We tested BTS on 44 popular songs performed by 31 artists in the rock and pop music genres. Their tempi ranged from 67 M.M. to 185 M.M. and were almost constant. In our experiment with eight pre-registered drum patterns, BTS correctly tracked beats in 42 out of 44 songs in real time. After the BD and SD had sounded stably for a few measures, the beat type was obtained correctly.
We discuss the reason why BTS made mistakes in two of the songs. In one song, BTS made a half-tempo error, in other words, the output IBI was double the correct IBI. Since onset times on strong beats were often not detected, agents that had the double IBI inhibited agents that had the correct one. In the other song, the beat type was wrong for most of the song. Because SD sounded on every quarter note, the detected drum pattern was not well matched with the pre-registered ones.
Masataka Goto