Serial nos 55S725 and 55S726 are Klipsch Heresy 1 series... Made in 1978 , with Alnico V magnets for the K77 tweeter and the K-55V midrange driver , + a Ferrite square magnet for the K-22 12 inches woofer .
-the mids K-700 horn and the tweeter horn are metal /aluminium , these speakers share the HF drivers with the larger Cornwall and the high end Belle-LaScala -Khorn series .
-the crossover is the E network , the cabinets are birch/fur plywood with Klipsch copper badges and cloth grilles ,