The SP-12 was the big brother (beefier) of the SP-12B. The SP-12B was a phenomenal speaker for its day (around 1950) and that means it will still sound good. I used mine in a copy of an Electrovoice corner horn cabinet that I built in College. It sounded just great! I later added a Karkson cabinet and the combination of the two stacked was phenomenal. This was before stereo. -Dick