[Arran]

Mike;
If you are thinking of a dynamic speaker like most radios use to this day, then you would be quite correct about needing a transformer. I have a speaker from a Radiola 33 where someone fitted a 5'' P.M dynamic inside, and it has an output transformer fitted, so either the original speaker failed, or they just decided to re-use the cabinet. I also have a Radiola 100A, with a broken cabinet, that I picked up for the 8'' speaker inside for the Radiola 33speaker, and it's a high impedance cone speaker, with a tar filled paper cap and choke in series with the voice coil. The A.K speakers would be similar, either the horn, or cone speakers, without the chole and capacitor. https://antiqueradios.com/forums/viewtopic.php?t=444395
Regards
Arran