I finally made a dock connector for my third generation iPod that I’ve been making experimental recordings on with Linux and an AT822 stereo mic. Prior to making the dock connector I was only able to make mono recordings via the headphone jack. Since the dock connector only accepts a line level signal, I am pre-amping the AT822 with my ailing Sony PCM-M1 DAT recorder (it eats tapes, so it’s a useful retirement).
With this setup I am able to use the otherwise useless DAT recorder by connecting the stereo mic to the mic input, putting the device in record mode, adjusting the levels, and then taking the line out to the dock connector on the iPod as shown in the photograph. The recordings are relatively clean except for a tiny bit of high frequency interference that I haven’t tracked down yet.
The only other problem is that recording in stereo seems to tax the resources of the iPod. When I try to record at a sampling rate higher than 44.1kHz the audio is likely to suffer from a bizarre digital jitter effect. Here’s an example of a piano recording at 88kHz that I played and edited together to illustrate the jitter problem. I wouldn’t use this rate for anything I want to record well, but I kind of like the stuttering sound it creates as the iPod fails to process the audio quickly enough to store it accurately.
iPod Garbled Piano Recording