What makes an expensive speaker expensive

I think the quality-price issue also arises at entry level. For example,  consider the Vandersteen Classics (specifically 1ci) and Totem Arros. They're about the same price and both are well regarded in the forums. The Vandersteen's have survived longer, so they can be said to have stood the test of time.

Yet the Vandersteen's don't have expensive parts as far as I can tell. The Arros do - the interlocking cabinet, the veneer both inside and out, the crossover and the borosilicate  damping.

On the other hand, the Vandersteen's don't need most of the expensive materials because they've done away with the cabinet. (Hard not to be impressed with the application of  Occam's Razor).

Vandersteen's claim to fame is their first order crossover providing time and phase accuracy. Yet the Totem Arro's also claim to be phase coherent (which I thought wasn't possible with a 2nd order crossover?).

How is the price similarity explained? I guess because the sound quality is on an equal plane

The "exotic" cone materials mentioned break up as well, perhaps not as prominently in their used audio band, but beyond that could be another story, and one that requires its measures. Certainly what matters here is the nature of their break ups. The tonal qualities, as highlighted by charles1dad, is also affected through the use of different cone materials - surely an important parameter? The associated use of typically butyl rubber surrounds for such (usually midrange) drivers also comes to mind, a material which high damping properties to my ears can quench some of the "life" of the sound. It's not only the use of cone material and surround ditto (and T/S data), but the sheer radiation area of the cone is also of significance. I've never quite fancied the sound of smaller mids drivers below 6" as I often find them to lack substance and fullness. As Mr. Ebaen says in his review of the WLM Diva's:

"10-inch paper cones with hard cloth surrounds simply sound different than 5-inch Beryllium or ceramic cones that are hung off loose butyl rubber. The former are more natural, relaxed and full to my ears. In turn, they're not as overtly 'resolved'. The sharpness and leanness often associated with accuracy is missing.   

[...]

It's a speaker that will tweak certain people because it lacks what they consider prerequisites for a hi-end worthy design - narrow baffles, small midrange drivers, exotic diaphragms, famous tweeters. WLM gets by with apparently lesser ingredients. Still and to my ears, the end result is a more inviting, tastier dish. What that really says about current high-end hifi sensibilities you may ponder yourself in some spare time. "

http://www.6moons.com/audioreviews/wlm/divamonitor_4.html

Indeed I'd go so far to say that a +12" driver, with paper cone and cloth surround, is a necessity for the required energy in the lower mids and upper bass, but I gather that's another story.

Jim, let me take a stab at the Vandy 1's vs Totem.  For this price range Richard is using pretty expensive parts under those covers.  That's been his whole deal starting with the 2's many years ago.  The cones and drivers are derived from his more expensive speakers since he came out with Treo's on up.  The 1's also got better drivers and keep getting them as he keeps upgrading.  He also does a ton of listening and choses the best sounding boards and components for the price of the speakers.  

The 1's are not the same crossover set up at his other speakers though. That said, for the price I think they are amazing. I heard those Totems recently here in CT and felt they were very good speakers in this price range also.  Plenty of good choices.   

Thanks ctsooner that is interesting & helpful.

To vander off topic (get it, vander instead of wander ), while I admire and appreciate the thoughtfulness put into the Vandersteen 1ci's and other vandersteen models, the sweet spot is too small (something like a square foot). You move a little bit, or there is more than one person listening, or there is a slight mis-measurement and the benefits are lost.