Method for fast (real-time) storage and retrieval of digital code sequences, each representing one or more predetermined features of a musical note, a fraction of a musical note, or group of musical notes and a system that implements this method, with the aim to automatically control electronical musical devices and thereby to avoid or alleviate certain problems associated with the prior art. The described embodiments of the invention will increase rapidity and efficiency even more by pre-selecting on the basis of related data or by using statistical information.