2.1. Background of problem
2.1.1. Sonic nature of drum sounds and break beats
Sounds emanating from most type of percussion instrument are created by the impact of a stick or hand on a resonant surface (eg a drum skin) or the setting in motion of objects that create sound (eg the beads of a shaker or the bells of a tambourine). The spectrum of frequencies produced by these instruments is thus created at the very start of the instrument being hit and is followed by a decay in amplitude of these frequencies at varying rates. It is thus argued in this report that recognition can be performed by the analysis of one static frequency spectrum measurement taken from the start of each drum.
2.1.2. Existing recognition software
Although much sound recognition software exists, for instance speech and speaker recognition, there does not appear to be any software in the public domain aimed at the specific task of recognising drum sounds.
2.1.3. Recognition problems
Recognition problems fall into a number of different categories:-
- The sonic characteristics of different drum kits vary
- The types of sound processing (eg equalisation/ compression/ reverberation) used in recording drum kits varies
- The frequency response of recording media used in different studios in different times varies greatly
- Sound quality can in some case be very poor especially if the break is sample from an old vinyl recording
- The sound of one drum can over spill into the sound of the next, obscuring the clarity of quieter drum hits
- Background noise such as mains hum, or sounds from other musical instruments, can also obscure the clarity of quieter drum hits