Precision cast and surface treated magnesium cone coupled to a natural rubber surround showing no sign of midrange (edge) resonances. Patented Hexadym magnet system of acoustically transparent design to avoid cavity resonances and air flow noise. The magnet system based on 6 small, radially magnetized Neodymium blocks is compact to reduce the reflexion of sound energy to a minimum. Heavy copper rings mounted above and below the T-shaped pole piece reduce non linear and modulation distortion and increase overload margin. Extremely stiff and stable injection moulded metal basket keeps the critical components in perfect alignment.