Test Bench: BMS 4507ND Dual Diaphragm Coaxial Planar Wave Driver
The BMS 4507ND is a unique transducer that uses a neodymium coaxial compression driver to drive a planar waveguide intended for use in line arrays. BMS Speakers patented the two-way compression driver technology in 1997. This month’s Test Bench subject, the 6.5” 4507ND features a 300-Hz to 22-kHz bandwidth (6 to 22 kHz for the tweeter and 400 Hz to 6.3 kHz for the midrange). The rectangular planar waveguide is optimized for 0° to 15° vertical dispersion and up to 120° in the horizontal plane. This article was originally published in Voice Coil, May 2014.