The minimum detectable delay of speech and music

The minimum detectable delay (MDD), or the threshold above which a single coherent echo can be perceived, is found to be 20 milliseconds for music and 23 milliseconds for speech. The MDD is plotted as a function of echo intensity level. Total sound pressure level and echo angle of incidence do not affect the MDD. Drum taps are introduced as a convenient test signal. The drum and bugle corps drumming execution judging criterion was used and proven to be a consistently accurate method of finding the MDD.