Audio speaker assembly mounts for a vehicle, and particularly an open vehicle, such as an off-road vehicle, to provide improved audio sound to the passengers of the vehicle and to prevent theft of the speakers mounted in the normally opened vehicle. The mounts include speaker box kits that are affixed to sport rollbars of the vehicle, and consist of at least one pair of elongated shells fixedly secured together in a watertight configuration to a section of the rollbars, and has at least on locking element therein so as to secure the kits together and to the rollbars as well as secure the speakers and other equipment held within the elongated shells.

There are disclosed an apparatus adapted to generate musical information of a synthetic sound in accordance with the MIDI (Musical Instrument Digital Interface) standard to carry out PCM (Pulse Code Modulation) recording of a natural effect sound including natural sound and/or a human voice such as back chorus to mix them to generate musical accompaniment, thus to mix a voice of singing sung with the musical accompaniment, and a recording medium used for such an apparatus.

An electronic system having a function to output history information of error. A microprocessor assembled in the electronic system stores, into a memory unit, every occurrence of error, error information indicating the contents of errors of various controlled units constituting a mechanical deck unit controlled by the microcomputer, and accepts or receives a command of an operation unit to read out error information indicating those error contents from the memory unit to display history information of error on a display unit.