I have begun to refine the patch I described in the last entry, creating an instrument that allows you to traverse through samples using an x-y controller and a slider. The x axis controls the forward or backward playback frequency of the grain. The y axis controls the width of the grain; either very narrow (minimum of 10ms), to an adjustable percentage of the sample at the widest (15% by default). The slider controls the position of the grain in the sample. Buttons across the top allow you to choose one of five preset samples. Alternatives can be loaded in the patch or set as defaults.

So far the TouchOSC controller is working quite well for the project. It was a bit tricky getting the interface to reflect changes in the patch, since radio button behavior is not supported in TouchOSC. Fortunately it supports an input port, so I managed to get all the buttons toggled properly by sending data back to the iPod Touch. I have connected the accelerometer to a filter so that when turned on with a toggle, tilting it on the y axis causes a lowpass filter to effect the output. Finally, by setting a threshold on the z axis, giving the iPod Touch a brisk shake will cause the patch to loop a randomly selected grain of random length from a randomly selected buffer played back at a randomly selected rate. The variety of sounds possible with five short samples is huge. Here’s a selection of sound produced with one sample selected. The sound source is from a vintage video game. I’m curious to see if anyone can recognize it. Please post your guess in a comment.

Etude in 8 Bits for Multitouch Graintable Synthesis