I just ordered the 1503 last night, and the loudspeaker cookbook should be here any day. Box: sealed (mdf) Qtc estimate: .62-.63 Vb calculations for .62 Qtc: 2466 in^3 (40.392 liters) Box ext. vol.: 16.5 x 16.5 x 16.5in Box int. vol.: 15 x 15 x 15in = 3,375in^3 Net Int. vol = (Int. vol.) - (Motor Struct.) - (bracing) - (flange) Net Int. vol = (3,375) - (415) - (337.5) -(366) = 2,256 in^3 (around .63) I think I over compensated for the amount of bracing I will use, so I should be right around .62. I am going to get the bfd, just looking for a cheap one on ebay, and a QSC rmx 850 or 1400. I know I'll learn a little more when I read the loudspeaker cookbook. I just got a couple more questions. 1. Do you think I should make the baffle thicker than 1.5 in MDF 2. What do you guys think? Thanks!