BpmDj is a program that can be used by a DJ. It plays MP3 and Ogg files. It has a fully automatic BPM counter. It can determine the sound color. It has a full fledged Qt based interface. It will help you manage a large amount of songs. It can help in creating playlists and has proven to be very robust. The program also allows offline automatic mixing and contains a wavelet based beat graph analyzer to visualize audio tracks.
GSmartMix provides a smart control of the audio on GNOME. There is also an applet which allows manual adjustment of sound per application. Each application using GStreamer can benefit from this project without any intrusive patch. Other applications should implement the D-Bus interface proposed with GSmartMix to be seen by the smart manager.
Mixer.app is a mixer utility for Linux/FreeBSD systems. It is designed to be docked in Window Maker. This utility has three volume controllers that can be configured to handle any sound source, the default sources are master-, cd- and pcm-volume. Sound sources can easily be muted and there is also wheel mouse support.
OpenAL Soft is a cross-platform implementation of the OpenAL 3D audio API. It's based on the open-sourced Windows version from openal.org. It provides capabilities for playing audio in a virtual 3d environment. Distance attenuation, doppler shift, and directional sound emitters are among the features handled by the API. More advanced effects, including air absorption, low-pass filters, and reverb, are available through the EFX extension. It also facilitates streaming audio, multi-channel buffers, and audio capture.