Alright, I have my idea. Since I've never made a game before, I have no idea how ambitious this is :P
You are an extraterrestrial that comes to Earth for the first time. The simplicity of human ears surprises you, because you can control your ears. While humans can only hear sounds between 20 Hz and 20 kHz, you can tune your ears to hear lower or higher frequencies. Also, you can adjust your overall sensitivity to pick up quiet sounds or focus on only the loudest sounds. These abilities enable you to hear harmonies where humans hear nothing, so you decide to explore Earth and see how many things you can find that harmonize with each other.
I'm going to make it as a web app: SVG + Web Audio API + Vue.js
Would love to talk about it! I'll post a link once I get started, and hopefully can have a working version in a few hours.