Phasewise: Speaker Polarity

A speaker polarity tester that compares each speaker with a reference of the same kind, shows the evidence, and says "can't tell" instead of guessing.

Coming to Google PlayFinished and waiting for its Google Play listing.

Free
Works offline
No account
No subscription

App languages: English · Español · Português · Deutsch · Italiano

Also in: Español · Português (Brasil) · Deutsch · Italiano

Phasewise checks speaker wiring by comparison. It plays six test sweeps, listens through your phone's microphone, and compares each speaker with a reference of the same kind, measured the same way. Whatever the phone, the amplifier and a Bluetooth link do to the signal is the same for both, so what is left is the difference in wiring.

Every result shows its evidence: both responses on one graph, the shape match, the confidence and how many sweeps agreed. If the sweeps disagree or the room is too noisy, it says "can't tell" and why, rather than picking a side.

Screenshots

Why we built it

Results that jump between green and red. Six sweeps per test that must be found, stand out from the noise and agree with each other, or the answer is "can't tell".
A verdict from one pulse, with no way to check it. Both responses on one graph, with the shape match, the confidence and how many sweeps agreed.
Unskippable ads and permissions the job doesn't need. No ad before or during a test, and the only permission it asks for is the microphone, at your first test.
One speaker at a time, nothing to keep. Layouts for car audio, stereo, home theater and PA, saved systems, and a PDF report or CSV export.

Features

Why other polarity checkers jump between green and red

They read one pulse. But a phone, its amplifier, a Bluetooth link and a microphone can each flip the signal, and a speaker rings in ways that make a single pulse ambiguous. Phasewise doesn't guess. It compares each speaker with a reference of the same kind, measured the same way, so everything unknown cancels and only the difference in wiring is left.

A result that shows its work

Six sweeps per test: they must be found, stand out from the noise and agree with each other
See both responses on one graph: a reversed speaker visibly mirrors the reference
Shape match, confidence and how many sweeps agreed, for every speaker
"Can't tell" with the reason and what to change, never a coin toss
Check one speaker by hand with a battery, mark it, and results become Correct or Reversed instead of a comparison

Check a whole system

Layouts for car audio, stereo, home theater and PA, or your own list
Speakers grouped as woofers, midranges, tweeters, subs and full range: a tweeter is never judged against a woofer
Moves on to the next speaker for you
Saved systems, a PDF report for the customer, CSV export

Play it from anything

Through the phone by cable, USB or Bluetooth: latency doesn't matter
No easy input? Save the test track as a WAV on a USB stick and play it from the head unit
Or use a second phone as the player

A test bench in your pocket

Tone generator: sine, sweeps, pink and white noise, left, right or inverted
Stereo listening test: left, right, in-phase and out-of-phase noise, no microphone needed
Delay finder: which side reaches your seat first, in milliseconds
Time alignment calculator: distances in, delays out, for a DSP or head unit
Spectrum and relative level, for balancing speakers
Rattle sweep, bass sweep, 1 kHz tone, all exportable as WAV
Phone self-test: does this phone give steady readings?

Honest about what a phone can do

A phone can't know the absolute polarity of a speaker on its own, so Phasewise doesn't claim to. Without a hand-checked reference it says "matches" or "reversed against the reference". It compares speakers of the same kind; it can't compare a sub with a tweeter, and many crossovers invert a driver on purpose, which the Guide explains. Phone microphones aren't calibrated, so levels are relative.

No ads in your way

No ad ever plays before or during a test, and the only permission it asks for is the microphone, at your first test. Sound is analysed on the phone, never saved or sent. No account. Works offline. Backup to one file. Free with ads on the lists; one optional purchase removes them, and every feature stays free either way.

How it works

A phone, an amplifier, a Bluetooth link and a microphone can each invert the signal, so a single reading can't give absolute polarity. Phasewise compares speakers of the same kind through the same phone and output, which leaves only the wiring difference.

Check one speaker by hand with a battery and mark it, and results become Correct or Reversed instead of a comparison. That holds for that phone and that output.

The analysis has been tested on simulated speakers and rooms, including pairs of different speakers, where it gave no wrong verdict and a few "can't tell" answers. Real rooms and phones vary, which is why every result shows its evidence.

Honest limits

A phone can't know a speaker's absolute polarity on its own. Without a hand-checked reference, Phasewise only says matches or reversed against the reference.
It compares speakers of the same kind. It can't compare a tweeter with a woofer or a sub with mains, and many crossovers invert a driver on purpose, which the Guide explains.
Phone microphones aren't calibrated, so levels and the spectrum are relative. Its verdicts haven't been checked on every phone and speaker system, so treat a surprising result as a reason to look at the wiring, not as proof.

Questions

Can a phone test speaker polarity?

It can compare speakers. Testing absolute polarity from a phone alone isn't reliable, because the phone's output and microphone can each invert the signal. Phasewise compares each speaker with a reference of the same kind, so those unknowns cancel, and it can give Correct or Reversed once you have checked one speaker by hand with a battery.

Why do polarity checker apps give different answers each time?

Many read a single pulse, and a speaker rings in ways that make one pulse ambiguous. Phasewise uses six sweeps that must agree, and says "can't tell" when they don't.

Can I test a tweeter against a woofer?

No. Speakers are grouped by kind, and a tweeter is never judged against a woofer. Many crossovers invert a driver on purpose, so a difference there isn't a wiring fault.

Does it work over Bluetooth or from a head unit?

You can play the test through the phone by cable, USB or Bluetooth, because latency doesn't matter. If the system has no easy input, save the test track as a WAV on a USB stick and play it from the head unit, or use a second phone as the player.

Does it record me?

Sound is analysed on the phone and never saved or sent. The microphone is used only while a test or measurement is running.

Private and offline

Runs entirely on your phone and works offline. No account, no sign-up, and your data stays on your device. The app shows ads through Google AdMob; see the privacy policy. Privacy policy.

Free. An optional one-time purchase removes the ads; nothing is locked and there is no subscription.