Wiring up car subwoofer box

[Mark.p]

hi guys I have a sub box with 4 terminals. How do I wire up my mono block amp to these 4 terminals.

[GTSBoy]

That will depend on why it has 4 terminals. Is it a single driver with twin voice coils? Is it an isobaric box with two drivers? (Actually, if the answer to either of those questions is yes then there's probably little difference in how you wire it up).

Twin coil drivers will either have 2x 8 ohm voice coils or, more likely, 2x 4 ohm voice coils. Wire them up in series and you get double the resistance and half the power. (ie, 8 ohm coils in series gives 16 ohms, 4 ohm coils in series gives 8 ohms). Wire them up in parallel and you get half the resistance and double the power (8s give 4, 4s give 2). And note also that when I say "half" and "double", I mean half and double of what the single coils give you. The two results will be a factor of 4 different from each other. ie, for the 4 ohm coils case, you get 8 ohms or 2 ohms for the two options.

Whether you can drive a 2 ohm load will depend on your amplifier. It is possible, but not be taken for granted.

If the box is an isobaric, you must drive both drivers. If the box is a single driver with dual coils, you do have the option of driving only one coil - so in the 4 ohm case you actually do have the choice of a 2 ohm, 4 ohm and an 8 ohm load for the amp. There are many factors around pluses and minuses in these options that you should research.

But the main factor here is you need to know what you have, because all of what I said above can't help you if you don't know what you have and what your amp can drive.