Abstract: The loudspeaker system of the invention comprises at least one enclosure, at least one fastener, a sound amplifier unit, at least one speaker unit, at least one power supply unit, and an audio signal connector. The enclosure comprises a bottom face which is contoured to fit the shoulder strap of a backpack. Each of the fasteners is connected to each of the enclosures. The fasteners are used for fastening the enclosures on the shoulder straps. The sound amplifier unit is electrically connected to the speaker units, the power supply unit and the audio signal connector. The sound amplifier unit is contained in one of the enclosures. Each of the speaker units is contained in each of the enclosures. The at least one power supply unit is contained in the at least one enclosures. The audio signal connector can be electrically connected to an external audio rendering device.