Speaker Signal

[Ol_Mate]

g'day all,

I'm installing some Focal K2p's in the car and i'm running them off a rockford P4004 amp. I have an alpine 9851 head unit. Any way, I'm not too familiar with the ins and outs of sound systems when it comes to signals etc.

my intuition tells me that the signal the speakers reproduce sound from is frequency based, not voltage based. is this right?

if so, i'm wondering why on the passengers side of the car the + shows a change in freq on my meter and the - shows no signal but on the drivers side its the - that shows the signal and the + shows none.

is it something to do with the principles of stereo signals?

i'm just after an answer before i go hooking up the speakers.

[danielson]

speakers operate on ac voltage, and if your meter is set to dc, it wont read properly... the way they work is the amp knows what resistance the speakers are, eg 4ohms, and it applys a current to them. the way you work out the wattage is voltage x current = watts... its really hard to explain... go to tafe and get ur electronics trades cert..... its worth it

[Ol_Mate]

funny you should say that. I'm actually an industrial electrician.

but i mainly work with VSD/VFD's, plant control systems and PLC's etc. so i don't get to play with this stereo stuff too much.

I understand that the speakers work off AC voltage. but is it a variation in the AC voltage that tells the speaker to pump out either a bass note or a treble note. or is it a variation in the frequency of the AC voltage that tells it which note to play.

i'm more worried about possibly wiring the speakers out of phase and reducing the sound quality. I'm a bit confused as to why there is a freq/voltage change on the + on the pass. side and a freq/voltage change on the - on the drivers side.

the - on the pass. side seems to be a ground and the + on the drivers side also seems to be a ground.

hope this is clear enough. any help would be much appreciated.

[RANDY]

It can happen. I read something online that explained that one speaker could be in the opposite "phase" from the other. If you switch + and - on one speaker, both can produce more bass. (or rather, the right bass).

Apparently you can hold a AA battery (for one second) to the wires, + to + and - to -, and if the speaker pops out, it is correct. If one speaker pops INWARDS, you just run the speaker wire in the opposite hookup.

Interesting stuff, and I had to do it with my JBL 3-ways in the rear for them to sound any good. Turns out that they were out of phase with each other, and the push of one and the pull of the other on a bass note cancells each other out. Weird, and I dunno if this is a done thing, but the article was pretty in-depth.