qTunes is a modular music player designed to be simple to install, configure, and use, with a small footprint for low-power systems. qTunes features an AJAX Web interface using Extjs, which can easily handle over 40000 tracks with searching and sorting. It supports multiple zones, allowing you to play different songs in different areas simultaneously. It can stream to Apple Airport devices, including synchronizing over multiple Airports. It uses the DAAP protocol to share music with iTunes. It uses the DACP protocol to allow the player to be remotely controlled by the Apple Remote.app available on iPhone and iPad. qTunes currently plays MP3 and MP4 only, but its modular design allows easy plugin of support for AAC and other formats.
DR14 T.meter is a commandline tool for computing the Dynamic Range of your music according to the procedure used in the offline meter released by the Pleasurize Music Foundation. It is very useful to measure how loud your music is and to understand that a good quality album always has a good dynamic. It's also useful for understanding the effects of the so-called loudness war.
Jaksta Music Miner for Mac automatically captures and tags MP3s from popular audio and video Web sites. Just open Jaksta Music Miner, play a song or video, and the MP3 is created, usually up to 10x faster than real time. The MP3 can be added to iTunes with the click of one button. It supports Grooveshark, Last.FM, YouTube, Jango, and more and is great for discovering new music or enjoying your music offline.