Differences between small vs. large mid driver

While I agree with the gist of the above, I beg to differ slightly. Since I listen to large orchestral music, I need authority, dynamics -- the ability to excite lots of air.
So, for the ~100->8-10kHz part I would use a wide-range 8-12" (supravox, lowther, goodmans, etc). The trade-off here is beaming...
For the upper range, a super tweat to over 25kHz. The trade-off here is the difficulty to align the acoustic centres of tweet & wide-range (at 8kHz the lambda is very small => the margin of error is high).
For the lower register:
At least one 15" per channel for bass (two for open baffle).
At least one 18/24" per channel for 20-45Hz. The trade off here is cost and cost (cost of drivers, cost of amplification).

Overall, such a construction ideally needs a minimum of three amp channels per side. Passive filter for crossing to tweet; Leave the wide-range free on top, cut it with a soft LPin the bottom. Active or PLL for the rest.

Wishfull thinking, eh?

I think your opinions are very good, Gregm. I also am particularly enchanted with the sound of the Lowthers, and should have mine mounted in a cabinets I am building within a month or so. The speakers that Audio Note Kondo Japan was running at HE2004 were very much as you described, and they sounded fabulous to my ears.

You may or may not know that Bud Fried was the original importer of Lowther (also true of Quad), and when I spoke to him recently about speaker projects I was working on for fun, I mentioned them. I expected him to tear them up, but he recalled an anecdote from long ago where a dear friend of his bought some very expensive AR speakers, and they both found out that they could just not do justice to the piano, which the Lowthers had always handled with aplomb.

Piano is PARTICULARLY important to Bud, as his wife Jane is a pianist. He still holds the Lowthers in extremely high regard. Believe me, if Bud doesn't rip something, it's a compliment. If he praises it, it's more than a tribute to how good a component actually is.

Trelja...The system you describe can cross over to the "Midrange" driver at 200 Hz because it is a 6.5 inch ubit, which I would not describe as a midrange driver. I would describe the system as a 8 inch subwoofer that can be crossed over at 200 Hz because it is so small, plus a two-way system. Not a bad idea. I have advocated running the subwoofer up to a higher than usual crossover frequency if it can hack it. Takes the heavy lifting out of the main system.

One reason to keep the woofer/midrange crossover higher than what you suggest is the electrical values of crossover network components necessary for subwoofer-like frequencies. Expensive, and bulky.

Eldartford, may I direct you to the comment which Andy2 makes in the heading of this thread? The statement is that "expensive" speakers tend to use smaller midrange drivers.

By the way, why don't you feel a 6.5" driver is not a midrange? Anyway, you could cross a 5.25" or 4" at 200 Hz without issue.

While I am one of the biggest audio cheapskates here, I have difficulty in grasping how 150 mF of capacitance and 3.0 mH of inductance (200 Hz crossover) is too expensive for audio. Particularly, expensive speakers. This when for the same money (less than $200 for topflight components - 10 gauge North Creek coils and their better caps), an interconnect would never even be considered a serious cable.

For me, it's a no brainer sticking this kind of money into a crossover. It makes more sense to me than cable, shelves, isolation devices, tweaks, etc. But, then I am a speaker guy...

Now, bulky IS where I will agree with you. I personally have had serious concerns in putting components this large in a Transmission Line, but for the sealed or ported speaker with the kind of size that is required to run this type of crossover, I believe could site them fine.

Trelja...I read Andy2 comment to be saying that expensive systems have midrange drivers (suitably small) whereas less expensive speakers are 2-way.

I think that a 6.5 inch driver will have some problems in the 1500 to 3000 Hz range. (Check Nighthawk). Good tweeters cannot be crossed over low enough to avoid this.

Agree that a 4-5 inch driver can go well below 200 Hz...the 5 inch woofers (and I use that term loosely) in my MTM Dynaudios put out surprisingly low tones, but not very loud. These drivers, with 3 inch voice coils, (almost as large as the moving cone) do make darned good midranges, and I used the Dynaudios that way in a biamped system for a few years. I now have MG1.6 Maggies doing what the Dynaudios used to do.

$200 is dead on for cost of the 200Hz crossover parts (I know because I bought three sets). That's a fair chunk of change for parts that the typical consumer will never see and doesn't appreciate.