BURMESTER BA31

The BA31 is a two-and-half way speaker that features two Air Motion Transformer tweeters – one is front-firing, the other is rear-firing. The combination of the two should ensure the ideal listening ambiance through system of wall reflections. The AMT principle was developed by legendary Oskar Heil. The AMT moves air in an augmented, semi-perpendicular motion using a folded sheet structured around a series of struts positioned in a high-intensity magnetic field, not unlike accordeon movement. The AMTs have great efficiency so the speakers with them usually exhibit serious HF lift, but they are also very fast and low-distorting. How much of each the AMT in the BA31 should be heard can be adjusted by a knob. The midrange/bass drivers have 170mm impregnated paper cones. The cross-over is set differently for each driver, one at 3kHz, the other at 400Hz. The rear-firing bassreflex port is quite high above floor. Despite that there is much less of polished aluminum that I would expect from Burmester, there is still some - the front baffle, the rear AMT baffle and the base of the speaker is aluminum. The latter also features bi-wirable binding posts.