Dual Concentricâ„¢ high frequency 25mm (1") Titanium dome with Tulip WaveGuide Dual Concentricâ„¢ low frequency 150mm (6") treated paper pulp cone with rubber surround. 44mm (1.75") edge-wound voice coil Bass Driver 150mm (6") treated paper pulp cone with rubber surround. 44mm (1.75") edge-wound voice coil