The Smallest Sample on ACB

This tiny sample of audio represents the instant that my iPod ran out of battery life while recording a performance of myself, Nils Westdal and Graham O’Brien on drums from Monday, November 17, 2008 at Cafe Barbette in Minneapolis.

Typically when a recording is interrupted due to power loss on a digital recorder, the device is unable to save the document properly so what you end up with is a corrupt file, or worse, nothing at all. In my case I ended up with a corrupt file on the iPod of about forty five minutes of our second set. After a minute or two of searching I discovered that Audacity has a file menu option called “Import Raw”. Using this option I was able to import the unreadable content into Audacity.

I was delighted to see that most of the recording was intact. However, what was was interesting to me is that at the end of the file was about a minute or more of random white noise. I fancifully imagined this as my iPod going into a dream state as the power level was no longer adequate to support the standard functionality of the device. So here’s the first 48 milliseconds of that dream state with a three dB pad to eliminate clipping.

Ghost in the Machine

Insectoid X-19

This afternoon I stumbled upon another one of my recent FM synthesis experiments from November 2, 2008. On that day I recorded eight minutes of output from select randomized programs that I produced using a MaxMSP patch called X.FM. You can hear all of the examples I have posted so far by clicking on the FM Synthesis topic.

This eighth example in the series has some nice rhythmic, pulsating characteristics to it. I edited the sound out from the surrounding audio, then exported it with normalization to boost the levels.

Insectoid X-19

 

Portable Digital Recorder Resources

After several weeks of research I have finally made a decision and purchased a Sony PCM-D50 digital recorder (without the fancy leather carrying case) to replace my mostly broken Sony PCM-M1 portable DAT.

During my research I came across some excellent resources that helped me make up my mind. I found some of the most thorough information on O’Reilly Digital Media. Their comparison chart was invaluable along with the extensive reviews of all the devices listed there. I consulted other in-depth reviews and another great comparison chart at Transom.org. I also read many of Brad Linder’s reviews including his review of the PCM-D50 and Create Digital Music pointed me to more reviews of just about everything I looked into.

This is by no means a complete list. I read lots of other articles and websites along the way, but these sites certainly helped the process along. I have yet to receive my new toy, but as soon as I do I’ll be posting some first impressions and sample recordings.

Mangled, Reversed, Distant and Filtered Piano

Over processing usually leaves you with audio that lacks it original luster, or perhaps it starts to sound like the processor itself. However, sometimes you might end up with something interesting as a result of pushing the processing beyond the normal boundaries. While listening to the garbled piano in the last entry I could hear something haunting about the passage, so I decided that I would try to bring out those haunting characteristics by adding some unrestrained processing to the recording. I started by reversing it and pitching it down a couple of semitones. This brought out a brief harmonic minor melody. Later, after applying some extreme filtering and massive reverb I ended up with this thin, distant, and haunting sequence.

Mangled, Reversed, Distant, and Filtered Piano

iPod Garbled Piano Recording

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