Spectrogram 4.2 Data D:\Renzo\OilDrum\OilDrum1.wav Event Time Freq Level (dB) a 35 173 -22 b 35 230 -37 (228.5) c 85 348 -36 (349) d 45 429 -34 (429.5) e 141 814 -45 (812.5)