March 31, 2026
When your drum machine screams data
Teenage Engineering's PO-32 acoustic modem and synth implementation
Beats by beeps: Drums sent as sound—fans cheer, purists ask 'Is this just MIDI?'
TLDR: An open-source tool makes the PO-32 trade drum kits by sound and even synthesize hits, turning beeps into beats. The community is split between “this is genius,” “isn’t this just MIDI?”, and pure nostalgia for radio-era screeches, with hackers itching to know how it was cracked and why it matters to tinkerers.
Teenage Engineering’s cult-favorite PO-32 just got a community-powered glow-up: an open-source C library called libpo32 that turns data into sound, plays it out like old-school dial-up, then decodes it back—plus it can synthesize drum hits from 21 tweakable settings. In plain English: your pocket drum machine can now trade beats by literally making noises at itself. The crowd went wild, but immediately split into teams. One camp, led by larme, wants to know if the custom drum sounds are accurate to the real thing. The other camp rolled in with a spicy question from kmeisthax: “Isn’t this what MIDI is for?” Cue the explainers: MIDI sends instructions, not actual sound; this trick encodes structured kit data as audio for the PO-32’s quirky format.
Nostalgia surged hard. gxd dropped a throwback to when people beamed games over FM radio, and the thread filled with jokes about cassette squeals and “my modem just dropped a beat.” Hackers circled, asking creator ericlewis how they cracked it, with socks confessing they almost tried “voltage glitching” (translation: zapping the chip to spill secrets). Meanwhile, chabes pointed out that Mutable Instruments did similar audio-based updates and linked to their dev environment. Verdict: a tiny, MIT-licensed tool sparked a giant vibe—half awe, half nerd courtroom, and 100% retro-noise fun.
Key Points
- •libpo32 is a C99 library for acoustic data transfer and drum synthesis targeting the Teenage Engineering PO-32.
- •It builds transfer frames from typed packets, renders them to mono float audio using DPSK modulation, and decodes audio back to frames.
- •The library synthesizes drum sounds from 21 patch parameters and is self-contained without external DSP libraries, platform audio APIs, or file I/O.
- •A demo verifies a lossless roundtrip and outputs demo_modem.wav and demo_kick.wav; build and tests use CMake and CTest.
- •Public APIs are defined in po32.h and po32_synth.h; the project includes docs on architecture, protocol, API, and synthesizer design, and is MIT-licensed.