38 a or the infrared transceiver 38 b for purposes of data transfer to the other device u2014 to the display keyboard processor 35 and to the duplicate unit 1 a over by way of example a universal serial bus 38 a or an infrared transceiver 38 b needless to say this transfer can be very fast up to 10 mbits second accordingly large numbers of tracks of musical works which are stored in mp3 or related compressed format on the hard drive 30 of one unit may be transferred i in gross ii in accordance with a u201c transfer list u201d analogous to a u201c play list u201d iv as differing in title or v track by track under user control to the hard drive 30 of the other unit the transfer mode iv is especially powerful permitting a user operator owner with a virgin hard drive but access to another fully populated cd rom and mp3 recorder player in accordance with the present invention such as might be owned by a friend to load large numbers of musical works typically up to the approximately 1200 that will fit within a 10 gbit disk storage to his her unit in mere minutes additional elements shown in the schematics of fig1 4 will be substantially self explanatory to a practitioner of the electronic music system design arts power is normally supplied through three separate options 1 110 220 volt a c input 2 a battery jack or 3 batteries.