Phase Alignment Checker

Upload any stereo audio file and instantly check stereo correlation, mono compatibility, and get warnings about phase cancellation. Free, no signup.

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What is a phase alignment checker?

A phase alignment checker measures the stereo correlation between the left and right channels of your audio. Correlation ranges from −1 (perfectly out of phase — left and right are inverted) to +1 (perfectly in phase — mono playback is identical to stereo). Values near 0 mean the channels share little in common, often due to stereo widening effects, Haas delays, or polarity-inverted mics. Our free phase alignment checker reads your file, computes the average correlation, and warns you about phase cancellation that will hurt your mix on mono playback systems.

Why phase issues matter in mixing

Phase issues mixing problems are one of the most common silent killers of a good track. When your left and right channels are partially out of phase, the signal cancels itself out when summed to mono — bass disappears, vocals thin out, and the whole mix loses weight. Many listeners hear your music in mono: phone speakers, smart speakers, Bluetooth in mono mode, and car systems that sum channels. A phase alignment checker catches these problems before release so you can fix polarity, reduce stereo widening, or adjust mic placement.

How to read stereo correlation

A healthy mix reads between +0.5 and +1.0 on the correlation meter. Below +0.5 indicates widening that may compromise mono; below 0.2 is a red flag; a negative value means your channels are inverted and will cancel badly in mono. Use this phase alignment checker alongside your DAW's correlation meter — if you see low readings, solo individual elements to find the offender (typically a stereo widener, doubler, or a multi-mic'd source like drums).

Typical correlation values

CorrelationStatusWhat it means
+0.8 to +1.0ExcellentTight, mono-safe stereo
+0.5 to +0.8GoodHealthy width, safe in mono
+0.2 to +0.5CautionWide — some elements may thin in mono
0.0 to +0.2RiskSignificant cancellation in mono
NegativeInvertedChannels out of phase — fix polarity

How to fix phase cancellation

If your correlation is low or negative, identify the offending element by soloing tracks while watching a correlation meter. Common fixes: flip polarity on one channel of a stereo mic pair, reduce the depth on a stereo widener or Haas delays, replace phase-shift widenens with short delays (5–15 ms), and always check your drum overheads and room mics for phase alignment before mixing.