The Shure V15 V with a Jico SAS/B stylus VS The Soundsmith Hyperion MR and Lyra Atlas SL

@mijostyn 

I do know and understand that stuff, pretty much like the back of my hand.  Absolutely right, subwoofers should be put to work on long wavelengths, which often will be longer than the listening room.  They will excite room resonances and one benefit of having multiple subs is that they average out these resonances a bit.

Now are you saying that the longest distance between any two of your subs is four feet?  I am particularly familiar with the Duntech Sovereign where the blurb says it is "acknowledged by experts as the finest speaker in the world, certainly the most accurate".  Each speaker has seven drivers in a floor to ceiling D'Appolito arrangement, which puts 12" bass drivers near the floor and ceiling.  Base is quoted as down to 27-Hz within 2-dB.  A huge amount of effort was put into time aligning the seven drivers so if you sat at the right ear height, phase differences were less than 25 degrees.

Because time alignment is so important, vertical listening position was crucial.  Slowly lower yourself and suddenly a huge image came into focus.  A few inches more and it was gone.  That was in a very large demonstration room where wall reflections mattered less than usual.  I've mentioned before that the reference used when designing these speakers was the Quad ESL-63.

Yep, the wavelengths tweeters should handle make it unwise to use more than one (why does Infinity spring to mind here?).  Tweeters can be made coincident (concentric) with mid-range drivers, as was done by Tannoy and is now brilliantly executed by KEF.  I have not heard the Tannoy re-incarnation by Fyne.

I made reference to the HD-3P Tweeter when being in discussion about the ESL 57, and my intention to attempt to tidy up one of it's obvious shortcomings with the Tweeter. Under the guise of "Hearing is Believing", I made more known about my experiences with Speakers using this Tweeter. 

Referencing the Driver was not a prompt to encourage the use of it, even though that is a consideration I do recommend.

To see that the Tweeters Data is now sought out and added as a further information was not expected to be seen within this Thread. Maybe in a Thread dedicated to the Tweeter as can be discovered on other forums. 

To the on-looker who has an interest in Self Produced Speakers, the added info might be enough to convince the Tweeter is worth a further investigation and worthy of such  contemplation. 

@mijostyn "What is a pseudo line source?"

A true line source speaker does not exist, any more than a true point source speaker can actually exist.  If they could, the energy they emit would have to be crammed into an infinitely small volume, a singularity.  Singularities are hated in physics theory.  If you can get an ounce or two of matter and cram it into a very small volume, you pretty much have the preconditions for the creation of another big-bang and a new universe.

Ribbon speakers probably come closest to a line source, but big electrostatic panels have to use geometry and / or smarts to give the illusion they behave like a point, or a line, somewhere outside the plane of the panel.

Countries with small populations like Australia, New Zealand, Norway, Denmark, Slovenia can all make really good equipment.  Australia even invented WiFi.  But there is little government support or venture capital for start-ups.  The volumes are low, so prices have to be high.

The flip side is that there are very few import duties anymore.  The car industry is wide open to imports.  Ford, General Motors, Chrysler, Toyota have all stopped local manufacture quite recently.  Chinese cars will dominate very soon!

In general I can import stuff and save about 25% compared with buying the same item locally, after allowing for transport costs.

@richardbrand Not only do I have a REAL line source speaker, I have a real line source subwoofer array. Perhaps what you are talking about is the fact that most "line sources" lose their line source behavior at some low frequency depending on the height of the speaker. My system acts as a line source over more than the entire audio band from ZERO hertz to 20 kHz. There is absolutely nothing pseudo about it. Again, you need to read more about line source behavior. It is why my subwoofers are 4 feet apart and by the way there was nothing all that special about Duntech speakers. I installed a pair in a very rich person's home on Miami Beach in the late 70's when real Duntechs were still being made. They were OK for dynamic speakers. They fit the clients decor nicely. Their image was mediocre. The real company folded in the 90s I believe. 

@richardbrand A line source does not have to be thin like a ribbon. The most impressive characteristic of a liner source aside from higher acoustic power is that they do not send any sound up toward the ceiling or down towards the floor. You can make a line source tweeter only 9 inches tall. The problem is the vertical beaming is so bad you can only hear it if your ears are exactly at the same level. Now take an 8 foot ESL dipole speaker system and put it in a room with an 8 foot ceiling and you get a REAL line source that will maintain line source behavior over the entire audio band and have minimal interaction with the room. They only throw sound at the front and rear walls. My listening area has no rear wall, so I only have to deal with the front wall. When dealt with correctly the image produced is better than anything you have ever heard. Honest,