songmatch 0.1.0

Automated EQ matching between user audio and reference tracks

SongMatch

Automated EQ matching between your audio and a reference track.

SongMatch analyzes a reference track to find its loudest segment, splits both tracks into stems (vocals, drums, bass, other), applies per-stem spectral EQ matching, and recombines. It can also perform whole-mix mastering via matchering.

Features

• Per-stem EQ matching (--stems-match): Separates both tracks into 4 stems, matches the spectral profile of each stem independently, then recombines
• Whole-mix matching (--mix-match): Full-mix frequency response, RMS, stereo width, and peak amplitude matching via matchering
• Combined mode: Run both — stems-match first for tonal correction, then mix-match for overall polish
• Automatic loudest segment detection: Finds the chorus/loudest section of the reference using LUFS analysis with beat-aligned cropping
• GPU acceleration: Uses CUDA/MPS when available for faster stem separation

Installation

Requires Python 3.10+ and ffmpeg.

pip install songmatch

Or with uv:

uv pip install songmatch

Note: SongMatch pulls in large dependencies including PyTorch (~75MB) and audio-separator. First run will also download the stem separation model (~340MB).

Usage

# Per-stem EQ match
songmatch my_song.wav reference.wav --stems-match

# Whole-mix match
songmatch my_song.wav reference.wav --mix-match

# Both: per-stem EQ first, then whole-mix polish
songmatch my_song.wav reference.wav --stems-match --mix-match

At least one of --stems-match or --mix-match must be specified.

Options

Option	Default	Description
--eq-smoothing	0.33	EQ smoothing in octave fractions (0 = none)
--eq-max-gain	12.0	Max EQ boost/cut in dB
--loudness-threshold	2.0	dB below peak LUFS for segment detection
--min-segment	5.0	Minimum reference crop duration (seconds)
--max-segment	30.0	Maximum reference crop duration (seconds)
--dynamic-range-floor	4.0	Below this LRA in dB, skip cropping
--model	htdemucs_ft.yaml	Stem separation model
--output-sr	44100	Output sample rate (Hz)
--output-bits	16	Output bit depth (16 or 24)
--keep-ref-stems	false	Keep reference stem temp files
-v / --verbose	false	Debug logging

Output files

For input my_song.wav:

my_song_stemsmatched.wav          # --stems-match result
my_song_mixmatched.wav            # --mix-match result
my_song_stems/                    # EQ-matched stems (from --stems-match)
  vocals.wav
  drums.wav
  bass.wav
  other.wav

How it works

--stems-match pipeline

1. Analyze reference loudness (LUFS envelope) and find the loudest segment
2. Snap crop boundaries to nearest beats
3. Separate both reference segment and user audio into 4 stems (vocals, drums, bass, other)
4. For each stem pair: compute PSDs via Welch's method, derive a smoothed transfer function, design a FIR filter, and convolve
5. Recombine EQ-matched stems with peak normalization

--mix-match pipeline

1. Pass user audio (or stems-match output) and full reference to matchering
2. Matchering handles frequency response, RMS, stereo width, peak amplitude, and limiting

Combined mode

Stems-match runs first, then mix-match uses its output as input. Both output files are kept.

License

MIT