BackPlay a program that plays music files from a folder in the background. At login, it scans a directory called "BackPlay" under the user's Music directory, and begins playing any music files it finds there in random order. BackPlay is independent from iTunes. It can be paused from an icon in the status area.
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.
Guayadeque is a music player that aims to be easy to use and fast even for huge music collections. It allows you to automatically or manually download covers, easily organize the music library, edit the ratings of the tracks, add labels to the artists, albums, and tracks, listen to shoutcast radios, download lyrics, show artist information based on last.fm content, and more. It includes a simple, built-in tag editor with picture support.
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.
Mixxx is software for DJs that provides everything needed to create live mixes. It allows you to beatmatch songs and crossfade them together, like you would with turntables and a mixer. It runs without any extra hardware, and offers a wide range of advanced features including comprehensive MIDI controller and vinyl control support. To obtain the lowest latency and highest responsiveness, it uses hardware video acceleration and takes advantage of multi-core CPUs.
Nextls is a console application that keeps track of your music collection using a MySQL database to store information such as length, bitrate, metadata, and where on the hard drive it is located. When Nextls is launched, it will figure out any changes done since the previous run and update the database accordingly. The database is very simple to work with, and there also exists a sister project in Nx2 that will allow you to take your database online and stream your music from a Web browser.