Yamaha NSX-10000
(1987)

Fourth generation, completely revised and upscale version of the NS-1000 bestseller and masterpiece - still Beryllium loaded.

The original Beryllium domes were made with a process not so distant from the one used for the V-FET transistors from Yamaha... and Sony.
Yamaha gradually refined its vacuum-depositing technique throughout the 1980s until the ultimate step was reached : no more vacuum-depositing on copper-plated aluminium molds but pure beryllium drivers !
That however only happened with the NSX-10000 and the 1991 G-F1 self-powered monster, shortly before Yamaha ducked high-end audio activities.

The use of pure material allows long crystals and therefore less intercrystal losses (like in carbon fibers - see below) for better transmission speed and resolution.

The 33cm "uni-directional long-fiber" carbon fiber bass driver follows on those used in the NS-2000 (1982) and NS-1000x (1984) but refines the formula : it is made of four sheets of long-fiber carbon sheets, each of which is a sandwich of four layers shifted by 45° - 32 pieces of carbon for improved rigidity.
The center cap is also made of a carbon (one piece this time).

Also new was the pure beryllium bobbins (!), further improving heat conductivity and power-handling.
The filter also got completely reworked : metallized paper caps, OFC copper coils, OFC wiring and plasma spot-welding to avoid mixing different metals impeding on signal purity.

The enclosure itself dropped the faux rounded corners (NS-1000, 1000M, 2000 and 1000x are all square enclosures) for a 12-laminate one-piece rounded baffle, the construction of which Yamaha knew a lot about since it started making grand pianos in 1902 ! The surface veneer is the (alas not very pretty) open-pore american walnut.

The drivers' frames were designed with CAD and are all 12mm thick, to (try to) minimize resonance and vibrations ; more 10mm bolts on the drivers' front plates for an even tighter fastening.

The phase plugs went upscale, too, in being made from heavy brass instead of aluminium (better rigidity for improved stereo dispersion) and the mid driver's own sub-enclosure was reinforced and altered in shape (probably rounded ? - see above).

The terminals allow thick cables but not bi-wiring nor bi-amping.

At twice the price of a pair of NS-2000s, NSX-10000 doesn't seem to have sold as much as the CDX-10000 or the CX-10000 - there were perhaps too many pairs of 1000s, 2000s and 1000x around :)