Designed & engineered in JBLs world-famous acoustic engineering facility in Northridge California the 4309 Studio Monitor is a showcase of patented JBL acoustics technologies. This bookshelf loudspeaker features a 2-way design with patented High-Definition Imaging (HDI™) horn technology the patented 2410H-2 1-inch (25mm) compression driver & a 6.5-inch (165mm) cast-frame Pure-pulp cone woofer for powerful dynamics & incredibly accurate sound reproduction. JBLs revolutionary High-Definition Imaging horn geometry is the result of intense research into the nuances of horn design. In search of exceptional high-frequency detail & uniform directivity for smooth in-room response JBL engineers pioneered a design that delivers neutral frequency response both on- & off-axis & provides a seamless transition between the high & low frequency drivers. The JBL 2410H-2 compression driver benefits from the advanced research & applications derived from JBL Professionals "D2" range of transducers. At the core of the 2410H-2 device is a lightweight polymer annular diaphragm that improve high-frequency extension by reducing diaphragm mass. The V-shaped geometry of the annular diaphragm reduces breakup modes eliminating time smear & reducing distortion. The result is incredible dynamics with accurate reproduction & a lack of power compression.