OK, so I found and this time acquired, another pair of ALTEC 3000 tweeters. They are the later "H" version of the tweeter with DCR measurements of 9.3 and 9.9 ohms. I also acquired the matching N3000-F crossovers. However, I would prefer not to use the crossovers for several reasons including the possibility that they may be out of spec. Date codes indicate both tweeters and crossovers were manufactured in 1969 which still makes them almost 50(!) years old.

My dilemma now is what capacitor value do I chose to high-pass the tweeters? This version of the tweeter is "rated" at 8 ohms but the DCR measurements may indicate otherwise. In my google searches for information, I came across a post from a recognized ALTEC expert. He wrote that while they are true 8 ohm tweeters they typically measure higher DCR readings. If I understand it correctly, the impedance that matters is the one at the crossover frequency, less so the actual DCR measurement.

So, what tweeter impedance do I use for the crossover calculator to get the cap value? 8 ohms, 16 ohms or compromise (split the difference) and use 12 ohms? Since I have found ALTEC 3000 tweeters output to be a bit weak, as compared to my Jensen RP302s, **I need to balance getting maximum output from the tweeter vs. making sure they are well protected because they are so fragile (and no longer repairable). ** I found a post from Joe Roberts and he recommended a 1.5 or 2.0uf cap. Since 1.5 is safer, I could start with that (or even lower) and go from there. Thanks.

Gerry