I’ve recently been really interested in microphones and how they are meant to amplify very specific things. For example, contact mics are meant for capturing the sound of something interacting with the mic. It doesn’t have the best sound quality and is inexpensive because it is supposed to capture generality.
Although ultrasonic microphones have some of the highest sample rates of most microphones, they aren’t necessarily the best microphones for music production or for radio broadcasters as an example. Depending on the purpose of the microphone, they are biased towards various portions of the frequency spectrum against others, and I find the technology that allows this to happen to be very compelling.
My idea is to mic a long list of things, and create a library of sounds that are constantly being recorded, but aren’t heard in the average human frequency spectrum. I plan to record sounds, places, people, and everyday interactions at the highest sample rate the ultrasonic microphone In order to avoid aliasing, there will be an initial hard bandpass filter that filters out everything beyond 192khz. After, I will filter out the audible information from 0 to 20khz. Then I will tune everything up into 192khz frequencies down several octaves until all of the information that was inaudible is audible and the initially audible portion of the frequency spectrum is no longer audible.