KLH Model 12 Speaker?

You probably need to rebuild the cross-overs. To confirm the contour/cross-over boxes are not working, wire the speakers directly to your amplifier instead of through the contour box.With a VERY LOW volume setting listen to some music and hear if the drivers are working. If you get sound out of all the drivers then the caps in the cross-overs are shot and need to be replaced. That is what was wrong with mine. They are a nice speaker when working properly.

I have some model 12s with pretty decent enclosures but I think the tweeters and maybe some of the mids are not working. If you're still out there, maybe we should get together. If you're not, I'm open to other suggestions. Otherwise, they're going to goodwill the next time I make a trip.

Long ago I had KLH12s. They were the first speaker system I ever bought, rather than designed and built. The drivers are identical to those used in the KLH5, but the enclosure was floor standing, and heavy, and the crossover was "outboard" in what you call the "contour" controls. This was perhaps the best of the early AR and KLH acoustic suspension speaker systems. Certainly the best ever made by KLH except for the electrostatic KLH9.

The drivers were good in their day, but I am sure that age has taken its toll on the ones you have. I don't think anyone is going to build the enclosure, but perhaps someone still has the speakers and could use spare drivers.