The Diamond material is extremely stiff, making it the natural first choice in tweeter dome materials. It works as a perfect piston all the way beyond 40 kHz. The very high break-up frequency of the dome keeps the distortion far away from the audible range for unprecedented sound. The White Diamond was launched in 2013. It has undergone steady development over the years while also receiving high appraisal in the market and found a steady sale to ultra-high-end customers around the world. In the earlier years the quantities were so small, they were essentially all produced by our R&D tweeter engineer, Tore Tambs-Lyche, who is now retired. Increased demand and long delivery times meant we had to look at the production setup. Through 2018 and into the spring of 2019 the diamond tweeter was optimized for better performance in the 1-40 kHz frequency range and with improvements in the production processes as well, for higher linear excursion (FEA optimized suspension, verified by measurements) with lower distortion at low frequencies, smoother response and better batch-to-batch consistency. To facilitate this development, SEAS has invested more than 300 hours of engineering, as well as a new Brüel & Kjær NEXUS conditioning preamplifier, which is linear to above 100 kHz, and a Benchmark AHB2 analog power amplifier with low distortion and low noise well beyond 100 kHz, such that the entire measurement chain is geared towards high-res and high-frequency audio measurements. Please note, the data sheet shows the frequency response all the way up to 90 kHz, which is the limit of our Digital Acquisition equipment. The Dark Diamond is a new product, which is launched as a milestone marker in the development of this ultra-high-end product.