If i use a flared areo port in a 2.5^3ft box would one four inch be alright that would be 12.5 square inches port area. Box will be for 4 8" subs

I had two 3 inch aero ports on two 10's (basically the same as one 4 inch) and it didn't seem like enough port to me.

You have almost the same cone area as two 12's. Since you posted this in the SPL area I would recommend two four inch ports. If you are asking more for SQ I would say you are fine with one.

Edited January 22, 200916 yr by banginAltima

I think you would want at least two 4" aeros.

IMO You need atleast 2 4" areo's ports I ran two on my 4 L5 8's and had TONS of port noise... (the L5's have more surface area than a regular 8 though) it was 2.5cubes tuned 28hz

thanks guys