The NWZ-S540 series integrates the Digital Linear Phase Speaker System (that enhances sound quality from stereo speakers) in a compact frame. It comes with a larger 2.4-inch LCD screen, and allows users to share music.
It is touted to have an extended battery life of up to 42 hours of music playback, and 6.5 hours of video playback. The NWZ-E440 is said to provide up to 30 hours of music playback and 6 hours of video playback. The E440 also has a 2.4-inch high resolution QVGA LCD screen.
The Walkman S540 features an alarm and a timer. It has voice and FM recording and supports multiple music and video formats. A Content Transfer software transfers files from Windows Explorer, iTunes and Cybershot cameras with a simple drag-and-drop interface.