Sourcing a field coil speaker...

[titanstats]

Hi all. Recently reveneered and almost finished restoring an old Westinghouse radio that was my parent's. It looks beautiful now (covered it with Koa wood, kept it kinda blonde), but I'm having trouble finding a speaker for it. It used a 6" field coil speaker originally, that I cleverly removed when I was about 16 (and tried to restore it for the 1st time) because the cone had a rip in it.

Question is, when looking for a speaker, what matters? I know little about these types of speakers -- anything that I have to consider? Is it possible to replace it with a more contemporary fixed-magnet speaker? Seems that 6" field coils are a bit of a bugger to find...wish I'd known that way back when I was 16!

Thanks, all.