Roll Your Own Binaural Microphone

First of all, thanks to Leafcutter John for encouraging me to look into binaural recording. As a result I spent most of last Sunday designing and building a set of binaural microphones. What’s surprising is that I had everything I needed in my home. I started with a couple of old Mac computer mics that my friend Kevin gave me a few weeks ago. I tore them apart and removed the electret capsules from the circuit boards. I found a set of silicone ear-buds from an old mobile phone headset that fit the capsules perfectly. After that it was pretty easy.

On my first attempt I used the cabling from an old set of airline headphones, but the stiff wire going from the right to the left microphone was too sensitive to vibrations. After all that work I decided to disassemble it and start again. This time I sacrificed an old pair of JVC headphones. The cabling was much better and had separate cables to each driver. This time I used a paper hole punch to modify the ear-buds so the back of the capsules weren’t stuck in a vacuum. I used colored heat shrink to specify left and right, added a tiny bit of foam between the capsule and the ear-bud, then mounted a couple of layers of foam over the outside.

I was pleasantly surprised by the few test recordings I made. For the majority of the tests I placed the ear-buds into my ears and kept as still as possible since the mics are quite sensitive while plugged into the Sony PCM-D50. I ended up using the 20dB pad, although I got a better sound without the low cutoff filter enabled. For some other examples visit this post on Leafcutter John’s blog.

Binaural Finger Snaps

Summer Glau Triple Mash and Cooked by Teru

While browsing ccMixter recently I came across this track called Summer Glau by John Anealio remixed by Teru that incorporates sounds from ACB including Pro-One Dub and apparently Synthesizer Fifths Drone although I couldn’t make it out in the mix. In any case, after a bit more browsing I came across another Teru mix called Cooked (mega downtempo) that uses Synthesizer Fifths Drone, Rhodes Wah Wah, Electric Razor, and Door Stop all sounds I posted on AudioCookbook.org. I must admit that it is fun to come across examples of ACB samples being used by other artists. I’ve linked the tracks below, or visit Teru’s page on ccMixter to hear what else he has on offer. You can also checkout the Audio Cookbook Sample Pool to hear how other artists are using ACB samples.

Cooked

Summer Glau Triple Mash
(vocal mix)
Summer Glau Triple Mash
(instrumental mix)

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.

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

One Hundred Sounds in Eight Seconds

Last Friday, November 7th, to mark my one hundredth sound posted in the One Sound Every Day category, I sequenced forty two equally sized micro samples extracted from sounds I had posted here on AudioCookbook.org. Due to a trip scheduled out of the country, I ran out of time and did not compile all of the available ninety nine sounds into the piece. As promised in the original post, I have now managed to complete the chronologically sequenced compilation of micro samples into eight seconds of chaotic noise. I extended the one hundredth sample of Caribbean surf as an ending to the staccato sequence.

100 Micro Samples