The FD5 introduces a truly high-end driver design - a magnalium diaphragm DLC gasket driver. By innovatively combining these two materials, not only does the FD15 deliver a spacious and relaxed natural sound, but it does so while achieving new heights in the reproduction of musical detail for truly transparent sound. The FD15 boldly embraces high-end audio design principles by introducing the W-shaped gasket design to earphones. Compared to conventional diaphragms of the same size, the FD15 boasts a 30% increase in effective vibrating area. With a larger effective diaphragm area and greater amplitude, the core acoustic unit can store more sound energy, delivering a denser and more solid listening experience. Inspiring new acoustic thinking, with special attention to immersive bass. The FIIO FD15 takes the lead by incorporating the F.T.B.S. ‘Tesla Valve’ bass enhancement acoustic design.