I DIY my CAr ICE I have A pair 6x9 5way speaker ,a 4 channel amplifier and 12'' subwoofer.

Diagram inside my Car.

CD player > AMplifier > 3 channel a pair of 6x9 speaker and subwoofer too.

what use for crossover ?
Which place should i put cross over after amplifier?

Me noob

i DIy all my self

OK, I'm not an expert in ICE but I have some experience in P.A systems and I believe they work the same way too.

A crossover is also known as a frequency divider.
Normally it is installed like this in a P.A. system :

Mixer output --> EQ --> Compressor --> Crossover --> Amplifire --> Speakers.

A crossover/frequency divider separates the low, mid, and high frequency before it goes into the low (bass) amp, mid amp, and high (treble) amp.

Then only the low amp would be connected to the woofer, while the mid/high amp connected to the tweeters.

wat crossover is it?
active or passive?
active crossover is pre amp
passive crossover is post amp

passive crossover

the connection is like this

HU->AMP->PASSIVE->SPEAKER

There's some diagram you can refer.

http://forum.lowyat.net/index.php?showtopic=342987

thank you guys