What does inverting the subwoofer do for performance?? Is this completely cosmetic or does it do something differently than normally mounting the sub?? Also, How can you mount a sub backwards if the trim piece only fits on one way?? Is there a different trim piece needed to do this type of mounting?? Thanks everybody.

Cosmetic only, aside from the fact that you don't need to subtract the subwoofers displacement from the enclosure nothing changes. I'm not sure about what you mean with the trim ring...

Purely cosmetic.  Sometime people do it because of space constraints & if they have multiple subs it can allow them to make the enclosure a few tenths of a cubic foot smaller.

 

Not sure what you mean about trim ring.  Most subs have a gasket that functions correctly both mounted regular & inverted.  Some subs do, however, have the basket design in such a way that inverted mounting isn't easily accomplished.

Cool. That's what I thought but wasn't sure. I haven't tried to inverted my BL but I did try to mount my Type R D4 and the trim piece would not mount backwards. If mounting it backwards doesn't do anything performance enhancing I won't be mounting that way. Thanks for your imput.

I did it in my 4th order box so I can smell the coils if they start to get hot. 

Cool. That's what I thought but wasn't sure. I haven't tried to inverted my BL but I did try to mount my Type R D4 and the trim piece would not mount backwards. If mounting it backwards doesn't do anything performance enhancing I won't be mounting that way. Thanks for your imput.

buddy has it for his two 12inch bl's look sweet! 

I've seen some configured where they share a common chamber and use a push pull style configuration. Most of the time these have been in sealed configurations and I've never been able to quite understand the concept completely. However, I have also seen same style configuration except the inversed subs are phased opposite in a ported enclosure. I always assumed mostly cosmetic myself as well. 

If you have two subs in an install and one is inverted and the other is not then the polarity on one of the subs has to be reversed so they are both acoustically in-phase with each other and pressuring the cabin at the same time. If two subs are installed and they are both inverted, then the polarity needs to be reversed IF AND ONLY IF that keeps them in relative phas to the rest of the system. Really you should always check phase and verify if being wired in-phase or out of phase places the subwoofers in relative phase to the rest of the system. The only time the inverted sub MUST be wired out of phase is if there is two or more subs in the system and not all of them are inverted.

 

Push-pull mounting in a common chamber cancels even order harmonics produced by the subwoofers since the asymmetry in the motion of the cone between the two subs should be more or less equal but opposite. Unless you are talking about isobarically mounted subwoofers, which is another can of worms.

If you have two subs in an install and one is inverted and the other is not then the polarity on one of the subs has to be reversed so they are both acoustically in-phase with each other and pressuring the cabin at the same time. If two subs are installed and they are both inverted, then the polarity needs to be reversed IF AND ONLY IF that keeps them in relative phas to the rest of the system. Really you should always check phase and verify if being wired in-phase or out of phase places the subwoofers in relative phase to the rest of the system. The only time the inverted sub MUST be wired out of phase is if there is two or more subs in the system and not all of them are inverted.

 

Push-pull mounting in a common chamber cancels even order harmonics produced by the subwoofers since the asymmetry in the motion of the cone between the two subs should be more or less equal but opposite. Unless you are talking about isobarically mounted subwoofers, which is another can of worms.

 

This is exactly what I meant. And here I was going to use a computer case reference and thought "oh hell no, they'll probably think im friggin nuts".