Hopefully at this stage you are drawing artist impressions on how the finished article will appear. Presumably you want the unit so that the user can enter in and hopefully edit any now song that comes to mind via controls on the unit? You would like it capable of connecting to an external speaker / amp set up? That bit is probably the easiest - if you start by using a 1/4" jack socket and consider the nature of how it will transmit wirelessly as an upgrade. Will the unit have provision to plug in headphones to use as a standalone?