[morzh]

I am sure you could find a similar Philco speaker if there is no original anywhere now.
As for how it is done, as I remember 116, the field coil is not the only filter coil in there but it is through-feed, so it is used to drop some voltage.

So,

I only yesterday answered someone about how to do exactly that in a thread - look by the keywords, otherwise I would have to repeat myself.

Basically,

You need to replace the field coil with an equal resistance with appropriate power rating which you hacve to calculate, and then see if your voice coil impedance matches and if not - pick another output transformer.