There is no faster chirping sound. I'm guessing you are using Jesvs's sox line? I was very surprised sox was able to work at all, half of the settings were wrong. Try
I've just listened to the mp3 linked from the page (http://kmkeen.com/tmp/awkbient.mp3) and I've heard the sounds I've described. I hear it like "(loud:) dong (quieter:) brrr-brrr-bbrrr (loud:) dong (quieter:) brrr-brrr-brrr (loud:) dong"
The brr-brr sounds are the unpleasant ones. I hear them also when listening to wav made by lame --decode of mp3.
awk [...] | sox -c 1 -b 8 -r 64k -e unsigned -t raw - -d
instead. No clicking/popping with that.