Great sound, thanks! I'm using it in an alien landing soundscape to start my radio show tonight, doing a Halloween special. Here's the blog entry where I put all the Freesound attributions, and tell you where and when you can listen. http://www.theglobalvoice.info/blog/?p=645 After first airing, it will only remain in the Gallery for one week before replaced by the next week's show, so let me know if you didn't get it.
This Sound was created on my homebrew sythesizer. Using a sinusoidal signal, passing it trough several notchfilters and at the end it was pushed into a bucket brigade store. The synth is a hybridsynth using analog and digital circuits.