Postscript: My beloved Genz Benz 410T-XB2 weighing 43Kg was getting too heavy for me. It has worked so well with upright bass that I reluctantly decided at my age that I should cease trying to lug it around. So I've built a new birch ply 4x10 cabinet along pretty much the same lines, 5 cu ft tuned to 50Hz, Eminence CH-2010 8 0hm 150w hemp cone speakers which I got for a bargain price. I contacted Eminence who were extremely helpful and assured me that the CH-2010s were indeed a very good speaker but they didn't sell enough of them to continue production. I've used the cabinet on several large gigs and I'm delighted with the performance. Upright bass is very demanding on a speaker system but, unlike some other 4x10 cabinets, it works right down to bottom E. I fitted a pocket handle into the back and with a total weight around 34Kg I can easily lift it.