Post by awkwardbydesign on Apr 1, 2022 14:16:31 GMT
Basically I found some online calculators to get the spring rate and wire size for a 3Hz resonant frequency for 15kg (x 4 for a 60kg speaker), then found a spring manufacturer who would make 8 ( cash in an envelope posted to them to avoid taxes and company mark up; £80 for 4 at the time) and back they came. The height of them had to be stable, and compressed height more than the spring-locked height. My current speakers (Tannoy MG12s) are around 70kg, so close enough. I made friction dampers from neoprene motocrosser fork gaiters, and can adjust the height simply by screwing them up or down and locking them with a nut.
They do sway, as the Seismic feet do, but are stable enough.
EDIT. I tried to insert a 7 second video from Flickr but it didn't work.
The jump at the end is camera movement!
