Yesterday we proudly presented our new “SB2” subwoofer on the social media. Many people checked the date and weren’t fooled. But the question remained: what on earth is this sub?
Our R&D engineer Floris Schropp found this Intersonic Servodrive SDL-5 subwoofer on a marketplace. It is a unique subwoofer design from the early 80’s by sound (and rocket…) engineer Tom Danley, for use as part of a sound system for large stadium concerts. Inside the huge W-bin horn sits a module with two 15” cones that are driven by a high-speed rotary servo-motor & belt-drive system, in stead of traditional loudspeakers with voice coils & magnets. This lovely-crazy system could cover the full sub band of 34 to 125 Hz, with a sensitivity of 105 dB/W and a max sound pressure of 135 dBSPL (with 1.5% THD) at 1m with a single box. And with virtually no power compression, a big issue in those days.
The unit that Floris found had been part of Michael Jackson’s European ‘Thriller’ tour system in 1983: a truly unique piece of audio history. Floris restored it with great love and care, like only Floris can. In the pictures you can see parts of the inside of the dual 15” module and a portrait of the proud owner. Oh, he asked if we could place it in our little factory museum to free up some space in his garage…
(Click one of the pictures to open a high res photo gallery).
