play_noise — a drum kit with zero samples

Port of krom (Peter Lemon)'s PlayNoise demo. The S-DSP has a built-in white-noise generator: set a voice's NON flag and the voice plays noise instead of BRR data. Every drum in the looping bar — kick, closed hi-hat, open hi-hat, snare — is nothing but three register writes: the noise clock (FLG bits 0-4: low = rumble, high = hiss), an ADSR envelope (fast one-shot = closed hat, long release = open hat), and a bare KON. A single-tap FIR echo gives the kit its room. The example ships zero bytes of sample data.

ROM mode: LoROM (project default).

Measured against the original (luna --audio-out, 40 s captures): onset gap patterns identical to 0.01 s, per-hit spectral centroids within 2 %, RMS within 1 %.

SNES Concepts

• The S-DSP noise source (NON, FLG noise clock) as an instrument
• ADSR envelope design: the envelope is the drum type
• FIR echo configuration (ESA/EDL/EFB/FIR0) and clearing the echo buffer RAM before enabling writes
• Raw APU programming via the apu module (IPL upload from C)

How to Build

make

Modules Used

console, apu