Differences between small vs. large mid driver

I think the issues that Nighthawk and Sean raise are very cogent. Speaker design and building is a craft of tradeoffs. Do you push a driver a bit out of its optimal zone, or introduce an additional driver with the added complexity of dispersion characteristics and crossover? Pick your poison.

I used to be a stauch 3 way guy. Now, my tastes lean towards the two way, due to its inherent simplicity. Do believe anyone who tells you that it is night and day easier to build a good two way than a good three way ala the crossover. Of course, Bud Fried will tell you that the series crossover makes As Nighthawk pointed out, my Coincidents go down to about 40 something Hz, filled in by a subwoofer on the bottom for that last octave or so.

Eldartford, 600 Hz for a woofer has been fine for many in the history of audio. However, many do try to keep a crossover out of the midrange, and 600 Hz is a frequency that most people can hear loud and clear. My preference is to stay far away from that as a crossover point. The three way Frieds we'll be selling cross the 8" to the 6.5" at 200 Hz, and the 6.5" to the tweeter at 2700 Hz.

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.