.....maybe a third box wasn't an attractive option. So they then developed JR150.
I have a selection of original documentation here which I believe date from around 1978. The 150s were reviewed favourably in Hifi News in October 1979. In sales literature, JR claimed a frequency response for the 149s from 40hz up and for the 'Super - Woofer' (note it isn't called a sub) down to 30hz. The magazine review has the response of the 150s as 40hz up same as the 149s but concludes 'the 150 offers more output, a smoother and slightly extended response, with improved transient performance, particularly in the bass.'
There were (I think) 3 versions of the sub. One was taller and smaller diameter and possibly had a built in amp but I have no info on that. The others looked the same but the arrangement at the base came in 2 versions. The first (possibly earliest) had castors and the driver mounted in the bottom face with a port adjacent so firing at the floor with sound 'escaping' via the gap created by the castors. There was no reason for acoustic foam on this other than appearance matching the 149s. The second had a 2nd tier base seperated by short dowels, so the driver and port were firing straight at a board mounted on the castors with the sound escaping between the 2 boards (and therefore through the acoustic foam). I can't recall which version Radine preferred when he tried them both with his 149s after completing the refurb. Perhaps he will chip in.
The dimension are 47cm high x 51cm dia and they weighed 17.5Kgs.
There were 2 varieties of controller. The LPA (low pass amplifier) was used with speaker cable connections and output 25 watts rms - hardly floor shaking
. The EXA (electronic crossover amplified system) was used with pre outs and had 60 watts. The sets Radine and I had (now sold on) were both LPA units.
If 30hz is sufficient for organ music, I suppose the Super-Woofer could also be used with 150s but a small modern sub would probably be superior sonically.
Toto Man and I should get our fingers out and fit the Monacor drivers to our 150s!
Jim