Phase Coherence Checker

Analyzes the phase relationship between left and right channels across frequency bands. Detects polarity issues, inter-channel delay, and frequency-specific phase cancellation.

Parameters

Parameter Type Default Description
file_path string required Path to stereo audio file
bands number 6 Number of frequency bands to analyze

Example Output

$ analyze_phase stereo-bus.wav

Phase Analysis Overall coherence: 0.84 Polarity: OK (positive correlation) Inter-channel delay: 0.0 ms

Per-band Coherence: Sub (20-60 Hz): 0.98 Low (60-250 Hz): 0.92 Low-mid (250-2k Hz): 0.87 High-mid (2k-6k Hz): 0.71 High (6k-12k Hz): 0.62 Air (12k-20k Hz): 0.55

What the Numbers Mean

  • Overall Coherence — Correlation between L and R channels averaged across all bands. 1.0 = perfectly mono-compatible. 0.0 = completely uncorrelated (widest stereo). Below 0.5 = likely phase issues. Negative = polarity inverted.

  • Polarity — Whether the channels are in-phase (positive) or out-of-phase (negative). Out-of-phase audio cancels when summed to mono. This catches reversed polarity from mic placement or routing errors.

  • Inter-channel Delay — Time offset between L and R in milliseconds. Non-zero values indicate a timing misalignment that can cause frequency-dependent cancellation (comb filtering). Common in multi-mic setups.

  • Per-band Coherence — Phase coherence broken down by frequency range. Low frequencies should be highly coherent (0.9+) for solid bass in mono. Higher frequencies can be lower (0.5-0.8) — that’s normal stereo width from reverb, panning, and stereo effects.

Example Prompts

Mono compatibility

Check if my mix is mono-compatible — analyze the phase of mix-stereo.wav

Phase issues

Are there phase cancellation problems in my drum overheads?

Bass check

Is the low end in phase? I want it to translate to mono club systems

  • analyze_stereo — Width and balance measurement (complementary to phase analysis)
  • compare_phase — Compare phase between two different sources
  • detect_problems — Flags phase issues as part of problem detection

Pro tip

If per-band coherence drops below 0.5 in the sub/low range, your bass will disappear on mono systems (club PAs, phone speakers, Bluetooth speakers). Use a mono-maker or stereo narrowing plugin below 150 Hz.