DE500 Sound Samples: (Click link to listen)

Dolphin Echo-Location Clicks

 This sample cuts off sharply at 3500 Hz yet the clicks are still very audible in the sample.  Echo-location clicks vary widely in frequency with lower frequency clicks being used for long range detection of schooling fish - and perhaps for some form of communications.  The higher frequency clicks are used to pick up individual targets (fish) at close range.  Lower frequencies (in the range that can be heard with the DE500 connected to a cellular phone) propagate longer distances in water and are more useful for detecting the presence of dolphins.

 This chart shows the amplitude of the click pulse train. It shows three distinct pulse repetition rates.  At first, the individual pulses are widely separated indicating a long range search.  The second burst shows closer spaced pulses for medium range searching and finally the last train shows closely spaced pulses for nearby targets.

The frequency analysis of the sound shows that the effective bandwidth is only about 3500 Hz.  But, this still provides enough bandwidth the hear and measure the echolocation pulse trains.

More samples - all using transmission band- widths of 3500 Hz or less!

Dolphin Whistles

Humpback whale songs

Gray whale vocalization

Fish sounds

Long Distance Marina Sounds: Recorded Live from UK