Is inverting polarity the same as shifting phase?

No, and the distinction matters. A phase shift delays the waveform, usually by an amount that varies with frequency, while inverting polarity simply mirrors it about the horizontal axis by multiplying every sample by minus one. That is why an inversion can cancel a duplicate exactly but cannot align a source that is arriving late.

How do I tell whether my channels are out of polarity?

Fold the file to mono and compare the level with the stereo version. If the mono sum is noticeably quieter, the two channels are cancelling, which is the signature of opposite polarity. The tool has no meter of its own, so that test is described in its guidance rather than measured for you.

Why are both checkboxes ticked by default?

Because inverting everything is the common case when the file needs to be compared with a reference or fed into a null test. The moment you want to fix a pair that is cancelling each other, untick one side so only one channel flips, which is the operation that restores the reinforcement.

Can inverting a channel damage my mix?

It can cancel content if you invert the wrong thing. Where a mix has a strong centred component, flipping one channel of the pair removes that centre outright. Nothing is destroyed on disk, so the safe approach is to keep the original and audition the inverted version before using it anywhere.

Does it work on mono files?

It will invert a mono file if you ask, since only one channel is present to negate. The interesting behaviour needs two channels, though, and for a mono file the operation is equivalent to flipping the whole signal, which is what the phase inverter is named for.

Channel Inverter

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Phase Inverter

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Mid/Side Processor

Process mid and side separately

Channel Inverter flips the polarity of the left channel, the right channel or both, by multiplying the selected side by minus one. It is the polarity half of stereo repair, kept separate from anything that moves or mixes channels.

What is Channel Inverter?

Load a file, tick the channels you want flipped and the result is written out. The footer explains the test that matters: if a summed mono version of the file gets quieter than the original, the two channels are out of polarity with each other, and inverting one of them restores the level.

What the panel offers:

A checkbox for the left channel and a checkbox for the right, both ticked by default so the file inverts as it loads.
Exact negation, which multiplies every selected sample by minus one with no scaling and no smoothing.
A written mono sum test rather than a measurement, because the tool has no metering of its own.
An output WAV named after the source with an inverted suffix.

Polarity inversion is not time alignment, and it is not a phase shift in the delay sense. Multiplying a waveform by minus one mirrors it about the horizontal axis, so where two copies of the same signal meet with opposite polarity they cancel and the summed result collapses towards silence. That is why the practical use is a pair of sources that ought to reinforce each other but do not: a two microphone capture with one cable wired backwards, a split feed through a wrongly pinned adapter, or a doubling track that has passed through a polarity flipping stage. The operation is verified as exact negation, so nothing is added, removed or resampled along the way, and inverting the same channel twice returns the original samples. The most common real case is a two microphone pair on one source, where one microphone ended up inverted relative to the other and the combined result sounds thin and hollow; flipping the offending channel restores the reinforcement, and the low end comes back long before any measurement is made. The second use is deliberate, because inverting a copy and summing it with the original at matched level leaves whatever the two versions do not share.

What it will not do:

It flips polarity only; a timing offset needs a delay rather than an inversion.
Cancellation is not repair, so a genuinely damaged channel stays damaged.
Choosing the wrong channels can deliberately cancel content, which is useful for a null test and destructive when you wanted the file intact.
Nothing here measures or reports cancellation, so the mono sum test has to be run in another tool.
It is not a phase rotation, so it cannot shift frequency relationships the way an all pass filter can.
An incomplete cancellation usually means timing, level or filtering is involved as well, not polarity alone.

Use it when a mono fold down loses level and you have traced the cause to polarity, and use it in reverse when a null test should reveal what two takes do not share. If the channels sit in the wrong places rather than the wrong polarity, the swapper is the tool you want, and if the whole file needs flipping at once rather than a chosen side, the phase inverter does that in one step.

How to use Channel Inverter

Load a stereo file and note which channels are currently ticked; both are selected by default.
Untick the side that should keep its polarity so that only one side of the pair is inverted.
Run the pass, which negates every sample of the selected channels exactly.
Download the inverted WAV and check the mono sum elsewhere to confirm the cancellation is gone.

When to use Channel Inverter vs related tools

Channel Inverter is the right tool when one side of a stereo pair needs flipping to restore reinforcement. Phase Inverter is the same negation applied to every channel at once, which suits a whole file that is out of polarity with a reference. When the channels are misplaced rather than mis-polarised, Left/Right Channel Swapper exchanges them, and when the relationship itself needs rebuilding, Channel Mixer reaches parts of the problem that an inversion cannot.

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