Hi Lew, just taking a break from building shelving and thought I'd take a look. From the grapevine I've heard in fact the precise opposite concerning the AMT4's (these are the "smallest" stand-mounters) woofer/tweeter integration, and this is how I hear it (it's the larger AMT1s which had the integration problem). Several well-heeled audiophiles visiting my various soundrooms have always been wowed by these specific speakers again and again, as opposed to the rest of the list which leaves them less impressed all taken in all, as the ESS garner universal/unanimous approval, while the rest get raves from some and not from others, more of a mixed bag of reactions. A simple Googling reveals many fans still of these speakers, who won't let them go for anything, even while owning highly-regarded current designs. Evidently synergies exist.
Things have changed over the years with respect to cabling (I use a mix of Petras for interconnects and solid-core for speaker wire, both very smooth and aggression-free), and set-up (specialized metal stands which I use with my AMT4s, Tiptoes and so on), which might account for the lack of annoying colourations, and their existence back when. Of course, some amps excite the tweeters more than others, as with all speakers, so I go with what works, again as with all speakers.
The Heils and various spin-offs are currently being used in a rather large variety of pricey high-end speakers still today (especially in Europe), and their specs are magnificent: a 97-db efficient driver capable of taking up to 300 watts without distortion and with a frequency range going from a typical 1200 hz (sometimes as low as 800) up into the stratosphere. The trick is implementation, as always. As always with most things, YMMV.
That said, I prefer a variety of other speakers as far as PRaT/musicality goes, which is why the AMT's don't simply stay in the system, perhaps there is a dissociation between the tweeters and woofers being revealed here. But, I've never replaced the elements in the crossover, they sound so good, we'll what happens when I do. Others are not so sensitive to PRaT/timing issues, which explains the more ambivalent reactions re. the other speakers on my list, who prefer the smooth raw detail/information and beautiful string sounds of the AMTs (no other speaker in my experience plays guitar playing like the Heils, for string fans). I do prefer the vintage Sony amps for the Heils, or the Pierre Amp which is ultra-smooth/velvety, which are both tubey-sounding. The Heils are ultra-revealing of any hardness or brightness in an amp, or wiring. Tubes and the Heils don't mix so well, as then there is a glassy colouration, so far in my experience, though I'll try the Leak again with the Heils at some point.
So far, the Technics SB-4s (!!) are leading the charge, the Spendors go downstairs, the ESS go up next, I'll report on this between shelf-building.
