I have two sony box speakers they are 4 ohms each but i wanna build a speaker box to transfer those sony speaker to the one im building .... what kind of crossover i need that could hold my 2 4ohms speakers.... do i take one of the crossover that has inside and put with both speakers or get an 8 ohms that could take both speakers 4ohm ? Idk what to do please help
Assuming that you will have a stereo amp to drive the single speaker you don't have to combine the speakers electrically. You can just mount them into a single cabinet and use the existing crossovers, wiring, and terminals. That's the simplest way to do it.
If you want to use a single channel amp you will need a crossover that can maintain an impedance that the amp can handle. A common arrangement is to use the two woofers with one tweeter like this https/www.parts-express.com/resources-building-a-crossover
or you can try this http/www.apicsllc.com/apics/Misc/filter2.html
Using two tweeters usually screws things up.