Wire - Speaker Polarity Test

A Python tool that tests if your left and right speakers have correct polarity (phase alignment) using your computer's microphone — similar to the auto-calibration feature found in AV receivers.

What It Does

Plays test tones through each speaker individually, records them via microphone, and analyzes the phase relationship. If one speaker has reversed polarity (swapped +/- wires), the tool will detect it.

• Tests multiple frequencies (80, 120, 160, 200, 250 Hz) for reliability
• Generates waveform visualizations showing phase alignment
• Works with any stereo speaker setup (bookshelf speakers, studio monitors, AV systems)

Installation

# Clone the repo
git clone https://github.com/jvandenbos/wire.git
cd wire

# Install dependencies
pip install numpy scipy sounddevice matplotlib

macOS Note

You may need to grant Terminal/your IDE microphone access in System Preferences → Privacy & Security → Microphone.

Usage

python speaker_polarity_test.py

Position yourself (and your Mac's microphone) roughly equidistant from both speakers, then follow the prompts.

Interpreting Results

Correlation	Meaning
+0.7 to +1.0	IN PHASE — correct polarity
-0.7 to -1.0	OUT OF PHASE — one speaker has reversed polarity
-0.3 to +0.3	INCONCLUSIVE — try reducing noise or repositioning

If you get consistent negative correlation across frequencies, check your speaker wire connections — one speaker likely has the +/- terminals swapped.

Example Output

Freq (Hz)    L Level    R Level    Correlation    Status
------------------------------------------------------------
80           0.1394     0.0814     +0.988        IN PHASE ✓
120          0.3052     0.1664     +0.996        IN PHASE ✓
160          0.3715     0.2093     +0.995        IN PHASE ✓
200          0.2418     0.1227     +0.994        IN PHASE ✓
250          0.2395     0.1155     +0.991        IN PHASE ✓

AVERAGE CORRELATION: +0.993
OVERALL: PASS - Speakers are IN PHASE (correct polarity)

The tool also generates a polarity_test_waveforms.png visualization showing the recorded waveforms and sum/difference analysis.

Keywords

speaker polarity test, phase test, speaker phase checker, audio polarity, speaker wiring test, left right speaker test, speaker diagnostic, home theater calibration, stereo phase alignment