I am planning on building the Stage 4 in two cabinets, one with the woofer centered and close to the top, with a round port or port/tube as is the case mounted in the center below the woofer, and a nice platform stand that slopes from just below the port to the floor so everything looks nice and tidy. Then I will have a seperate cab mounted in a small sand-filled platform on top of the woofer box so the horn is fairly isolated from the woofer but still close enough so the cross-over design will work as intended. I may also angle the cabinet sides back or put a 45 degree edge on them, maybe as large as 2x2" even though diffraction is probably not an issue here I thought it might just look nice and give me some practice for future projects that will require such edge treatments. Anyways, I know that I should keep the internal volume that the woofer sees the same... anything else you would recommend given my aesthetic design goals here?

Thanks, and looking forward to building your kit and putting it through he paces... Hope you are not offended that I would like to use a port tube from parts express, even if I just use the flared end in the baffle as I think it will look nice.

Regards,

Greg Jensen

Thanks in advance for any help... first project other than single driver / open baffle... and I am math challenged.

Regards,

Greg Jensen

Here's the Helmholtz formula:

Here's a little BASIC program that will calculate the formulas for you:

10 INPUT"Enclosure Volume";VE
20 INPUT"Diameter of Port";PD
30 INPUT"Length of Port";PL
40 VB=VE*1728:PI=3.1415926535:AP=PI*((PD/2)^2):LC=PL+((8*PD)/(3*PI))
50 FR=(13548/(2*PI))*(AP/(VB*LC))^.5
60 PRINT"Fr =";FR;"Hz."
70 GOTO 10