Equalizer + Marshall Edition is a specialized music player designed exclusively for the Marshall London Phone, offering a robust platform for music enthusiasts. It features a five-band equalizer that allows users to finely tune their audio experience, complemented by a powerful bass booster for enhanced sound quality. The app provides direct access to the user's music library, enabling seamless navigation through songs, albums, and playlists. With its background play mode, users can enjoy uninterrupted music while multitasking or in standby mode.

The application stands out with its ten pre-set equalizer settings tailored to various music genres, along with options to create and manage custom presets. Additional functionalities include a visible music progress bar for easy song navigation, repeat and shuffle options for playlist management, and a visualizer for an engaging listening experience. The app's ability to record customized presets further enhances its usability, making it a comprehensive tool for music playback and adjustment.