MP3Gain analyzes and losslessly adjusts mp3 files to a specified target volume.
It does not simply do peak amplitude normalization. Instead, it performs statistical analysis to determine how loud the file actually sounds to the human ear.
Multi-MPD (Music Player Daemon) is a web-based client for controlling multiple instances of MPD with multiple outputs each, managing output routing, playlists, and browsing and loading net radio streams (eg Shoutcast, Sky.FM/Digitally Imported).