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. Author manuscript; available in PMC: 2015 May 14.
Published in final edited form as: Bioacoustics. 2015;24(1):13–29. doi: 10.1080/09524622.2014.906321

Figure 2.

Figure 2

Rumbles in the presence of different noise sources, at different distances to the microphone, and with different durations. (a) A series of short rumbles (1 to 1.5s duration) and a concurrent engine sound with a fundamental frequency around 30Hz and a second harmonic at 60Hz. (b) A rumble of approx. 2.5s which is heavily masked by broadband noise. (c) Short rumbles with low signal-to-noise ratio, especially in the channel between 50Hz and 100Hz. (d) Far distant rumbles where most of the harmonics are missing.