Crossovers?

Im updating the rear speakers in my car, in the space there is brackets for 2 5.25 speakers, so total of 4 speakers in the back. There are wires already connected to 1 speaker to have an additional speaker there will I need to use a crossover! Just that most of the crossovers I can see on trademe only have an input for 1 speaker, 1 sub woofer, and 1 tweeter. Any help would be great. Thanks!

It's wrong to crossover. If you're born a man or woman, you should just accept it and stay that way.

Tony is absolutely correct! And he/she is speaking from personal experience too.

Crossovers are not for adding additional speakers.They are specifically made to route different frequency bands to different speakers.They take the high end frequencies and route it to the tweeter and low freqs are routed to the woofer.Adding a crossover with the intent of simply adding more speakers will achieve nothing.You need to look at the power output rating of the head unit and see if it will cope with additional speakers.

Yep. I told you that you should have just left yourself the way you were.

If you already have 2 speakers there, take a note of the impedance - it's probably 3~4 ohms. If you are wanting to replace each of these with a pair, then you should remove the originals and replace them with 2 x 8 ohm speakers wired in parallel OR 2 x 2 ohm speakers wired in series - (8 ohm speakers are probably more readily available). A crossover is not required.
If, however, you are wanting to replace the present speakers with a woofer/tweeter pair on each side, then you will need a crossover network.
The speakers and crossover will all need to be the same impedance as the original speakers. Each crossover will have 1 input from the amplifier and will have 2 outputs - 1 for the woofer and 1 for the tweeter.

What the others are talking about is in a different part of the car - the trannys-mission.

LOL, "lets do the timewarp."