i have an FC, and an 8inch ported base tube in the back... i was wondering, what is the best positioning for it?
right now, i have the port facing the rear of the car as it seemed to sound the best after trying different positions...

also, would it be good if i put fibreglass or insulator inside the tube? i heard somewhere that this could be good...

 

I don't know about putting stuff inside the tube...I suppose you could try it and see.

As for placement, the tubes are supposed to point into the corner. I have mine going sideways across the back, pointing into the corner there. Your way should be just as good (maybe better, who knows?).

jds

 

The fiberglass "insulation" effectively slows down the speed of sound inside the tube, effectively making it behave like a larger enclosure. The physics of the acoustics are a bit more complicated than that, but that's it in a nutshell.

Depending of the speakers/porting, it may do nothing at all, or at kill your resonance & volume... ymmv.