I want to build a pair of line arrays using 16/18 4" full-range drivers per side split into two stacked cabinets with 8/9 drivers each. For the cabinets I am using VERY well damped sono tubes. The baffle is an 8" wide 34” L x 3/4" maple board bolted through the tube to a piece of Baltic birch plywood of the same dimensions so that together squeeze the tube to create an 8" wide flat front. I'm thinking of capping the top and bottoms of the tubes with 1” – 1 ½”corian.

This is my first DIY speaker project so a little guidance to the right path would be very welcome.

I ran the T&S parameters. Through an on-line cabinet calculator and got the following.

Butterworth B4

Vas = 0.11 ft^3

fs = 120 Hz

Qts = 0.63

D = 4 in

Dimensions

Vb = 0.25 ft^3

= L x W x H

f3 = 77.1 Hz

fb = 77.1 Hz

Dv = 1 in

Lv = 0.68 in

Do these numbers scale?

In other words can I just divide the total volume of the tube by the total number of drivers?

If so I get the number .25ft^3 for each driver and the cabinet is the right size.

Can I scale up the port to a single port per cabinet? Where should I place the port?

Does the f3 and fb = 77.1 Hz mean I can expect the finish product to be close to this as a low-end cutoff point?

Am I hopelessly lost?