Hello;
OK, I stand corrected. I just spent an hour trying to locate Foster on the net with no results. Foster was a manufacturer owned by I.M.C. (International Music Corp) based in texas. The CEO was what we called a loose cannon and I know they had financial troubles in the 90's. Foster however was (or is) a Japanese Company (or Corp) that was quite large. Most live music speaker cabinet manufacturers in the states used foster drivers at one time or another (except for the biggies like JBL). Frankly I'm suprised - I used foster drivers in a lot of my cabinets as did Sunn and many others. As for new diaphragms for them I believe the N27, N30 and N47 all used the same one so if you could find some of the old bullet N27 style tweets Sunn used in there horn arrays, that nobody liked, and rob them of the diaphragms you'lb be in biz. I have not found a source for second party replacements.
Don T.