Picture this: your Digitakt is on Input A pumping beats, a turntable on Input B spinning vinyl, and a mic on Input C catching vocals — all three flowing into a single multichannel output, each landing on its own stereo track. Need to blend the Digitakt and turntable together into one track for a live mashup? Dial the gain and it's done. Want to isolate the mic on its own output for separate processing? One click. A 3D spectrogram waterfall lights up every frequency in real time so you can see exactly what's happening across the full spectrum.
LF Music Mapper connects up to 3 input devices to a multichannel output with per-channel mixing, gain control, and live visualization. Whether you're routing hardware into a multichannel interface for a live set, layering a drum machine with a synth and a sampler, or just need a clean way to get three sources onto four stereo tracks — this is the tool.
Built by @LofiFren
- Up to 3 simultaneous input devices - connect a Digitakt, turntable, synth, or any audio interface and mix them together
- Flexible channel mapping - route any input channel to any output track with per-channel gain, blend up to 3 sources per channel
- 4 stereo output tracks - supports multichannel output devices (up to 8 channels)
- 3D spectrogram waterfall - real-time perspective-projected visualization with frequency, time, and amplitude; rich color mapping from deep blue (silence) through cyan, green, yellow, orange, red to white (loudest)
- Level meters - 8-channel VU meters with peak hold and clip detection
- 32-bit float / 48kHz+ - professional audio quality with selectable sample rate (44.1kHz, 48kHz, 96kHz)
- Callback-based audio engine - low-latency output driven by the hardware audio clock with ring buffer synchronization between input and output devices
- Soft limiter -
tanhsoft clipping prevents digital distortion on hot signals - Quick presets - one-click stereo, mono, and multi-device routing setups per input device
- Auto-apply mapping - routing changes take effect immediately, no apply button needed
- USB hot-plug support - refresh device list to detect newly connected USB audio interfaces
- Python 3.11+
- macOS, Windows, or Linux
- An audio interface with multiple outputs for full multichannel routing (stereo output works too)
git clone https://github.com/LofiFren/LF_MusicMapper.git
cd LF_MusicMapper
pip install -r requirements.txt| Package | Purpose |
|---|---|
| PyAudio | Audio stream I/O via PortAudio |
| NumPy | Audio buffer processing and visualization rendering |
| SciPy | FFT for spectrum analysis |
| PyQt5 or PySide2 | GUI framework |
python3.11 mapper.py- Input A selects your primary input device automatically
- Input B / C - pick a second or third input device (select "-- Off --" to disable)
- Output Device - choose your multichannel output (e.g. Roland S-4, Torso S-4)
- Output Channels - select how many channels/tracks to use
- Sample Rate - choose 44100, 48000, or 96000 Hz
- Track Routing - configure which inputs feed each output track, or use the quick-set buttons
- Click Start Routing to begin
Each output track has Left and Right channels. For each channel you can:
- Click Mix to open a dialog where you blend up to 3 input sources with individual gain sliders
- Use per-device Stereo / Mono quick buttons (e.g. "A Stereo", "B1", "B2")
- Use the Presets row for common routing patterns
Input channels are labeled by device: A1, A2 (Input A), B1, B2 (Input B), etc.
Set DEBUG = True at the top of mapper.py to enable:
- Console debug logging for device detection, mapping, and stream events
audio_diag.logfile with per-second metrics: callback rate, underruns, peak levels, stale reads, and callback timing
- Callback-based I/O - input and output streams use PortAudio callbacks (not blocking reads/writes) for minimal latency
- Ring buffer sync - each input device pushes audio into a
deque(maxlen=4)ring buffer; the output callback pops fresh frames, absorbing clock drift between separate hardware devices - Soft clipping -
np.tanh()applied to output prevents digital clipping artifacts - GIL-friendly visualization - spectrogram colors computed in numpy (releases GIL), then rendered as image strips with lightweight QPainter calls to avoid starving the audio thread
MIT