This one you have shown here is a bit closer to one I built many years ago. But this one I built is larger and has two rheostats/controls on it with its array of wire wound resistors. I had settings/formulas worked out for decibel level adjusts as to where the two controls were ti be set. But all the info is on an old computer. Funny as I seen this thread as I have been thinking about digging that attenuator box out and using it in conjunction with these Eminence FDM speakers I now have . . . .