Figure 4
From: Drum Sound Detection in Polyphonic Music with Hidden Markov Models
Relative occurrence frequencies of various drum combinations in "ENST drums" [25] data set. Different drums are denoted with BD (bass drum), CY (all cymbals), HH (all hi-hats), SD (snare drum), and TT (all tom-toms). Two drum hits were defined to be simultaneous if their annotated onset times differ less than 10 ms. Only the 16 most frequent combinations are shown.