hi. i need to check the polarity of my speakers, but they are behind my front door panels and under the tray in the back window. everyone keeps sayin put a 1.5 volt battery on there and see which way the cone moves. problem is, i will be in the trunk (at the amp testing the wires) and since they speakers are covered up anyway, i wont be able to see which way they move. can this test be done with a multimeter? that would be easy. i want to aviod tearing apart my interior. thanks
Do a series of tests by switching the speaker wires at the amplifier. Using a test tone will help you hear the difference in db better than playing normal music or you could try both. Manipulate the RCA inputs (or balance and fade on the deck) so that you can test one set of speakers at a time, left compared to right, and fronts compared to rears. The output will be much louder when a set of speakers are in phase. It's easiest to tell by using bass tones, something all the speakers can play, like about 60 - 80 Hz.
Make a chart before you start with the steps of the testing procedure, and include every detail such as "switch balance to the left, fade to the rear". As you test, check off each step, and this will go a lot smoother. This method is time-consuming, but when you don't have to disassemble the car it can save a lot of time.
You can alternately use a DMM to test AC voltage output at the amp speaker terminals. The reading will be a positive number if the leads are on like polarity, or it will read a negative number if you have positive lead on a negative terminal. This is more confusing, though, because of the way bridgeable amplifiers work (see about halfway down the page HERE). It's difficult to be sure which terminal is supposed to be positive, and the meter reading might also be difficult to decipher. The listening test is the easiest to do.
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He just wants the pollarity of the wires, to find out that its simple. Take an AA battery and one wire to one side and one to the other. If you here a crackle then thats the right wiring see which one you gave to + on the battery and thats you + and same with negative. As for meters my meter has a signal out that i can vary the hz's.
Uh....you would get a crackle sound whether you have the battery on the right wires or not. If you can't see the movement of the speaker you still won't know if the polarity is right.
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Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.
I used that trick alot and it only actually made a noise when i had the right pollarity, but steve have more experience then me so i would take his word over mine on this.
godblessdremil wrote:
I used that trick alot and it only actually made a noise when i had the right pollarity, but steve have more experience then me so i would take his word over mine on this.
A speaker will make a noise no matter the polarity of the battery.
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