2048b FM

Less bytes?

Smaller version of this is 1kilobyte, can be found here: khoin/1kfm

What is this?

This is a FM (PM) synthesizer that runs in your web browser. Its file size is 2048bytes (index.html). You can check out the commented source in uncompressed.html.

Features

• 6 Operators
• ADS (Attack, Decay, Sustain) Envelope
• Theoretical 32-voice polyphony (on my computer, no keyboard events fired after holding down 6 keys)
• Arbitrary operator routing. Any operators can route to any other operators, even self. They can be carriers and/or modulators.
• Saving and loading patches
• C4-A5 keyboard (corresponding to 2 top rows on your keyboard, Q to backslash).

Components

• Bitmap font 0-9ADSICTO at 160 bytes + 59 bytes (for pixel drawing)
• Bresenham line drawing at 159 bytes + 59 bytes (for pixel drawing)
• DSP + keyboard mapping is at 668 bytes
• The rest: GUI, mouse, patch save/load 754 bytes

Caveats

• It is not possible for modulators (that does not go directly to output) to be silent. I did this so that we can skip calculations if an operator have zero volume.
• No release envelope stage :c
• No fixed frequency mode.
• It is not a DX7 emulator :c I first wanted it to be one.
• On my machine, if you don't have any modulation, it doesn't lag. But if you do, it usually lags out at 3-4 voices. On my machine, it appears that Firefox's script processor isn't as fast.
• <meta charset=utf8> was added so the GUI would render correctly in Firefox and Edge.

Diagram of parameters

This part assumes you know synthesis concepts. Here's a diagram:

Example Patches

• Glass Keys
• Saw Bass
• Chord Brass-like Synth
• Organ
• Flute (You have to turn the Tune parameter to some other value, then back to 0 again to feed the noise)

Acknowledgments

• Thanks Werner for showing me more efficient way of PM/FM synthesis
• p01 for such awesome 1k demos that got me into this.

License

Public Domain.