The LCD-X is a planar magnetic design with an optimized diaphragm trace pattern that extracts the maximum volume from lower-powered amplifiers and portable devices. It's also the most neutral of all the LCD Collection, making it extremely popular with audiophiles, recording engineers and musicians alike, for its clarity and fast, accurate dynamics. The X is sensitive enough to be driven directly by portable players like iPods, iPhones and smartphones, but an external amplifier produces better results.