The LS5/9 was designed by the BBC Research Department and manufacture under licence by Rogers. Production started circa 1983, and continued well into the '90s.
It was intended to be used in locations where the much larger LS5/8 would be inappropriate. The BBC Design Report (BBC RD 1983/10) makes interesting reading and is well worth downloading.
Drive units
As one of the aims was to produce a close sound quality match with the LS5/8, they chose the same Audax HD13D34H tweeter - a 34mm fabric dome. The BBC fitted a metal grille for protection, which was apparently intended to support the weight of the complete loudspeaker! The assembly was designated LS2/12.
Maplin used to stock the tweeter (MY22Y) but they stopped stocking Audax drive units back in 2004 - it sold for around £25, although it fell to £12.99 before discontinuation. Today, it is possible to find the tweeter as Audax still manufacture it, but be aware that the newer versions measure slightly differently, especially at the HF end.
[Blockierte Grafik: https://www.markhennessy.co.uk/rogers/ls59_woofer.jpg]The bass unit was the matter of some in-house research, and the Design Report details the experimental work to determine the best cone profile and material. A full range of development techniques appear to have been used, ranging from laser interferometry to subjective listening tests. The resulting design, designated LS2/14, was manufactured by Rogers.
No-doubt Rogers benefited from their close relationship with the BBC. Certainly, the bass driver in the LS7 appears to be very similar, sharing the die-cast chassis and distinctive transparent polypropylene cone.
Observant readers might notice that the woofer appears to be wired out of phase. It isn't - I've rotated the drive unit through 180 degrees to cure a rubbing voicecoil, caused by the cone settling on the suspension over time. The wires from the crossover PCB are different lengths, so rather than replacing them, I simply swapped them at the PCB end, thus maintaining correct phase.
Enclosure
[Blockierte Grafik: https://www.markhennessy.co.uk/rogers/ls59_inside.jpg]The enclosure is made using classic thinwall practice - high-quality 9mm birch plywood, critically damped with self-adhesive bitumen pads. This method has largely passed out of favour because of the extra design work and significantly increased manufacturing costs, but it's good to see that a handful of companies are still maintaining the tradition (Graham Audio and Stirling Broadcastare the obvious ones that spring to mind). All internal walls apart from the baffle are lined with Rockwool-type insulation, held in place by black cloth which is stapled to the internal batons that join the panels. Some examples are fitted with thin transparent plastic instead of cloth.
In traditional BBC fashion, the grille is held on with Velcro, and is very difficult to remove once it has been on for a few years. Access to the inside is via the removable baffle which is secured with machine bolts which connect with metal inserts in the batons.
There are similar inserts in the side panels for attaching the speakers to stands. These are plugged with brown plastic caps for aesthetic reasons, and sealed internally by the bitumen damping panels. Additionally there are similar holes in the rear panel which are intended to hold an optional BBC amplifier. This is a conventional mono amplifier, designated AM8/17, and was manufactured by H&H.
None of these fixing holes are visible in the brochure pictures, suggesting that domestic models didn't have them. Also the external tweeter level adjustment tags are also not visible in the later brochure picture - again, I wonder if this was only a professional option?
Crossover
The crossover is mounted on the baffle behind the tweeter, just as it is on the LS3/5A. It is equally complicated!