First Order Crossovers: Pros and Cons

Cdc -- there may be numerous advantages to multi-driver spkrs but spl is not necessarily one of them (think of those 22.000 gauss Lowthers with a front horn).

I love wide-range drivers. Single wide-range drivers are actually rare; remember the whizzers on most such drive units. Limited frequency range, beaming, dispersion, IM, (response peaks & valleys)... are some of the most annoying (to me) problems. {BTW, you DO use a circuit on the Jordan & it actually sounds good}.

BUT, a single wide-range unit has immediacy, reasonable response in a critical region (200-4kHz, most will do 8kHz for you, some will actually hit F6 @ 20kHz withOUT a whizzer!!), phase & the like are out... it's marvellous. Extension can be had using a supertweet (not easy to match) and, better still, using a stereo subwoof.
Tough to beat.

Ultimately though, these are EXPENSIVE spkrs. Driver cost alone for a high level full-range biamped design can easily top $6k (that's $35-50k in commercial equivalent).

Gregm, that's interesting about the Jordans. Is this a baffle step compensation if they are not put up against the wall?
In my limited experience with single driver speakers, the biggest shortcoming IMHO, and this is highly listener dependent; is lack of detail especially in the higher frequencies. They are there but at a very low volume level. Maybe the driver jsut can't move this fast to reproduce at full volume level.
The Fostex F200A is an 8" driver which measures maybe -2dB at 20Khz. Wish I could give that a listen.

Well, a single "perfect" driver would be large in diameter so as to achieve good coupling with the air load so that it could reproduce low frequencies well. Unfortunately, that leads to problems with directivity and also possibly smearing of the high frequencies from widely spaced sources of the same signal. (Think panel speakers.)

So we'll go with a smaller driver and increase excursion. Then we start seeing problems with IM.

Since real drivers aren't perfectly stiff, they don't maintain pistonic motion at all frequencies. (Real drivers also have mass, and that changes things too.)

So, a cone driver will "want" to become a smaller cone at higher frequencies, and we start seeing breakup modes. This can be damped to some extent by the surround.

Ted Jordan explicitly allows for this behavior. He claims to control it in his drivers. But he's still using metal cones, and there's going to be a nasty breakup mode. the only question is how well controlled it is.

I suspect that some "full-range" drivers actually use these breakup modes to increase output at high frequencies and provide some impression of treble. Not what you'd call accuracy. :-)

So what's wrong with a multi-way system with drivers that are more likely to be able to display pistonic motion throughout their passband? Crossovers and the physical spacing of the drivers. This causes some problems and makes it harder to provide an accurate "re-assembly" of the waveform at your ear.

1st-order crossovers screw things up less than steeper slope crossovers, but place higher demands upon the drivers. (But still not as high as the demands upon full-range drivers.)

Physical placement is harder to cope with, but you can control some of it, particularly since we're only listening from one point at a time.

It's almost a Catch 22. Real full-range drivers have major problems. To solve those problems we use multiple drivers, which introduces other problems. I submit that the problems with multiple drivers can be solved more easily and more fully than those with full-range drivers, given the current state of technology.

(One possible solution is to use full-range drivers at very low power levels. This works with headphones, but not so well for normal speaker systems.)

There's just no free lunch. :-)

Cdc-- I only dimly remember the Jordan circuit, but it looked like a contour rather than BSC (it was across the driver -- but don't hold me on this!).

Skrivis:
Re: first order+ drivers. Why not use a wide-range drivers -- i.e. a 8" + supertweet, then a hefty subwoof. You'd have to biamp (at least) but, as you note, there's no free lunch!

Gregm> "Why not use a wide-range drivers -- i.e. a 8" + supertweet, then a hefty subwoof"

Well, an 8" driver is generally going to be getting pretty far away from a pure piston at treble frequencies.

Perhaps a smaller mid-woofer crossed at 3-4K to a tweeter, and then a woofer or sub below it, crossed at maybe 100 Hz?