Canton CT-2000

I have a pair of these and one has a bass driver that needs to be replaced.  Canton no longer supports these as they are 35+ years old.  Does anyone know if other Canton models used the same or an equivalent driver?  Also I spoke with a guy in Germany who has a pair and drivers in his were replaced with drivers from another German company Visaton but he could not give me any details.  Might anyone know that info?  I intend to contact Visaton and see if they might know.