Adam S5VA Operation Manual

Contents

Adam S5VA Operation Manual Manual pdf 8 page image

8A.R.T. Accelerated Ribbon TechnologySo far, all loudspeaker drive units, whether they are voice coil driven, electrostatics,piezos or magnetostatics, act like a piston, moving air in a 1:1 ratio. As the specificweight of air is much lower than that of the driving mechanics, there is a bad matchbetween source and load. This is one of the main reasons for the small 1-2% efficiencyof conventional speakers.All ADAM speaker systems take a completely new approach in kinematics to move airand overcome this problem.Based on the original works of Dr. Oskar Heil, who invented his “Air Motion Transformer”back in 1972, new electrodynamical transducers have been developed. The A.R.T.tweeter’s and midrange membrane consist of a lamella-like folded diaphragm whosesingle folds move according to the alternate current, thus squeezing air in and out (seeFig. 1).The A.R.T. principle achieves a 4:1 velocity transformation between driving diaphragmand driven air, i. e. the air moves in and out four times faster than the folds itself aremoving. This superior “motor” is responsible for the enormous clarity and transientreproduction and thus their increased efficiency.Another factor in dynamics is diaphragm area. For practically all drive units, the conearea you can see is the acoustically active area of the loudspeaker. By folding the A.R.T.diaphragm into the third dimension as seen from the listener’s position, the acousticallyeffective area of the diaphragm is increased by a factor larger than 2.5 (see Fig. 2).Thus, a smaller movement is needed for a given sound pressure level, enabling the unitto reach a higher sound pressure level without dynamic compression.Besides these advantages, the membrane construction in single stripes avoids thetypical break up of stiff domes or cones at higher frequencies and the resultant dynamiclimiting.Since the A.R.T. membrane is directly driven by a current, not by a voice coil, it isextremely light and therefore ideally suited for high frequency reproduction up to35kHz. In comparison to magnetostatics and ribbons, the A.R.T. tweeter offers anabove average efficiency of 93dB/W/m, as well as a perfectly linear impedance of 3.2±0.05 Ohms, an equally perfect phase response of ± 1° within the used bandwidth, areasonable directivity characteristic and a thermal power handling that exceeds that of1” domes by a factor of 2 to 3.Area comparison between theunfolded A.R.T. tweeter diaphragmand a 1” dome tweeterThe A.R.T. Principle: moving the air in a4:1 ratio instead of a 1:1 piston motionFig.1 Fig.2