These are sounds you might hear while using Dolphin Phone. Just click on the title. Each is shown with its sound spectrogram. Frequency is represented on the vertical scale. Time is shown on the horizontal scale.
Intensity is indicated by the color.
Red - 0db. The Yellow area above the spectrogram shown the amplitude. The software to produce spectrograms is included free with each Dolphin Phone package. The skipper is rev'ing the engine while warming it up. As the engine rev's you can see a very clear 'whine' centered around 640 hz.