This is an item to discuss speakers that are accurate to the timbre of musical instruments. My JBL C51 Apollos are truly startlingly realistic in the mid range, a piano sounds like a piano and a cello sounds like a cello. They don't do everything well, they roll off at the bottom around 50 hz and at the top around 15,000 and I thick they are exaggerated in the upper bass/lower mid range, but for the timbre of certain acoustic instruments they are great.
That's exactly the way I would describe my current speakers (Wharfedale W60E's - From around '71-'73 - Similar in size, shape, and price to a Large Advent or AR-3a, - 3-way acoustic-suspension design - front-loaded drivers - acoustically-isolated mid-woofer (The tweeter is isolated as well, I believe) - 12.5" woofer [cone - paper-pulp, I think - reversed hard-rubber surrounds], 5" mid-woofer [paper-pulp, I guess - with a kind of gauze material used for the surrounds], dome tweeter [about an inch - made from that purple material that Wharfedale used], attenuators on the back of the cabs for adjusting mid-woofer and tweeter levels (extremely-useful), power-handling is 50w RMS (per-speaker).
I've been using these speakers for the last 11 months or so, and I'm really digging them. Like you said, a piano is a piano, a sax sounds like a sax (and sounds like THAT sax in the recording would have sounded if you were there in the studio listening to them record it). They're especially-good with stringed instruments like cellos and violas. And drums are always punchy and lively with plenty of bass and yet still accurate-sounding. And they're one of the best I've heard with the human voice - Outstanding vocal reproduction. The overall sound is a warm, smooth, "east-coast" sort of sound. And I listen with them pretty-close - maybe 6-7 feet (They're actually at their best when they're placed in corners), so I'm not getting the most out of them at the moment. Their strength is in their midwoofers. I don't know how this one differs from earlier Wharfedale designs, but it's a fantastic-sounding mid-woofer. The tweeter is great. It's lively, but not overly-pristine - and certainly not as rolled-off as the mid '60's Wharfedale tweeters. The woofer does it's job well. I've heard more-accurate woofers, but these produce tight, smooth bass that has a bounce to it (and I'm not talking about a "Thrusters" bounce) that works extremely-well for '60's and '70's classic rock and pop, not to mention jazz, funk, and fusion (I should mention that the woofer cones are pretty-stiff and they really don't move much, even under higher-volume conditions with bass-heavy music). These speakers are very-versatile and with the right amp or receiver can handle modern rock and even a little rap (I listen to quite a bit of old-school 80's and early-mid '90's rap). They perform very-well with classical and 50's and 60's jazz, especially if you give it some volume. I would call it a warmly-accurate sound. And I've gotten the best response out of them with low to mid-powered early '70's SS receivers (although you should get great results with a 25w-50w tube amp or receiver). These speakers LOVE a warm and lively-sounding power source (amp OR receiver). They totally come alive.
The cabinets are extremely-well-made. Thick walnut veneers, solid-wood trim, and built like bomb shelters. Great cabs for Econowaving too. Even though I'm pretty-sure these are not sand-filled like the earlier models, they don't resonate much at all - which is great for my situation because my apartment isn't exactly acoustically-isolated from the people upstairs, and plus the walls can rattle a lot with other speakers - I don't have that problem with these.
One problem I've encountered since I got these is that they reveal any flaws that a recording might have, whether it's a bad digital transfer, or some surface noise on a record, or a flaw in the recording itself - if something's wrong, these speakers will let you know about it (Not a half-hour ago, I had started listening to a "lossless" digital file of the DCC CD version of "Jim Croce - 24-Karat Gold In A Bottle" and there's a very-light digital distortion over the entire rip - Drag, dude - *EDIT* - Turns out that the distortion I was hearing was due to the Rotel receiver I was using at the time - It needed a cleaning - The Jim Croce recording is fine, and that's a good thing because I really dig that one).
I've read where a few snobbos here and there have called this a "mid-fi" speaker, but I'm getting some excellent sound from mine right now, and for the prices these are going for these days, these are damn-fine speakers (and beautiful-looking as well). These are keepers (Picture is not of mine - I can't upload digital pictures right now so I got this picture off da' Bay)
http://www.audiokarma.org/forums/attachment.php?attachmentid=179571&stc=1&d=1258299036
http://www.audiokarma.org/forums/attachment.php?attachmentid=179572&stc=1&d=1258299400
http://www.audiokarma.org/forums/attachment.php?attachmentid=179573&stc=1&d=1258299705
The Acoustic Research AR3a is another speaker that matches the description you gave in the first post. They're a 3-way acoustic-suspension design using one 12" woofer (I think it's actually 11" though) and a dome-style midrange and high-end drivers).
And someone recently-mentioned about Splendor speakers (I think that's the name). They're supposed to fit that bill perfectly.
Also, Bozaks are known to be timbrally-accurate. And the older Wharfedales are also good for that. These kinds of speakers don't have the same kind of so-called "accurate" sound that modern speakers have (and not everybody likes the rolled-off highs), but they reproduce voices and instruments VERY-well, and were designed to reproduce things like classical music as you would hear it in a concert hall - The rolled-off highs being part of the design).
