The Euro-American nation develops in the loudspeaker up has been be placed in a leading position. 10 years ago, Hi-Vi engineers hope to look for a break, which will make Chinese people also can design a new generation loudspeaker with high index and performance by ourselves. At that time our springboard is to design a small caliber loudspeaker, using a small box can produce a very grand low-midrange sound field. Its voice should be neutral and nobler, it also should be a modern art article. Now this D series loudspeaker basically achieve our original conceive, the D series loudspeaker adopted the latest design in a series of world new concept. Shallow mineral filled polypropylene cone; Specially made high loss rubber surround; Shielded vented magnet system with Neodymium magnet; Long-throw symmetrically driving motor structure with linear excursion increased up to 5.3 mm; High power handling voice coil with 76 mm Kapton?former; High density aluminum die-cast frame; D6.8 represents a design where the voice coil is positioned over an undercut central pole piece with large thermally stabilized Neodymium magnet at the bottom. A specially shaped, CNC machined steel cup completes the magnetic structure from the outside, creating a shielded magnet system with symmetrical flux density distribution along the gap. The long-throw voice coil experiences a symmetric driving force and substantial decrease of inductance and back electromotive force modulations. The whole magnet structure is optimized using Finite Element Analysis. The result is a radical improvement of driver linearity. The cone has a shallow, high integrity structure, which is extremely rigid and dynamically stable. The large voice coil diameter allows more uniform cone excitation, thus improving phase and transient characteristics of the driver, resulting in clear and accurate reproduction. The vented design and a high temperature rated voice coil provide a dramatic increase of power handling. D6.8 is suitable for a wide variety of vented box systems. This driver is capable of delivering the deepest possible base for a minimonitor speaker. It also may be incorporated in a small (6-7l) enclosure as a bass-midrange driver, when a subwoofer is employed.