The CS5 was designed 'on demand', most notably for the Japanese market which wanted a 'Hear God' loudspeaker from Thiel. As such, the CS5 displaced a potential CS4 which would have been an incremental advance over the CS3.5. The CS5 was also on a forced time-table because the market was brimming with new 'statement' models from many manufacturers. Contrary to street talk, the CS5 was not a 'price no object' product. It respected and solidified Thiel's approach to working within budgets determined by eschewing superfluous costs and concentrating on high-value, cost-effective solutions. Our internal, working retail target was $15K/pair, but by trimming fat, we brought it to market at $9300/pair. As manufacturing director, I advocated unsuccessfully for a higher price with further enhancements - notably more advanced cabinet construction.
By 1988, Jim had taken the plunge into Finite Element Analysis which he applied to driver design to develop many solutions that subsequently became embedded in the industry at large. His first FEA-enhanced design was the 1988 CS1.2 tweeter with a copper voice-coil shorting ring which shunted voice coil eddy currents to meaningfully increase onset transient integrity. That driver paved the way for the more ambitious CS5 UltraTweeter with underhung motor topology and 1/10th the distortions of previously available drivers (at any price.) The UltraTweeter served the CS5, CS5i, CS3.6, and CS2.2. It was dead-ended by our choice of coaxial tweeter-midranges to solve the inherent vertical interference problem of first order x time-aligned drivers. The CS5 upper midrange was an off-the-shelf MB-Quart 51mm dome. Those two top drivers are the same in the original CS5 and the later improved CS5i version.
The CS5i applied newly developed motor changes to the lower midrange, woofer and two subwoofers. Specifically, we had identified pole-piece eddy currents as a previously invisible, but sonically important distortion mechanism. The first-generation solution was to taper the diameter of the pole piece from its required diameter at the voice coil, gradually diminishing toward the motor back plate to better manage the magnetic fields. These improvements were made possible by developing our in-house driver development lab in the early 1990s. We iterated dozens of proof of concept drivers with 1-day turnaround rather than 1 month turnarounds working with our Danish (Vifa / ScanSpeak) supply partners. We made all elements including cones which we spun with our shop-made mechanical/hydraulic spinner. The hand built prototype driver was driven 40 miles to Eminence Speaker who had made our 01 / 03 woofers and had the first Klippel development system in North America. They authenticated / verified our lab measurement results and projected Thiele / Small parameters.
Bottom line is that we upgraded the motors of the Focal lower midrange, and ScanSpeak woofer and subwoofers with tapered pole-pieces and tapered-edge top plates. Those drivers use the same moving system and crossover circuitry as the original CS5 while substantially improving fidelity. Most CS5 owners upgraded to the CS5i. That upgrade kit included the 4 new, drop-in drivers only.
Rob at CSS has no CS5i drivers, but he does offer moving system replacements which are the same for the CS5 and CS5i. The only visual difference between the 5 and 5i is the mass loading of the subwoofers. The original rubber mats proved troublesome via eventual corner lifting of of the mats. The 5i MDF center plugs perform the same loading function without the hassles. If you find a pair of original 5s, the bottom 4 drivers have state-of-the-art 1988 technology. The CS5i subs, woofer and lower-midrange drivers substantially better that performance in the low end.
