Phase Correlation & Mono Compatibility Checker
Phase Correlation & Mono Compatibility Checker
Drop a stereo mix or stem. Get the overall phase correlation, how many dB you lose when summed to mono, how correlated the low end is, and a timeline showing where the stereo image gets risky.
+1 means left and right are identical (mono). 0 is fully decorrelated wide stereo. Negative values mean the channels cancel when summed: expect a thin, hollow mono mix. Keep the low end above +0.7.
Why mono compatibility still matters
Phones, Bluetooth speakers, club systems and many venues play mono. If parts of your stereo mix cancel when the channels are summed, the listener on those systems hears a thinner, quieter version with the vocal or the bass pushed back. The phase correlation meter measures how similar the left and right channels are: +1 is identical, 0 is fully independent, and negative numbers mean the channels fight each other. This checker gives you the overall figure, the actual level change in mono, and a timeline so you can find the risky sections.
What to fix
Low-end correlation is the one to watch. Bass and kick should read above +0.7, or the sub disappears on a mono system. Common culprits are stereo wideners on the bass, Haas delays on doubles, and wide chorus or unison synth patches. Mono the low end below 120 Hz, and check doubles with the Vocal Doubler Calculator.
Reading the timeline
Short dips during wide effects are fine; a correlation that sits near zero through the chorus means the width is built on cancellation rather than real stereo information.
FAQ
What is a good phase correlation value?
Above +0.5 for a full mix and above +0.7 for the low end. Momentary dips are normal; a constant reading near zero or below means the mix will suffer in mono.
Why does my mix get quieter in mono?
Out-of-phase content cancels when left and right are summed. The mono level change value shows exactly how much you lose; more than 2 dB is worth fixing.
How do I fix negative correlation?
Find the source: wideners, Haas delays, stereo chorus on bass, or a flipped polarity on one mic. Remove or narrow it, and keep everything below about 120 Hz in mono.
Is the file uploaded anywhere?
No. Decoding and analysis run in your browser with the Web Audio API; the audio never leaves your device.
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