# techno-gen

Generates infinite procedural techno music as raw float32 stereo audio on stdout.
138 BPM. No samples — everything is synthesized from scratch.

## Build

```sh
make
```

Or manually:

```sh
gcc -O2 -Wall -lm -o techno-gen techno-gen.c
```

## Play

Pipe directly into `paplay` (PulseAudio):

```sh
./techno-gen | paplay --format=float32le --rate=44100 --channels=2
```

> **Note:** `paplay` is part of the `pulseaudio-utils` package.
> On Debian/Ubuntu: `sudo apt install pulseaudio-utils`

### Mono version (if you only want 1 channel)

The program outputs stereo (2 channels). If you want mono, mix down with sox:

```sh
./techno-gen | sox -t raw -r 44100 -e float -b 32 -c 2 - -t raw -r 44100 -e float -b 32 -c 1 - | paplay --format=float32le --rate=44100 --channels=1
```

### Record to file

```sh
./techno-gen | sox -t raw -r 44100 -e float -b 32 -c 2 - output.wav trim 0 120
```

This records 2 minutes (`trim 0 120`) to `output.wav`.

## What it sounds like

| Time          | Section                                            |
|---------------|----------------------------------------------------|
| 0–3 bars      | **Intro** — kick + bass, filter closed             |
| 4–7 bars      | **Rise** — hi-hats join, filter opens              |
| 8–15 bars     | **Full** — snare, acid lead, LFO filter sweeps     |
| 16–19 bars    | **Breakdown** — bass only, stripped down           |
| 20–23 bars    | **Build** — kick returns, filter climbs            |
| 24–31 bars    | **Heavy** — syncopated kick, acid variation 2      |
| *then loops*  | Back to bar 8 (never the sparse intro again)       |

The cycle is 32 bars (~1 min 23 sec at 138 BPM), then repeats with continuous filter and pattern variation.

## Synthesis

All audio is synthesized in real time:

- **Kick** — sine oscillator with pitch envelope (200 → 45 Hz), amp decay, transient click
- **Snare** — high-pass filtered noise blended with a 185 Hz tone
- **Hi-hat** — noise through a 7 kHz high-pass; open/closed variants with different decay times
- **Bass** — sawtooth oscillator through a resonant (Q=4.5) biquad low-pass with per-note filter envelope and glide
- **Acid lead** — dual slightly-detuned sawtooth through a very resonant (Q=6) low-pass; filter sweeps with LFO per section
- **Stereo width** — short delay line (~11 ms) ping-ponged between channels on hats and acid
- **Master** — `tanh` soft saturation to keep levels honest