Fostex recommended BR Port Adjustments?

[OTMOPO3OK]

Hi everyone,
I'm making a ML TL using Martin J. King's desing for 207E and i also need to make center channel and 2 sets of surrounds.
To keep my costs down i decided to go with FE127E for smaller speakers and with the recommended by Fostex BR box. Now i've noticed that the plans even mention the location of the port and driver relative to the sides. So i started wondering that maybe their is some quater-wave theory to this. Or are they designed just as regular BR?
What i would like to do is to reconfigure the ports so that they are rectangular and on both sides of the driver. (make it more symmetric - point source like). can i just do that or is there some standing wave theory involved to the location of the port and driver.

PS. Also since in HT center channel is very important should i make just the center speaker using 167E or is 127E enough. (167 is twice $ of the 127)
Thanks a lot for the explanation.

[Timn8ter]

I doubt there is enough length or cross sectional area to set up any QW action in the Fostex designs but it wouldn't surprise me if there was method to the driver and port placement. The double-bass is a mechanical low pass filter and the other design is a standard BR.
What you've described in an Onken enclosure. Just do a search on this forum for Onken.
Since 60%+ of the information in HT is handled by the center don't skimp if you're going to have one. The FE127E is a wonderful driver but it's not going to keep pace with the rest of your system during loud movie passages and you could easily damage them.

[OTMOPO3OK]

Thank you.
I decided to go with 167E for the center and 127e for surrounds.Now the thing that bothers me is that i modeled suggested cab and it's tuned to roughly 100hz. But the driver goes to 50hz so how can i take advantage of that without going into TL design. The bigger i make the box the F3 doesn't go down even if i have port tuned to 56hz and 20l box the F3 is still 92hz. How come? is something wrong with the modelling soft or me?
BTW i tried numerous programs: BassBox Pro, MathCAD Ported Worksheet by M.King,SubSim, WinISD. It seems like every program gives different results. They all use different formulas i guess, so now i'm just very confused. Any help?

[Timn8ter]

I don't know why you get the results you do. I can tell you that a BR center channel for the Fostex FE167E will have internal dimensions of 20" x 12" x 7" and a three inch diameter port tube 3 inches long. This will give you a tuning frequency of 59Hz and F3 of 55Hz which should be more than enough for a center channel since your sub will most likely come in at 80Hz+.

[OTMOPO3OK]

WOW! Thanks for such quick answer and the calculations. Can i ask which soft you prefer yourself?

[Timn8ter]

I like LspCAD and Martin's MathCAD worksheets. I use WinISD as a cross-reference.
Glad I could help.