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
I don’t have this patch ready to share yet, but I thought I could at least explain a little bit about it and offer an audio example. What I’m working on is a device to manipulate samples in unconventional ways using alternative input methods. This audio clip, for example, was generated using a Max patch that adjusts the playback frequency and length of a sample using an x-y controller. The x-axis controls the frequency while the y-axis controls the sample length. For a controller I used an iPod Touch running 
One of my recent class assignments led me to create a patch that automates the playback of a pair of microtonal tones with a frequency range of 200Hz to 1200Hz. I call it the Beep Master 9000 (press tongue firmly against cheek). The large toggles in the upper left turn on and off each of the sine waves individually. The large bangs to the right randomize the frequency when clicked. Below the bangs are a couple of smaller toggles that turn on metronomes that automate the randomization of the frequency for each cycle~ object. The number boxes allow the user to adjust how often the pitches are randomized in milliseconds. The encapsulated sub-patch (“p rightMetro” amd “p leftMetro”) multiplies the frequency of each metro by 0.25, 0.50, 0.75, or 1 randomly. This causes the beats to change by divisions (i.e. 4 times faster when multiplied by 0.25, twice as fast by 0.50, and so on). Here’s a sequence I created using the Beep Master 9000.