My "woofer tester" is currently not running on the pc, but I had measured these back some time when everything worked with my woofer tester, and found out they are identical to the Altec 414 specs.

From my memory: fs= 30hz, qts = .35 eff = 96db Vas = fuzzy memory says 10 to 20 cubic ft.

Sorry I can't remember more than that. I do remember these measured same as Altec 414's as I measured the 414's and the (Altec/Utah???)'s at the same time and were identical. The 414's of course had cast frames and alnico magnets, the clones are (40 - 60 oz/ceramic) magnets, stamped frames.

I don't frequent the Altec website much anymore so unsure, I have become a JBL junkie!

Ron