Sound Control - App-specific volume control
Spotify - Map shows when two people play same song at same time
EarTrumpet - Volume Control for Windows
Deezer - Deezer is a music streaming app created in France. It is available in 180 counties and gets 16 million users a month. 6 million of the users have paid subscriptions. Read more about Deezer.
Volume2 - Volume2 is an advanced Windows audio mixer, a complete replacement for the standard Volume Control.
Last.fm - The world's largest online music service. Listen online, find out more about your favourite artists, and get music recommendations, only at Last.fm