Venki, I am no good at maths so figures have little meaning for me. Adding up even single digit numbers sometimes cause me problems like adding 8 and 7. Mine is purely a ear and sight method using a tone generator (if there is no tone generator then single bass notes from you tube will suffice) and ball park figure for the size of the box. Each pair of boxes is tuned for that particular room and taking into consideration exactly where the box is going to be placed since bass extension and perceived loudness is greatly dependent on room acoustics and final placement. I am a hands on type of guy and hence had to device methods to circumvent the need for calculations, since finally it is the sound for individual pair of ears that matter. Tastes vary too as regards the amount of bass and there are low bass junkies
for whom even these pair of earphones are found to be inadequate. I am like WTF; how could anyone tolerate more bass than these earphones since these things are very loud even at extreme low frequencies of 18 hertz. http://www.sony.co.in/product/mdr-xb90ex
Would love to meet you at the next meet.