An audio output device and associated output method produce sound effects that are more natural to a listener are given to a piece of music. A mode is selected from a plurality of modes, and first sound source data and second sound source data are respectively outputted as the sound effects with music data at an output level that is determined based on the mode selected by a mode selection unit.

Techniques are disclosed relating to determining composition rules, based on existing music content, to automatically generate new music content. In some embodiments, a computer system accesses a set of music content and generates a set of composition rules based on analyzing combinations of multiple loops in the set of music content. In some embodiments, the system generates new music content by selecting loops from a set of loops and combining selected ones of the loops such that multiple ones of the loops overlap in time. In some embodiments, the selecting and combining loops is performed based on the set of composition rules and attributes of loops in the set of loops.