Onset refers to the beginning of a musical note or other sound. It is related to (but different from) the concept of a transient: all musical notes have an onset, but do not necessarily include an initial transient.
- Increases in spectral energy
- Changes in spectral energy distribution (spectral flux) or phase
- Changes in detected pitch - e.g. using a polyphonic pitch detection algorithm
- Spectral patterns recognisable by machine learning techniques such as neural networks.
The aim is often to judge onsets similarly to how a human would: so psychoacoustically-motivated strategies may be employed. Sometimes the onset detector can be restricted to a particular domain (depending on intended application), for example being targeted at detecting percussive onsets. With a narrower focus, it can be more straightforward to obtain reliable detection.
- Bello, J.P., Daudet, L., Abdallah, S., Duxbury, C., Davies, M., Sandler, M.B. (2005) "A Tutorial on Onset Detection in Music Signals", IEEE Transactions on Speech and Audio Processing 13(5), pp 1035–1047
- Bello, J.P, Duxbury, C., Davies, M., Sandler, M. (2004). "On the use of phase and energy for musical onset detection in the complex domain". IEEE Signal Processing Letters
- Collins, N. (2005) "A Comparison of Sound Onset Detection Algorithms with Emphasis on Psychoacoustically Motivated Detection Functions". Proceedings of AES118 Convention