My friend went to put in aftermarket 6" speakers in his car. But when he going to wire them up, he didn’t know which way the positive and negative wires would go. The + and - were labeled on the speaker, but the wires were not. He just blinded “guessed” which way to hook them up, but does it matter which way they go?
These run right off the headunit, not an amplifier.
IIRC, if you reverse the speakers, you reverse the polarity, and the speaker fires out of phase. I could be wrong, though.
It’s fine as long as they’re both the same way, presuming there is some distinguishing marks on the wires. Otherwise, they are out of phase with each other, and we can have another long discussion on whether it really makes any difference (see the archives).
Wire colors vary considerably, but typically you find one color for right and another color for left, then the returns will be the same colors with a white stripe (in other words the solid is + and the striped is - ).
If one of the wires is the same color going to both speakers, that is the negative (-).
You can also check them with a multimeter. If one of the wires is grounded (to the frame of the car) then it is the negative.
Positive and negative can be hooked up backwards as long as you are consistant for both speakers (your ears can’t hear absolulte phase but they can hear phase differences due to interference patterns). However, if there is a crossover network in your speakers and it uses electrolytic capacitors, then with certain types of amplifiers it won’t work right unless you get the negative terminal in the right place.
You need to hook the wires up right. Find a test disc that will test for speaker phase, with the instructions in audible voice right on it. Sorry, you can’t have mine. Yes, it makes a big difference.
I don’t think you can actually damage anything regardless of how the wires are hooked up. You can have one speaker in phase and one speaker out of phase with no problems.
If you mix up in and out of phase speakers, the sound quality will suffer. The sound waves from each speaker will cancel each other out. This is why you must be consistent with the way you hook up.
Audiophiles claim that absolute phase is important, that it sounds “different” to have the phase reversed. (maybe it’s a crossover thing) If you have the time, use engineer_comp_geek’s rules to try and get the phase positive.
Turn everything off and disconnect both speakers at the amp. Connect a 1.5 V AA battery across the wires going to the left speaker, and have someone else note which direction the woofer cone moves. (Pulse it on & off so the other person can see it moving.) If the cone moves out, label the wire going to the positive battery terminal “positive” and the wire going to the negative terminal “negative.” If the cone moves in, label the wire going to the positive battery terminal “negative” and the wire going to the negative terminal “positive.” Repeat this procedure for the right speaker.
Aren’t speakers fed AC current?
Speakers are basically fed AC, usually in the range of 20 to 20,000 Hz. There are lots of different types of amplifiers, but basically they either put out plain old ordinary AC, or they put out a biased AC with a DC component that is constantly there. In other words, your car battery runs of of 12 volts. The radio may constantly have 6 volts on the output, then vary the AC portion so that it goes above and below 6 volts. This makes for a very cheap but very inefficient amplifier. You don’t see this sort of thing very much these days because of improvements in technology and the availabilty of amplifiers on a single chip and small, cheap, and powerful DC to DC converters.
Crossover networks with electrolytic capacitors require the polarity of the capitors to be the same as the polarity of a constant DC offset. Since most radios don’t have a constant DC offset and most speakers don’t have electrolytic capacitor crossover networks it really doesn’t matter.
Also, if the metal frame of the speaker is connected to the negative terminal and the radio grounds the negative terminal as well. Then if you connect them backwards you’ll effectively make a short circuit.
People who talk about absolute phase in audio signals make me giggle. But that’s probably a topic for great debates or the pit.