Sound elevator was a fairly large independent based in the pacific northwest. Puget Sound..Thus Sound Elevator. They were bought out by Dover, who was then bought out by TK. They did support some of the old Entry Plus stuff at one time, but I do not know if they do anymore. Your best bet is to contact TK.

It Don't mean a thing if it aint got that swing.

Cool, Free, Johnny Smith courtesy of NPR..HERE
http://www.npr.org/ramfiles/asc/asc25.smith.asx