any ideas about this lot

[j_s]

If a couple of 8s are in a box and you feed em high power then definitely use 18mm 

12mm is fine for the front mate.

In terms of how many subs you put in a box, it depends where the box is going to be, you will need to build the box to the sub manucturer's recommended size.

[theviper]

my friend is getting rid of 4 x 8 inch Rockford Fosgate which are air free if i got them and put them on the shelf would they be better then 3 x 8 inch in a box
Pete

[vr4000d]

i prefer boxed subs personally:)
if you r buying why not just get a 10 or 12?

[theviper]

i am not buying them i can have them for nothing if i want them so needed to know what is better
pete

[vr4000d]

ah ok i would still say sealed

[theviper]

cool a box it is then the last question on this the 3 subs in the box which is the best way to wire them up
do i join all 3 speakers together or wire them individual to the amp
Pete