Rear speaker wiring and ohms?

[ktthecarguy]

Hi there,
I want to put new speakers in the rear pillars and the doors in my '92 Safari. I heard one time that the speaker ohms should be the same front to back, so as not to overload the amp in the head unit. I have an older Sony CD head unit (sorry, don't have the model handy).

My question is, were the original speakers wired in series, the pillar to the door? That's what the wiring looks like, anyway. And is the impedence important? For example, if I put 5" speakers with 4 ohms up front, should I use 4" speakers with 2 ohms in the pillars, and 5" speakers with 2 ohms in the doors?

Does this make any sense?
Thanks,
KT

[Jasen]

Not knowing the specs of your deck I'm going to say no. As far as I know, head units are typically 4 ohms. Running 2 ohm speakers will damage the amp in the deck and I believe the speaker.
If you us external amps you need to make sure they are stable down to 2 ohms.
As far as the front speakers being wired in series, are you taking a full range and a tweeter. Typically the tweeter would be wired through a cross over between the full range speaker and tweeter, or they both run through a cross over where you have one set of wires in and two set out, one for the full range and one for the tweeter, which are set at different cross over points.

[rev_les]

I haven't checked the wiring, but 2 2 ohm speakers in series would be 4 ohms....... that being said, I don't recall seeing door speakers available in 2 ohm configuration, but I've been out of audio for a couple of years.I think mine were wired parallel with a coil on the rear door drivers to cut out high frequency.If you're just looking for a simple upgrade in sound, just ditch the rear door speakers, and run the ones in the c pillar,running a typical head unit at less than 4 ohms is gonna kill it.

[tedanderson]

They don't necessarily have to carry the same load. It's just that as long as the load isn't lower than 4 ohms, no matter how you slice it, you will be fine. One thing that you can do is install a 1/4-watt or 1/2-watt resistor inline with each 4 ohm speaker to bring it up to 8 ohms and then when you connect the rear and pillar speakers in parallel, you will still maintain that 4-ohm load.