Quote Originally Posted by VolvoHeretic View Post
Didn't I read somewhere that the driver should be something like 1/3 down from the top? and if so with a known front baffle width and 38" speaker placement, it should be easy to figure out height and depth?
Correct, the two specific offset driver dims are L*0.21 for 1/4 WL and L*0.349 for 1/3 WL, but in general for smoothest overall performance, both it and the vent should be at an odd harmonic, though as shown for the 1/3, the vent shifts it down some, but once damped, there's no audible difference between them and frankly, I always recommend L*0.4 when appropriate as it makes the cab taller, ergo more vent damping. When I do certain designs, I use a proprietary formula that takes all three dims into account to reduce the amount of damping to a minimum, to the point where so many folks were removing most of it that I quit recommending any, just 'damp to taste'.

GM