listen with good headphones and enjoy!
"the feed-back tube is a self -build musical instrument.
It consists of a long closed tube (diameter approx. 10cm, 5 meter long) with a microphone on one end and a small loudspeaker on the other. Through an external amplifier and a compressor in between I am feed-backing the internal microphone signal. Some holes and keys are placed on the tube, in order to change the resonating frequency of the air column. The internal loudspeaker is used to modulate the generated feed-back, using very soft sinusoidal tones."