I'd like to convert an old pair of speakers to Two Pis. The box size is ~5000 cubic inches - between the regular and tower two pi boxes. Is there a tool to calculate whether there is a valid alignment at that size? Or are the two proper alignments only available at the regular and tower box sizes?

thanks,

Brian

Here's a little BASIC program that will calculate the formulas for you, if you can still find an old BASIC interpreter around somewhere.

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