Whit two active speakers ?

Question

do i still need an external amplifier and a separate subwoofer ?

thank you. !

Answer 1

That depends upon the power of your head unit and the capacity of your speakers.  If you have a sparate sub, use an external amp.  Only if you're head unit is powerful enough can you split the signal and use an L-pad with a choke to power the sub.

Answer 2

You do NOT need an amp with active speakers.

Whether you need a separate sub is up to you.