Category Archives: GMS

The GMS (Gestural Music Sequencer), written in Processing.org by Unearthed Music recording artist and AudioCookbook.org founder John Keston, analyzes video input and converts it into a sequence of musical information in real-time. Each frame is processed to find the brightest pixel. The x coordinate is converted into pitch while the y coordinate is translated into dynamics. The application was also designed to use probability distributions on pitch and durations.

GMS Audio Captured During MAW Outing

Posted on April 30, 2009 by John Keston

This eight minute segment of audio generated by the GMS is from the first eight minutes of our most recent MAW (minneapolisartonwheels.org) outing.

This was my first chance to take advantage of the presets feature, but the performance led me to expand the octave setting to include adjustments for the top and bottom octaves. During this performance the octave setting was limited to only allowing the top octave to be lowered. This made it so that instruments with a limited range, like drums, are difficult to play since much of the screen might be inactive.

MAW Outing Segment

Presets Feature Added to the GMS

Posted on April 29, 2009 by John Keston

The latest feature I have added to the GMS is a way to store ten presets. Each preset holds thirty-four distinct settings including all twelve note probability values, all seven duration probability values, note probabilities on/off, duration probabilities on/off, sustain on/off, free time mode vs bpm, dotted notes on/off, video mirroring on/off, tempo in BPM, note durations, transposition, scale, MIDI out channel, dotted note probabilities, note randomness, and octave range minimum and maximum. The presets can be changed by clicking a radio button, or pressing control plus the preset number. This feature makes it possible to instantly and dramatically change the behavior of the GMS. I also added a primitive save and load feature to mantain the content of the presets. Here’s a segment from a test recording.

GMS Preset Test Audio

More GMS High Speed Glitches

Posted on April 28, 2009 by John Keston

As I spend virtually every spare moment working on the GMS I’m looking forward to slowing down the development of this sequencer so I can start using it effectively, but for now I’m happy to create the odd glitch or space pad here and there. Here’s a glitchy segment of sound created by classic, channel ten drums at high speed.

GMS Drum Glitches

Electrical Crackling Sound with the GMS

Posted on April 27, 2009 by John Keston

This electrical crackling sound was made with the GMS while the tempo was set quite high and the note duration probability distributions were set to favor two adjacent values. The speed that the notes were played made the frequency of playing the notes more audible than the pitch of the individual sounds themselves. The randomized durations at that speed created a sputtering quality that, to my ear, sounds very similar to high voltage electrical sparks. Interestingly it turns out that the GMS might be useful for sound design as well as a composition and performance tool.

Electrical Sound

GMS Drum Solo

Posted on April 26, 2009 by John Keston

To create this silliness I set the GMS to play the drums on the built in Java Sound Synthesizer. I adjusted the tempo and duration probabilities to something ridiculous then captured the output on my PCM-D50. Since this experiment I have made a few more that are even more high speed and scattered. Perhaps I’ll post more examples of this nature. I have rare instances of longer durations inabled in the probability distribution, so as you’re listening, every so often you may think that it’s over (finally!) when suddenly it starts up again with obnoxiousness.

GMS Drum Solo

Sixty Fourth Notes from Twenty BPM to One Thousand and Back

Posted on April 23, 2009 by John Keston

I’ve already posted a few glitchy sounds created by the GMS in it’s various states of development. Most of them created by some bug, which I love. Serendipity never looses its charm for me. This sound is more deliberate and illustrates how sixty fourth notes sound played on a basic piano sample from twenty beats per minute all the up to nine-hundred and ninety-nine BPM. I’m not sure how accurately the GMS is reproducing these durations at tempos greater than five-hundred beats per minutes, but it sounds pretty wicked anyway.

From 20bpm to 999bpm and Back

External Sync Feature Added to the GMS

Posted on April 21, 2009 by John Keston

With some expert help from Grant Muller I have successfully added the capability of synchronization with an external MIDI signal to the GMS. This feature opens up vast possibilities for performance and collaboration with the tool. To test the feature I sent external sync from Ableton Live to the GMS, which in turn routed note information back through the IAC drivers into Ableton to drive a VST FM synth. I started by live looping a few phrases from the sequencer including a bass line, mid-range arpeggio, and some heavily delayed FM clav, then put it together with a recycled beat into a two minute micro-track. Everything heard, except the drums, are notes output from the GMS via video stimulus.

GMS External Sync Test

Chromatic Currents Part II

Posted on April 20, 2009 by John Keston

This second part to “Chromatic Currents” was produced with the GMS by using a string of lights placed into a large glass vase. I moved the camera around the vase to direct the flow of musical phrases with one hand while I adjusted transposition and note duration settings in the sequencer with my right.

You might notice that the video stimulus does not resemble lights in a vase. This is because I applied a negative filter to the video after capturing the performance. Once again I used a pleasant pentatonic scale interspersed with rare dissonant notes and probability distributions in the note durations to give it an eerie awkwardness.

GMS: Chromatic Currents Part II from Unearthed Music on Vimeo.

Chromatic Currents Part I

Posted on April 19, 2009 by John Keston

Here’s a segment of sound from another GMS video I produced yesterday called Chromatic Currents. Once again I was letting the visuals drive the piece, while I controlled parameters in the GMS. On Sound Globules I used the circle of fourths with probability distributions so that C was the most frequent note followed by F, Bb, Eb and so on. I really liked the rare dissonant pitch making its way into the sequence, so I tried a similar technique for Chromatic Currents. The scale was strongly C minor pentatonic, weighted with the Dorian mode by adding less-likely probabilities for D and A. However, every note that was not part of the scale still had a small possibility of occurring. This led to occasional blue or dissonant pitches in the stream of notes. The possibility of having any note within a chromatic scale occur in the stream led me to the title.

Chromatic Currents

GMS Videos and Interface

Posted on April 18, 2009 by John Keston

Today I made two more videos with the GMS using a different technique than in Dodger of Red Lights. This time I wanted to explore what could be produced using visual input that I wasn’t directly controlling. The obvious, albeit cheesy, lava lamp came to mind, so I turned it on and went to work.

I connected a separate video camera via firewire, leaving a screen with all my interface controls available for me to tweak while recording. I recorded the video to MiniDV on the external camera, and as before recorded the output onto my PCM-D50 to free up the CPU for Reason and the GMS. Since I was recording the video on the external camera I had to the flip the video so that the image corresponded properly with the sound. This led me add a feature for toggling the mirroring in the GMS.

Click the image to see a full sized screen shot of the interface. All three videos are available on the Unearthed Music Vimeo account. Here’s an excerpt of audio from the piece titled Sound Globules.

GMS: Sound Globules