mecca

MECCA Music Platform

The Music Education, Composition, Creation Application

MECCA is a live music coding environment for Clojure code inspired by Mario Paint.

It was originally meant to be a chiptune tracker that would simply emulate the 4 channels of the NES. But then I started playing around with alternative interfaces and while working on an SVG music notation rendering engine I realized that my priorities were definitely out of whack, and what my program really needed was a jumping Mario and animal noises.

I found that the specific subset of musical features used in the Mario Paint music maker provides a delightful scope of creative possibilities while remaining very approachable. And by using distinctively styled note heads that play samples of a common length, a whole set of elements to implement goes away, like rests, stems, beams, and the need for multiple staves for each voice. Besides providing a more quickly acheivable development path, this choice burdens a new music student with less advanced music theory from the start, making for a more compact interface where the composition can be tracked without any mental context switching.

Check out the inspiring paper Mario Paint: An Accessible Environment of Musical Creativity and Sound Exploration.

Try it live

I ended up getting a bit carried away with the pixel art, after trying every SVG tool I could find I was still unsatisfied with the results, so ended up coding it all by hand as basic lines, shapes and paths. For example, the castle in the picture above is actually a function that outputs staggered rows of dashed lines representing bricks and mortar organized in a stretcher bond masonry pattern. And that Mario is not even a sprite - he’s a group of vector paths connected to form his limbs, hat and moustache. And once this app blows up and I get sued by Nintendo, a new version will be out with a character called Mr. Moustache, who will in fact be nothing more than a bouncing moustache on a stick with a red hat on.

Future ideas

It would be cool to be able to record, link or upload your own samples. However, when Koji Kondo said that composing for the SNES is 1000 times harder than composing for the NES^{[citation needed - discuss]}, he was warning us about the choose-a-phone problem. Being sample based, the SNES can play any sound you throw at it, while the NES only plays one set of built-in sounds. See, once you have no idea what instrument you are composing for, all bets are off. The nature of art is defined at least in part by the limitations of the medium.

As Rich Hickey said, “no one wants to compose for a choose-a-phone ensemble”.

See the paper, Game Scoring: Towards a Broader Theory for a fantastic treatment of the specific musical inventions that came about through creatively overcoming the technological limitations historically involved in the development of game music.

So how can we expand the sonic palette without turning it into a choose-a-phone?

This question goes right to the heart of a creative platform’s design philosophy, and mine is something like (to put it in one line): “to subtly encourage the use of effective idioms while maintaining maximal expressivity.”

One idea is to make an 8-bit / 16-bit switch that will transform the whole UI respectively from synth oscillator to sample mode.

For the synths, I believe that by using the very efficient algorithms from Blargg’s blip-buf library, a full emulation can be done in the browser quite easily. Since the NES APU produces sound via a sample/hold circuit, it is only necessary to generate the ends of the waveforms (the transitions) since the middle part is the same regardless of frequency, differing only in length.

• Noise channel produces pseudo-random bits by linear feedback shift register method. This is then played back at 16 possible sample rates to produce hihats, snares and other percussive sounds. A much shorter bit sequence is also possible, which is perceived by the human cognitive auditory system as a metallic tone rather than noise due to its periodicity.

• The triangle channel (for bass and kick drums/toms) is actually a 16 step quantized triangle-ish wave with a slight shark fin shape that also has tiny sawteeth on it. Gotta get this stuff right. That’s what gives the Nintendo basslines those really sweet whirling harmonic overtones. The waveform is actually produced by hijacking the channel’s velocity control on the chip and using it as a 16-step counter. For this reason the bass channel has no adjustable velocity, notes are either on or off.

• The 2 pulse-wave (lead) channels offer a variable duty cycle, so the standard Web Audio square wave will also not do here. However, we do have the option of using a wavetable, which can produce an arbitrary periodic waveform defined by a list of sin/cosine terms for the Fourier coefficients, which can be easily derived for any sound by playing it through the FFT provided by the Web Audio analyzer node EDIT: it seems we will need a separate FFT library for this (or write one) because, quite annoyingly, the analyzer node’s FFT doesn’t provide the sine/cosine values, only the frequencies…

• Linear-interpolated bandlimiting will be good enough, since we have the ability to use the hardware clock exposed by the Web Audio API to oversample at an extremely high rate, supressing aliasing far below perceptible limits.

Development

Do the thing:

$ npm install
added 97 packages from 106 contributors in 5.984s

Start the development process by running:

$ npx shadow-cljs watch app
...
[:app] Build completed. (134 files, 35 compiled, 0 warnings, 5.80s)

Or simply jack-in from your editor if you use CIDER/Emacs/Calva, etc. Your app will be served at: at http://localhost:3000.

Production build

npx shadow-cljs release app

Thanks to Bruce Hauman, Chris Ford and Dave Yarwood for blazing the CLJS Web Audio trail. No way could I have figured this all out myself.

Funding

My greatest passion is making music with code, and I believe that there is a vital connection between these domains that is being missed in our educational culture. When the execution of a program results in a richer sensory experience, it facilitates an intuitive understanding of algorithms by engaging the student in a more tangible feedback loop. By teaching these disciplines together, it can unlock an appreciation and continued interest in each of them, and may result in more people building stuff we never thought possible! Sponsor me on Patreon to help me build software for music education.