A search device and associated methods use music emotions to browse, organize and retrieve music collections. The search device comprises a processor and an interface. The processor uses machine learning techniques to determine music emotion according to music features and organizes music by emotions for browsing and retrieving music collections. The interface connects to the processor and allows a person to retrieve desired music from the processor. Methods associated with the search device comprise a processor initialization method, a method of loading new music into the search device and several methods of retrieving desired music from the search device.