20+ years old, use ATC SM75-150 3" mid driver and an ATC SB75-234SC 9" woofer but I am not sure of the tweeter. These would probably be similar to an older (non SL version) of the ATC SCM50. If you just bought them then listen carefully for any "buzz" from the woofers (in case they were overdriven) - Alnico is rarely used these days (costly).