You might be able to find a donor pair. If not match to Seas or similar. The specs for the tweeter can be found and would be a matter of matching but with 4 tweeters per pair I would look for a donor pair.
Mirage M-3si Replacement Tweeters
Looking to replace the four tweeters on the M-3si’s I purchased in 1993.
These are powered by Audio Research D400 amp and Audio Research LS2B pre-amp.
I am hopeful there are other Mirage owners that have solved this problem since the company is out of business.
Suggestions?