# Driftel

> Warm, wandering echo. Repeats bend in pitch, soften and saturate as they fade.

- Engine id: `org.sournd.delay.driftel`
- Category: Delay
- Licence: free: a closed library, free to use in your plugins, downloaded with no account or email
- Download (no account or email): https://sournd.com/download/free/macos (macOS universal), https://sournd.com/download/free/linux (Linux x86_64 and aarch64) or https://sournd.com/download/free/windows (Windows x64). One archive with every free engine: static library, C headers, README.
- Version: 1.0.0
- Latency: 0 samples
- Tail: 60 s
- Sidechain input: no
- Channels: mono or stereo
- Audio demo: https://sournd.com/static/preview/demos/driftel.mp3 (plucked chords, default settings)

## Parameters

The id is the C ABI parameter id and the JUCE parameter id (as a decimal string).

| Id | Key | Name | Min | Max | Default | Unit | Taper |
|---|---|---|---|---|---|---|---|
| 0 | `time_ms` | Time | 20 | 1000 | 340 | ms | log |
| 1 | `feedback` | Feedback | 0 | 0.98 | 0.45 | - | linear |
| 2 | `wow` | Wow | 0 | 1 | 0.3 | - | linear |
| 3 | `flutter` | Flutter | 0 | 1 | 0.25 | - | linear |
| 4 | `drive` | Drive | 0 | 1 | 0.35 | - | linear |
| 5 | `tone_hz` | Tone | 800 | 12000 | 3800 | Hz | log |
| 6 | `low_cut_hz` | Low cut | 20 | 800 | 110 | Hz | log |
| 7 | `spread` | Spread | 0 | 1 | 0.3 | - | linear |
| 8 | `mix` | Mix | 0 | 100 | 30 | % | linear |

## Use it in JUCE

CMake ([quick start](/docs/juce/index.md)):

```cmake
juce_add_module(path/to/sournd_engine)
target_include_directories(MyPlugin PRIVATE path/to/include)
target_link_libraries(MyPlugin PRIVATE sournd_engine path/to/libsournd_cabi.a)
```

C++:

```cpp
#include <sournd_engine/sournd_engine.h>

sournd::SourndEngine engine { "org.sournd.delay.driftel" };
juce::AudioProcessorValueTreeState parameters { *this, nullptr, "Parameters",
    sournd::SourndEngineParameters::createLayout (engine) };
sournd::SourndEngineParameters bridge { engine, parameters };

// prepareToPlay
engine.prepare ({ sampleRate, (juce::uint32) maximumBlock, 2 });
bridge.prepare (sampleRate);
setLatencySamples ((int) engine.latency());

// processBlock
bridge.apply ((uint32_t) buffer.getNumSamples());
juce::dsp::AudioBlock<float> block { buffer };
engine.process (juce::dsp::ProcessContextReplacing<float> { block });

// get/setStateInformation: hold getCallbackLock() around saveState / loadState,
// so state work never overlaps processBlock (full example: /docs/juce/)
```

Plain C:

```c
sournd_engine *e = NULL;
if (sournd_engine_create("org.sournd.delay.driftel", &e) == SOURND_OK) {
    sournd_engine_prepare(e, 48000.0, 512);
    sournd_engine_set_param(e, 0, 340); /* Time */
    sournd_engine_process(e, in, out, 2, frames);
    sournd_engine_destroy(e);
}
```

## How it is made

Original sOURnd design: modulated fractional delay (sinusoidal wow with band-limited random drift, sinusoidal flutter with jitter), soft tanh saturation on record, two-pole low-pass tone and one-pole low cut on each repeat inside the feedback loop.

## Ask your AI

Paste this into your coding assistant:

```text
Add the sournd engine org.sournd.delay.driftel to my JUCE plugin. Follow https://sournd.com/docs/juce/index.md
and the engine reference at https://sournd.com/engines/driftel/index.md. Expose every parameter through APVTS.
```