Re: RCF L15-542 Driver replacement / substitute
Ben,
The ceramic magnet Eminence Kappa-15LFA comes pretty close to your Thiele-Small and pricing criteria, but the idea of its stamped steel frame may make you spit up in your throat a little.
For a little more money and a greater distance from your target specs, the cast frame/ceramic magnet Eminence Kappa Pro-15LF-2 is a very useful driver. It's an extremely versatile and good-performing speaker for the money, but you might have to tweak your box tuning and/or passive crossover. It depends on what you're trying to achieve with the loudspeaker when it's put back together again. Anything close from RCF or B&C is going to be pretty spendy, whether they match or not. I haven't heard an FR253 in a VERY long time, so I can't comment on system voicing or reasonable expectations.
There will be others who suggest you set the enclosures on fire because if you can't obtain genuine, identical replacement components, there's no point in carrying on. I suppose -- if you continue to use these "hot rods" -- you should remove the EAW badges because these are now custom boxes...
Good luck with your project.
