box for Pioneer TS-W306DVC

Hello,

I've got a question concerning the Pioneer TS-W306DVC sub. My sub is wired to an Alpine MRD-M301 (HU Alpine CDA9847R) and i've built an enclosure for this woofer. the size of the enclosure is about 90 liters. i planed to set this woofer in a BR enclosure, so all i need is to work a pipe in the enclosure and that's where the problem begins.

the subwoofer is placed in the middle so i thought that 2 pipes would do a better job than one because the pressure can be put out left and right from the subwoofer.

can anybody here tell me sizes etc. for the pipes (and if it's recommended to use 2 pipes anyways)? I'd really be thankfull for some help since i don't want to mess up on that one.

thanks!

Well, yeah, I've checked this section and typed in the settings of the pipe. But the problem is that those calculatings are only for one pipe but i planed to work in another one. could anybody tell me how the dimensions of the pipes would change if i used two of them?

thanks