Adam Audio-A77X Starting with the X-ART tweeter, its actual diaphragm area (if unfolded) is four square inches (the equivalent of a 56mm dome tweeter in area) with a velocity ratio of 4:1. Crossover is at 3kHz and the tweeter reaches up to 50 kHz. The A77X’s 7-inch woofers appear to share all the characteristics of the premium SX-Series, a “double sandwich” of fiberglass/carbon fiber/Rohacell and high excursion. One of its woofers handles only 400 cycles and below, while the other reproduces lows as well as mid content up to 3 kHz, where the ribbon takes over -- a “2.5 way” design, perhaps? Each woofer is powered by its own 100W PWM-type amp, whereas the tweeter has its own 50W A/B-type amp. The rear panel houses both XLR and RCA inputs, a low- and high-frequency shelving EQ control (at 300 and 5kHz, respectively, + or -6 dB) and a tweeter level control (+ or -4 dB).