My goodness.
A lot of emotional input.
Here are some facts:
In 1992 a young creative Engineer, Lars Goller, started as R&D Engineer at ScanSpeak after holding positions at DALI and Vifa. From the start it was clear that Goller often saw things in a different way and often challenged the traditional ways of making loudspeakers. In his first year Goller invented and patented the second generation Symmetrical Drive, consisting of 3 copper rings placed in specific positions in the magnet system. In the early to mid-1990s a range of tweeters based on Lian’s D2905/9000 were developed. A top version featuring SD-2 Symmetrical Drive and a large waveguide faceplate was launched in 1995 and became the iconic -9900 Revelator tweeter that at its time was regarded as the best tweeter available. These tweeters continue to be offered in Scan-Speak’s product line. Goller invented the linear spider that is a key element in Scan-Speak’s Low-LossLinear Suspension which became one of the prime features in most of Scan-Speak’s woofers. This technology enables the suspension to have the same tension during the entire cone excursion allowing the woofers to have the same sound characteristics at low volume as at high volume. In 1997, based on another Goller idea, the first Revelator mid-woofer with sliced cone was introduced. Cutting a number of slices of uneven length and angle through the cone paper and then applying glue to the slices eliminated cone breakup modes which meant a huge improvement in sound quality"
Reference:
Danish Loudspeakrs, 100 Years, 1915-2015.
A lovely coffee table book I encourage you to buy one.
Look, the Scan-Speak 15W/8530K (and variants) is a nice little mid-woofer; I used this 20 years ago... you know, when the catalogues still came on paper and I had stay up til very late at night, so I could make an very expensive international phone-call to a land-line (what is that?!) to place an order...
The patents have long expired.