I bought this extension speaker because it was unusual. At nearly 19" square, it really is huge and could easily accommodate a fifteen inch circular driver unit. As luck would have it the original paper-coned moving iron unit had long since gone and had been replaced with a puny 6 inch speaker from a post war valve radio.
I was wondering what to do about it when the phone rang and an old customer asked me if I wanted a hi-fi cassette deck. I declined his kind offer because of shortage of space and he went on to say he also had a small amplifier and single loudspeaker. Thinking these may come in useful I accepted and was a bit surprised later that day when Mr.Orr appeared with the tiny amplifier but a huge speaker enclosure.
When I looked inside the enclosure there was a very large oval driver around 14 inches by 10 inches together with two tweeters. Exactly what was required to update the old Celestion!
As there was a lull in the repair business and I quite fancied hearing what then Celestion box sounded like I set to work and transplanted the large oval and the tweeters together with their crossover unit into the 1925 mahogany box. Afer lots of hacking and sawing of chipboard to mount the three speakers and a spot of soldering it was complete and I tried it on my son's hi-fi.
The sound quality was superb.