It's been a 7+ years solo build research and design project that is based on my own research and experiments made to explore music as an engineer and independent learner. I was a drummer when I started working on Chromatone but now I have released a number of music albums and singles as solo musician, play 2-4 live sessions a week and help others get into music in their own way.
But I'm not fanatic about the colorful notes. On the main page of web-site you can click a cog icon in the "flower" logo and then adjust any of all of 12 note colors to your preference. And this palette will be used throughout the Theory articles and Practice apps. I know that some people might have synesthesia with conflicting colors. And that those who have music in their hands already wouldn't appreciate another door to the room they're already inside of. But yeah, no matter what language you use to get into music, finally we can always close our eyes and just listen to it. The instrument stickers I make for Chromatone get smaller with the growing skill of musicians using them.
So the Chromatone web-site itself is my gift to those who would like to go the same path from wondering what are all these notes about to having a variety of instruments at hand that I can teach, explore and perform music with. And many of them are those web-apps in the Practice section.
Check out these main points of interest there:
https://chromatone.center/practice/rhythm/circle/ Very powerful polyrhythmic metronome
https://chromatone.center/practice/pitch/spectrogram/ Colorful spectrogram of incoming signal. It's showing the significance of Chromatone coloring as it's absolute and can give exact color for any given frequency and vice versa. So we can see frequencies and relations between them. You can literally see timbre as lines of harmonics present in the sound. The better the mic - the better the spectrogram resolution and quality.
https://chromatone.center/practice/chord/fifths/ Very useful interactive Circle of Fifths with MIDI support, seventh chords and 4 inversions of each available to play with. Incredibly useful instrument for composers.
https://chromatone.center/practice/chord/array/ Tonnetz diagram colored with Chromatone looks quite appealing. Choose a tonic and a scale at the panel to the left (circle with the tonic note name) it will filter out inactive notes and chords. Multitouch available.
https://chromatone.center/practice/chroma/palette/ Minimalist and efficient visualization of MIDI and analysed sound notes in a GLSL shader.
https://chromatone.center/practice/midi/monitor/ Shows all MIDI signals received in a handy table view
https://chromatone.center/practice/synth/elementary/ Main synth on the web-site is quite powerful now and has saw/square oscillators, noise oscillators, Karplus-Strong string voices, sampler voices in a polyphonic synth with some reverb and ping-pong delay added. All adjustable with the left side panel (with keyboard icon).
https://chromatone.center/practice/generative/bounce/ Generative melodies with shifted period sine waves.
https://chromatone.center/practice/jam/random/ a tool for jams - click that one button and get a random BPM and scale to jam in for the next 10 minutes or so. It's like a geolocation for a jam session.
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The project is open-source https://github.com/chromatone/chromatone.center and I'm open not only to good advice but to actual contributions to the Theory articles in Markdown and also the Practice apps code written in Vue 3, Vitepress, UnoCSS, pug and other JS ecosystem goodness. Or just give the repo a star! We're approaching v3.0 soon - it will mark the completion of ongoing cleanup of tech debt from years of early development making the site and the NPM lib (https://www.npmjs.com/package/use-chromatone) robust and usable by many new music students, explorers and performers.
AMA!