B139 Substitutes

Nominal 10"/250 mm Drivers* similar to B139 (sorted by price): The line was originally designed for a Kef B139 or a Radford BD25. Both have Fs of 25 Hz. The B139 has a Vas of 164 liters (9,990 cu in), a Qt of 0.37, Qe 0.4, Qm 5.5. So one approach to the problem is to look for something similar. Augsburger, in Loudspeakers on Damped Pipes, says that cone area is actually unimportant. In this case you could spread for search to larger drivers and smaller drivers, and multiple drivers.

Vendor Model Material Qts Vas (liters) Fs Hz Znom (Ohms) dB/ 2.83V/ m Xmax (mm) Kef B139 -- Target specs Al foil, expanded plastic form core 0.35 164 25.0 8 96/11 V/m 6.00 Peerless 850146 Sandwich 0.35 144 22.0 8 88 9.00 Volt B250.8 Paper 0.30 126 24.0 8 89 5.50 Lambda 10001-PFPMF-6AF PP 0.37 90 20.5 6 89 14.00 Morel MW1075 DPC 0.44 155 25.0 8 89 4.25 Morel MW1077 DPC 0.44 155 28.0 8 90 4.25 Hi-Vi F10 K.paper 0.38 98 28.0 8 89 6.50 Vifa M26WR-09-08 Paper 0.32 130 28.0 8 89 6.50

*From the drivers listed at the LDSG (9-sept-1999 & 28-jan-2001). Much more driver information is available there. [ <-- Back to TL Speakers | Drivers | Kef B139 ]