Since I am new here, hello all!

35 years ago, I traded a pair of Warfdale bookshelf speakers for a pair of floor-standing speakers with a friend of a friend because they were too big to fit in his apartment, and since I had a 1900 sq ft loft, I had a lot of room.

The cabinets seemed like they were made in someone's basement tool shop. I had no idea what was inside, but I could see that the drivers were 15 inches, and I needed something big for my listening area. I opened the backs and found an Altec 604C in one, and an Altec 603B in the other.

My guess is that the 603 preceded the 604 and that this guy's dad used the 603B until stereo came along, then bought a 604C and never bothered to upgrade the other. I used them this way myself for 3 or 4 years. They worked OK together except that the 604C was slightly brighter, which I could compensate for with my Dyna PAS that had separate bass/treble controls for each speaker.

I still have the 603B. It has no crossover. It is for sale.