I've started a couple of threads about my Ampeg V4B and DIY 215 project but I'm switching tracks on the cab now, so here goes another. Modeled and built a box around the MCM 2983 driver. Got the tuning right, and it sounded OK, but I wasn't happy with the mids and certainly not with the efficiency. New design parameters: 215, don't care about size or weight (within reason) 5-string friendly with some action below 40Hz, preferably usable down to 31 Hz Old-school tone and appearance to go with the V4B Enough efficiency to make this cab/head combo a viable alternative to my SVT/410 rig Almost danced a jig when I came across the spec's to the (discontinued, I know) E-140! Fs of 32 Hz, 100dB sensitivity and (unfortunately) a whopping 10.5 cu ft Vas. Aluminum dust cap and, according to many, among the best-sounding speakers for bass guitar. So, if I tune a 6 cu ft chamber for each driver at 35Hz, I'll get a -10 dB point of 31 Hz. I don't think my V4B is going to be getting much over 150 watts (correct me if I'm wrong). Excursion is safe up to that figure. Anybody got any comments, criticisms, etc?