About the JBLs, they probably were custom made. They surely are not that accurate and they probably don't efficiently reproduce below 50 Hz. I wouldn't recommend them.\n\nFIY, here is a link to a JBL library. This link also covers some of vintage Altec products as well. The names Altec and JBL are somehow related as Altec had bought the Lansing Manufacturing Company which had financial difficulties in 1941. But in 1946, James Bullough Lansing left Altec on the day his contract expired and his company was given a new name, the James B. Lansing Sound Inc. Eventually, it became shortened to JBL.\n\nJames Lansing was noted as an innovative engineer, but a poor businessman. As a result of deteriorating business conditions and personal problems, he took his own life by hanging himself in his home in San Marcos on September 24, 1949.\n\nhttp:\/\/www.lansingheritage.org\/html\/jbl\/jbl.htm\n\nI'm definitely not interested in those, lol. That's why I put it here. It's not often you see a speaker claiming 109 dB efficiency.