2 questions for guys.

[Chaosgrunt]

First off, how do you know the cubic feet of a transmission line box? Does the box's volume end at the first curve of the transmission line, then the port volume starts after that?

2nd question. Where would be a good starting point for learning about the physics behind subwoofers in boxes? I wanna be able to calculate the peak of the box, excluding the cars resonant frequencies, and be able to graph the boxes output in db's at certain frequencies. And not to mention being able to understand it all. Is there some book or guide to get me started on this subject? I know there is software that does this already and its great, but I want to understand it all as well.

Thanks fellas.

[bassface]

On this site somewhere is a t-line tutorial. It will tell you everthing you need to know. Actually its the first listing under subwoofer/enclosure section.

[john253a]

The basics for 1/4 and 1/2 wave t-line are

(1130ft/hz)/wave lengh = port length

R x R x (22/7) x nubber of drivers= port area

(measured from surround centre to sub centre, this is also very close to cutout measurements)

Example 2x10" subs in 1/4 wave box with fs 35

(1130/35)/4= 8.071ft x 12= 98.85" port length

4.75 x 4.75 x (22/7) x 2 = 142sq" of port

Edit

Now I could be out a bit as I haven't done one for a while

But the post your after is in the sticky section under t-line

[Chaosgrunt]

Oh ok I see. Now what about the second question?