In regard to DIY Speaker Building, the United Kingdom was uniquely sophisticated and ahead of the game up to the late '70s. There were many sophisticated designs, ranging from DIY LS3/5a, the 2-way Tabor, to the 4-way B.J. Webb transmission line tower, The PRO-9-TL, and too many designs to number from KEF themselves, to Falcon Acoustics, to Badger Sound Services, Wilmslow Audio, and others.
The USA had DIY designs from the big speaker companies JBL, Altec-Lansing, Electro Voice, Hartley, and Utah (and Lafayette and Allied with rebadged drivers from them). But the DIY bug started to develop commercial strength in the USA around 1980, and possibly surpassed the general sophistication of British designs.
Now, as we speak, I have lost contact, and cannot discern the market conditions for DIY speakers anywhere. It seems the flame is much smaller now. That's an opinion in regard to this market niche in hifi.
I could not truly say which country carries the torch in hifi now, and could not tell the "nationality" of some strong brands anymore. For example, what is the country of McIntosh, Marantz, Wadia, etc?
NHT is from USA, and so is Polk, Gallo Acoustics,Thiel, VPI, AVA Audio, Sound Smith, Grado, Pass Laboratories,Bob Carver ( http://www.bobcarver.com
), James Bongiorno, http://www.goldenear.com
speakers, and http://www.gttgroup.com
, Wilson Audio Speakers, Audio Research, Magnepan, Vandersteen Speakers, Manley Amplifiers, Boulder Amplifiers, Graham tonearms, Klipsch. and others I forgot.
But I could not even begin to identify British brands apart from KEF, Tannoy, Wharfedale, Rega, Naim, Monitor Audio, B&W, Spendor, Harbeth, Linn, Goldring, Creek, Musical Fidelity, Monitor Audio, Quad?? etc.
Too many absent from this in order to have a true perception. And the only hifi manufacturer we had in Puerto Rico was Euphonics, with their strain gauge Miniconic cartridge which closed shop around 40 years ago. I attempted to start DIY speaker manufacturing from my own garage, and managed to build several pairs for friends who I invited for dinner, who did not pay for using my long defunct woodshop (hardly an "industry"
Good hunting for national superiority, cafe latte,
P.S.- yes, Bob Carver (see above) and James Bongiorno ( http://www.ampzilla2000.com
) are ba-a-a-ck with some killer amplifiers!