I know this is an old thread, but there's some good information here. I just finished rotating the 12.5" woofer 180 degrees on one of my cabs (I did it in the other cabinet about 2 weeks ago, but I didn't get around to doing the second one until tonight). Another AK member suggested doing this so the magnets would be rotated. I don't fully-understand the reason for doing this, but it seems important (Something to do with the magnets sitting like that for all those years and settling - I guess it somehow affects the performance of the woofer - I don't know).
I like that ad info a few posts back - very-helpful to have it all in one post like that. The E series "Achromatic" speaker line is definitely a different animal than the earlier W60 and W70 models from the mid '60's, although I do think that the W60D and W70D models are of the same acoustic-suspension design as the E series. Whether they are technically a part of the "Achromatic" line or not, I don't know, but they seem to be a similar design (If the D models are front-loaded like the E's, then I would think they're basically the same).
I understand the W90 did not survive long enough to become a part of the acoustic-suspension "Achromatic" line of speakers. Different design - ported, I believe. As are the mid '60's W70, W60, and others from that era. As far as I know, these are models that were meant to be driven by low-powered tube amps, and they cannot handle anywhere near as much power as the acoustic-suspension models. Try and power those with a 150w receiver, and you will fry the tweeter in a heartbeat.
And speaking of tweeters, the E series models apparently used the same basic purple dome-tweeter as the earlier W60D (Made from mylar), but it looks a bit different on the W60E because there's less of the tweeter showing (different diffuser).
The 5" mid-woofer also looks different. I don't know much about it, except that it puts out some fantastic mids. Voices sound like voices and not RECORDED voices. And each instrument is represented very,very-naturally. I really think the mid-woofer is the strong link in the chain on the W60E. And the mid and hi attenuators on the back of the cabinet are extremely-helpful in dialing-in a great sound. These are very-versatile speakers, IMO. And with a 25w per-channel mid '70's receiver powering them, I can play anything from classical to jazz to classic rock/pop to heavy metal and even rap, and these things just keep on singing. I'm still going to try using 45w per side (with the RIGHT receiver), and see how they respond.
Like others have said, raising them helps A LOT. I have mine set up so that the mids and tweeters are aimed at my head when I'm sitting at my computer and they sound great. I wish I had more room to push them back. Corner placement is supposed to be optimum. RAISED corner placement would probably be better. And these speakers seem to sound their best when powered by a receiver or amp from the same approximate era (early to mid '70's). I tried using a more-"accurate"-sounding amp (an 45w per-channel NAD 3140 integrated amp- from '81-'83), and they sounded okay, but something wasn't right. When I switched to an early-mid '70's 25w per ch. receiver, the speakers just blossomed. Suddenly they had more-clarity, warmth, and liveliness. It's as if the speakers "woke up". There definitely seems to be a synergy happening.
Edit/11/01/09 - Right now, I'm listening to the "Rage Against The Machine" CD (S/T - debut) and the W60E's are handling things just fine. The drums and guitars sound especially-good, and the soundstage is perfect - very-deep sound to everything. It helps that this is one of the most-well-mastered CD's ever released, but these speakers do a great job with this kind of stuff. I try to avoid the super-low dub-type stuff, but for a speaker from the early '70's, the W60E can handle the rap quite well - The mid-woofer's exceptional vocal reproduction sees to that. Any new stuff that's well-mastered and not totally-brickwalled should be no problem, you get this with no ear-fatigue.