Motorola Speaker Polarity

chezelle · Post by **chezelle** » Sat Jul 15, 2006 8:28 am

Hello,

What is the correct polarity for Motorola speaker wire?

I just bought some new Motorola 2 wire Speakers (HSN4031A). I need to put 1/8 audio plugs on them to use with scanners etc. Both wires are black but one has a raised black polarity line and the other has the white lettering on it. Which is + and - ? I just wanted to make sure I got them right.

Thanks,
Brian

kcbooboo · Post by **kcbooboo** » Sat Jul 15, 2006 8:51 am

It doesn't matter unless you're running some kind of stereophonic sound system. But if it makes you feel better, put the wire with the marking or ridge on the + or tip of the 1/8 inch connector.

Bob M.

chezelle · Post by **chezelle** » Sat Jul 15, 2006 9:12 am

Thanks for the quick response but I have already taken one of them apart and they were actually marked with the speaker wire with the raised line to the negative and the plain wire with writing the positive but sounds like it didn't matter anyway. They were rated by Motorola as 7.5 watts but after opening them up the speaker inside says FST 5084561B01 20W. I hope they are genuine Motorola.

Thanks,
Chezelle

kcbooboo · Post by **kcbooboo** » Sat Jul 15, 2006 9:20 am

That 5084561B01 is definitely a Motorola part number.

Again, it really doesn't matter as long as you're consistent with your own connections. The speaker polarity would only be important if you were running two from the same source, or in stereophonic installations.

Bob M.

wa2zdy · Post by **wa2zdy** » Sun Jul 16, 2006 5:46 am

Speakers themselves have no true "polarity." And in the case of Motorola speakers, the case is of course plastic and even with the old metal speaker cases, the voice coil is not connected to the case.

As Bob says above, in a stereo installation you want the speakers wired the same way to keep the phase relationship correct. The voice coil is exactly that - a coil - and you want both windings going in the same direction, so to speak. If you have them connected opposite, the cone of one speaker will be moving toward you while the other moves away - taking something away from the sound.

The only thing to remember about connecting speakers to Motorola equipment has naught to do with the speaker itself. It's that nearly all "modern" Motorola radios use floating audio outputs. That means neither side of the output is at ground, so you cannot ground either side of the output. To do so will almost assuredly nuke the audio output and gain you practice with the soldering iron.

jackhackett · Post by **jackhackett** » Sun Jul 16, 2006 6:41 am

wa2zdy wrote:Speakers themselves have no true "polarity." And in the case of Motorola speakers, the case is of course plastic and even with the old metal speaker cases, the voice coil is not connected to the case.

Sorry to nitpick, but dynamic speakers absolutely have a polarity, and polarity has nothing to do with anything being connected to the case. As you and others have noted, the way they are connected matters to the direction of movement of the cone and phase of the output, therefore they have a polarity.

Bruce1807 · Post by **Bruce1807** » Sun Jul 16, 2006 7:30 am

When was the last time Mot releases a radio with a Dynamic Speaker
I mean I'm sure my old 51X11 has dynamic but where I live no more AM so it sits on the mantle piece.

jim · Post by **jim** » Sun Jul 16, 2006 2:18 pm

What exactly do you think a dynamic speaker is? All Motorola radios have them.

As for polarity.....it has to be correct on multiple speaker systems regardless of stereo.

If one is on an outward cycle and the other is going inward, you will get cancellation and have less volume.

Don't believe it? Find a vehicle with dual siren speakers and reverse one of the speaker leads and listen to the total lack of volume.

Will · Post by **Will** » Sun Jul 16, 2006 2:43 pm

You guys are showing your age!
Dynamic speaker , yes, but Jack must have ment to say with perment magnet. Not the older Electro dynamic speaker that gets it's magnetisum from a DC field coil that is usally the filter choke in the radio's power supply.

Bruce1807 · Post by **Bruce1807** » Sun Jul 16, 2006 3:14 pm

Actually not showing my age I just collect some old Mot stuff.
Dynamic speaker would be interperated as Electro Dynamic by the old timers.That is how I interpereted it and with them polarity matters.

Jim you said it perfectly 2 speakers you will notice an effect. That is one speaker out of phase with the other and cancellations occur
It makes no difference which way you wire a single speaker as long as there are no ground issues.
The original poster is talking about an external radio speaker, not a dual speaker siren, not a home or car stereo but a single speaker.
It makes absolutely no difference which way it wired on volume, quality , frequency response, distortion, anything at all. How can a single speaker be out of phase. Out of phase with what?
Yes they do have polarity if you stick a meter on ohms connected one way will push the cone out, the other will pull the cone in but again unless one side uses a ground return it means nothing if only one speaker is used.
You can also reverse both siren speakers and no change will occur as they are still in phase.

Will · Post by **Will** » Sun Jul 16, 2006 10:31 pm

I have had to change factory wired speakers' polarity on a few mobile radios to cut down on feedback from officers handheld, and other radios.

I usally does not matter, as has been pointed out.

Motorola Speaker Polarity

Motorola Speaker Polarity

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