Sorry for bumping an old thread.....but, the answer to the question is.......the speakers were built from 89 - 94. I bought mine in 1990 and they are still in "like new" condition, even though they were toured for 5 years.
I also have a question. I was looking at the back of my speakers, trying to find their wattage rating as I'm about to add more speakers and it says "see manual for power rating." My manual is long gone. I was wondering if anyone knows what the power rating is for these speakers? I searched the internet and found nothing. Apparently these speakers don't exist anymore because I can't even find someone with a used set for sale.