Astell&Kern Billie Jean In-Ear Hi-Fi Monitor Headphone Highlights Advanced Shell Design Dual Armature Drivers Unique "Bore" Design for Presence and Brightness Silver Tinsel Cable Made in Korea Beautiful Inside, Inside and Outside Billie Jean has long been special for musicians around the world. It is a product created by combining world-renowned Jerry Harvey Audio's IEM (IEM, hereinafter referred to as monitor headphones) technology and the expertise of Astell & Kern, known for its quality products made in Korea. Like the Full Metal Jacket Siren Series beloved by audiophiles around the world, we've created the Billie Jean from an all-metal shell, combining SIREN technology to produce the world's ultimate monitor headset in terms of both sound and design. Billie Jean features the patented Freqphase from Jerry Harvey Audio and the same new sound tube design applied to the Diana. The immaculately beautiful full-metal shell, made using aluminium, not only visually impressive, but also enhances the sound quality, so you can enjoy optimal sound without distortion across the entire audio range. 2 2 The optimized size provided by the driver, combined with the silver tinsel and anaerobic copper cables used in the high-end high-end cables, creates an extraordinary sound that cannot be found in current monitor headphone products. Created in collaboration with Jerry Harvey Audio, inventor of the world's leading custom earphones, and audiophile favorite Astell & Kern around the world, Billie Jean lets you enjoy its beautiful design and gorgeous sound at the same time. TECHNOLOGIES USED AT DIANA SIREN SERIES Jerry Harvey Audio has developed an all-new Balanced Armature Driver to deliver reference quality monitor headphones for mastering and mixing jobs. The high-range drivers are designed to deliver everything with minimal distortion, while the top-of-the-line mid-driver delivers excellent, flat sound from 10Hz to 5kHz. The bass driver is engineered for an even sharper lowpass effect without distortion. Freqphase™ Time | Phase Waveguide Many Multi-Driver monitors suffer from headphone, phase and timing issues. Low, Medium and High drives all have different impulse durations. The higher it is, the faster the impulse time of the BA Driver. The lower it is, the slower the response speed. This results in inappropriate arrival times and Phase shifts.