" in different directions was a good way of structuring a performance. Without this, the changes are always too gradual - it is very difficult to make dramatic transitions.

I also made another change just before the performance, which was to only allow mutations at the end of each melodic phrase. This had the effect of slowing down the mutation rate (from 400 times per second to 2!) and making the repetition of the note phrases that much more apparent.

Continue reading "Performance at NIME/Algorithmic Composition Show" »

Posted by Gian Pablo at 10:05 AM | Permalink | Comments (0) | TrackBacks (0)

I built a prototype (and probably final model...) of the case for the mutation synth.

Here it is in all its finely crafted glory:

I have a bad habit of always leaving physical construction until too late, and it always takes longer than expected. After shattering yet another sheet of acrylic, I went to the hardware store and bought a proper set of drills.

Once the physical model is built, however, testing the performance of a system becomes much faster, and more interesting. However, I tend to spend too much time testing and refining the software and electronics before really thinking about construction, let alone performance...,

What does it do?

The four toggle switches at the top control whether mutation is happening (or not happening) for four parameters of the music.

The four knobs control the intensity of mutation. Some of the parameters have a directionality. In this case, centering the pot slows mutation, moving it to either extreme expresses that valence (eg. overall pitch up or down, mood happy or sad, etc.) The parameters I'm working with now are transposition, permutation, rhythm and sound type. In effect, the pots allow you to tighten or relax the fitness equation, much like a genetic algorithm.

The two rows of four buttons allow saving and restoring the state of the synth. If you come across a mutation that sounds good, you can save it into one of four slots, and just as easily recall it.

I am trying to avoid control over individual voices - I like the model of interacting with an algorithmically generated "ensemble". I will probably end up making two of the voices "altos", two "tenors" and the last two "basso" drones. However, I might add individual cut switches for each voice.

Posted by Gian Pablo at 10:06 PM | Permalink | Comments (0) | TrackBacks (0)

In the latest iteration of my Arduino Audio project, I have now set it up to play Steve Reich's "Piano Phase" piece, inspired by ASDF;'s innovative performance of the same.

Click here for a sample

and to prove that all 6 voices are working, here's a version with 6 "pianos" all gradually drifting in and out of phase.

Click here for the 6 voice version

Posted by Gian Pablo at 07:22 PM | Permalink | Comments (0) | TrackBacks (0)

My final project for Performing Technology and Algorithmic Composition is to build a "hybrid instrument", one that will take input from a performer but also generate significant parts of the output via algorithmic means.

I want to make this instrument self-contained, so I've been working on a polyphonic sound synthesis technique using the Arduino microcontroller.

Today I implemented the "Seven Bridges of Konigsberg" assignment entirely on the Arduino.

Click here to listen to a sample of the output from the Arduino.

Click here to compare it to the Processing + Csound version.

Getting to this is an important milestone, since I have ended up building quite robust systems for scheduling and manipulating sounds using this synthesis technique.

Posted by Gian Pablo at 03:15 PM | Permalink | Comments (0) | TrackBacks (0)

I completed the meditation on the Seven Bridges of Konigsberg. Actually getting stuck into Processing and CSound was a good experience, the workflow is actually pretty reasonable once you're actually trying to do something.

The problem is to simulate a random walk across the bridges of Konigsberg, with no back-tracking (ie. never cross back on the bridge you just crossed), and then make a composition with sounds assigned to each bridge and each place.

Here is a simple diagram of the city of Konigsberg, showing the numbering scheme that I used for bridges and places.

I used a Processing app to generate a score file for Csound, and made my own basic Csound orchestra using sounds from a library that I had lying around.

I've made a pack with all the files necessary for this project, and it put it online here. That includes the Processing program source code as well as all the samples.

The output wave file from the project is here.

There's a more up-tempo version here (recommended)

I'm probably going to vary the instrument sounds going forward.

Posted by Gian Pablo at 05:11 PM | Permalink | Comments (0) | TrackBacks (0)