Lately I’ve been experimenting with iPod Touch applications for recording sound. Generally it’s necessary to use a headset to make a recording, but my goal is to figure out a practical way to bypass the headset with an input for a high quality microphone. While unsuccessfully testing my Audio Technica AT822 stereo mic as an input for the iPod Touch I captured an interesting glitch within the application I was testing.
The low frequency waveform (shown in the image at the left) played at regular intervals while I had the microphone attached. Perhaps it’s some sort of communication protocol for headset controls. I removed the DC offset, but otherwise left it as it was. Perhaps I’ll try playing it back at some higher frequencies to see it’s useful for anything musically.
iPod Touch Glitch
After upgrading my G4 to Safari 4.0.2 today, my M-Audio 2496 PCI bus internal sound card started making this horrible sound anytime audio was played on it. My first instinct was to capture the sound so I plugged a cable into my laptop and grabbed a few seconds of it in Audacity. Listen at your own risk. It’s loud and unpleasant, but somehow fun and delightful (reminding me of someone I once dated in the past). Fortunately after reinstalling the drivers it started behaving properly again (unfortunately this technique doesn’t work on partners). 
It’s been a while since I have gone crazy applying layers and layers of mad processing to a chunk of sound just to hear what happens, but tonight I was demonstrating signal processing to my audio production class, which gave me an excuse to let loose and over process something into oblivion. I started with a one bar loop that I ripped to a .wav using iTunes, then applied reverse and pitch shifting with and without time correction. I topped it off with reverb and delay to meet the requirements of the exercise.