Speaker Polarity without getting to the speaker? - AVS Forum
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post #1 of 10 Old 07-02-2014, 08:17 AM - Thread Starter
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Speaker Polarity without getting to the speaker?

Ok, so I have a very odd situation... I know how to check what speaker wire goes where, check polarity, etc... I have two speakers that I cannot get too. They are about 30 in a ceiling in the middle of a room and I have no way of getting to the speaker without renting some scaffolding or something like that. Some of the other wires in the house were backwards and I really want to figure out if these two are wired correctly or backwards. Is there any way of figuring this out? Also, they have grills over the speaker, so I can't see the actual speaker at all. I just want to make sure they are hooked up right on the other end and have no way of telling.

I have seen some devices made for cars that you play music thru the speaker and a little box basically listens and tells you if it is in phase or not. Is that my best route or does anyone have any suggestions that might help me out? Any help is greatly appreciated!! I am stuck at this point.
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post #2 of 10 Old 07-02-2014, 09:07 PM
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It's going to be difficult without being able to see the speakers, but there is one thing you can try. First try using the connections as they are labeled (+/-). Try listening to music and listen for the lower tones (bass) content. Since bass is mono, if the speakers are out of phase it will sound weak because it is being cancelled (one one moving in while the other is moving out). If wired correctly, in phase, the bass will be more prominent.

If the speakers don't produce much bass, the only way I know to check the phase requires being able to see the cones. Using a AA battery touch the speaker wires to the +\- of the speakers and note if the cones move in or out. Then make both speakers move the same way using the same polarity on the battery.
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post #3 of 10 Old 07-05-2014, 02:43 PM
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The old digital video essentials disk for DVD has an audio test for phase. I'm sure there are other sources. Have someone with 2 good ears (lol) listen, they should be able to tell right away.
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post #4 of 10 Old 07-05-2014, 02:54 PM
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Quote:
Originally Posted by fred37 View Post
The old digital video essentials disk for DVD has an audio test for phase. I'm sure there are other sources. Have someone with 2 good ears (lol) listen, they should be able to tell right away.
The Digital Essentials disc I have says to listen if the sound is focused or diffuse. If in phase you have a defined center image. Out of phase is non- focused and diffuse. The trouble is the speakers are on the ceiling and may be difficult to tell. The test using bass when used for front speakers has you place the speakers face to face so the bass cancelation is easier to detect when out of phase. Just tried to adapt the same behavior for ceiling placement. Never tried it, but worth a try.
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post #5 of 10 Old 07-05-2014, 04:12 PM
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Most better AV receivers will tell you when you run their audio setup (Audissy, MCACC etc.).


I have a wire toner that produces a 400hz tone through the speakers.
http://www.amazon.com/Fluke-Networks.../dp/B000FTADX0


To young ears it is easy to hear out of phase. Just practice the following on speakers you know the polarity of.


Connect the leads from the toner to the speaker wires, one from each speaker to the red and one from each speaker to the black.
Now reverse the wires from one of the speakers.
When you think phase is the same temporarily mark the positive ends.
Now test one of the speakers with a speaker you know the polarity of.
When those are in phase you will know the polarity.


If you can't get your hands on a toner use a AA or AAA battery and touch the wires of both speakers a once to make them "click".
Again, to hear "in phase" practise on speakers you know are correct.
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post #6 of 10 Old 07-06-2014, 04:22 AM
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So can anyone explain the AA battery test for polarity a little more in depth? I would like to test the polarity on my subwoofers.

If the speaker wires are wired to the battery, how do you tell if it's in phase versus out of phase? Does it mean in phase if the driver moves in, and out of phase if the driver moves out?
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post #7 of 10 Old 07-06-2014, 04:52 AM
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Quote:
Originally Posted by Martycool007 View Post
So can anyone explain the AA battery test for polarity a little more in depth? I would like to test the polarity on my subwoofers.

If the speaker wires are wired to the battery, how do you tell if it's in phase versus out of phase? Does it mean in phase if the driver moves in, and out of phase if the driver moves out?
The standard for speaker polarity is that with a positive voltage applied to the positive speaker terminal, the cone moves out.

http://www.techguys.ca/howto/speaker.html
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post #8 of 10 Old 07-08-2014, 12:29 PM
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Exclamation

]So can anyone explain the AA battery test for polarity a little more in depth? I would like to test the polarity on my subwoofers.

If the speaker wires are wired to the battery, how do you tell if it's in phase versus out of phase? Does it mean in phase if the driver moves in, and out of phase if the driver moves out?[/QUOTE]


Don't wire the speakers to the battery, just make intermittent contact so the speakers make a scratching sound.
Phase is how the speakers move in relation to each other.
Polarity is the plus and minus on the speaker terminals.
If the polarity on all speakers is reversed the speakers will still be in phase.
Speakers should be wired with proper polarity but you probably won't be able to tell
by listening as long as they are in phase.
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post #9 of 10 Old 07-08-2014, 12:58 PM
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If the battery thing doesn't produce an answer, try sending correlated (both channels have the exact same signal) white/pink noise to the pair of speakers.

It should sound really weird (move your head around) when they are out of phase, and a lot less so when in phase.

White/pink being the hissing noise like off-channel static on a radio.

Apply the noise, listen, change the polarity on ONE speaker, listen again...

Phase will probably be important than polarity since they are so distant to the listener. Try to get the phase right.

Later you can listen normally with the rest of the system and play with the polarity (change on both speakers), to see which, if either, is better.

If it all sounds the same then it just didn't matter in your instance.

I'll be back later...



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post #10 of 10 Old 07-08-2014, 01:19 PM
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You can use a microphone hooked up to a computer soundcard and record the wave when applying the battery trick posted above. Use an audio application where you can see the recorded wave. (Or some iPhone recorder app)

You can calibrate your recorder setup using a loud speaker where you can see the woofer moving using the battery trick.


The direction of the initial pulse in the recorded wave shows the absolute polarity in comparison to the known loudspeaker you.used to calibrate.

Last edited by Frank Derks; 07-08-2014 at 01:34 PM.
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