The worlds of computers and electronic music go hand in hand, and often there are unexpected oddities to be found, marrying the two. This Audio Spectrum Analyzer for the TRS-80 Color Computer (Radio Shack Cat. No. 26-3156) is a surprisingly responsive and well-featured example, released way back in 1981 by Steve Bjork (possibly no relation to the singer). The Tandy Colour Computer (or CoCo) uses a Motorola 6809 processor which is clearly capable of doing FFT (Fast Fourier Transform) pretty accurately using the TV RF connection. Here's a bit more information from the video:
Reddit user CheapScotch confirmed that this is 100% software based. People had produced both a tape and disk version of this software which you can find online. He tried one of these on his Coco 2 and it worked perfectly. (It is just a 4K ROM.) This shows that there is absolutely nothing in the cartridge other than a ROM and the Coco is able to do all of this using built in 1980 technology.
The video is made by Adrian's Digital Basement https://www.youtube.com/channel/UCE5dIscvDxrb7CD5uiJJOiw