A lot of the ITC work I do, I try to keep it all electronic. I like to use microphone amps, analog-to-digital converters (ADCs), software defined radios (SDRs), and field-programmable gate arrays (FPGAs). However, I have explored a few mechanical noises sources in the past including dragging a microphone across a wood table and some plastic crumpling (following Andres Ramos' efforts).
Let's just say I was recently inspired by the heavens to look at mechanic vibrations again. Also, some of my Here colleagues are exploring mechanical ITC too, so I thought I'd give it a try. Where to start? Well I know that spirits can form voices in air, and we can pick them up microphones, but as expected, the voices come out "wispy." If you think about them as exciting tones within the air, the tones aren't going to last very long with the way air is. Meanwhile, we know that metal has a very long "ring" or slow dampening coefficient.
However, metal is heavy and it needs to be "excited" or struck to make a sound. In regular air, it should be just about silent, although I'm sure a very sensitive microphone could pick out the thermal vibrations of a metal guitar string. Therefore, I needed some form of excitation. One idea would be to periodically tap the strings of guitar and then listen to the slowly declining ring of tones. Another possibility is to blow a fan at the strings. Another is to use the vibration of the fan itself as an exciter.
The positives of the fan include (1) simple to do, (2) somewhat random, possibly evenly distributed excitations. The negatives include 1) the fan's electrical interference to the guitar pickups and 2) The random and periodic signals of the fan itself which may or may not be perturbed by spirit.
Here's the apparatus:
Here is the best clean "excited" guitar string sound I could get today:
Unfortunately, I can't reproduce this now, so I'll have to endure a higher proportion of electrical noise.
Here are some machine-learning-translated words or phrases. There are not the best I've observed, but fun nonetheless.
"that is beautiful"
"yes all the runs are beautiful"