|This is the spectrogram of a boat at a range
of approximately 200 metres (650 feet). The skipper is rev'ing the engine
while warming it up. Listen carefully to the sound sample and you can hear
the pistons operate! As the engine rev's you can see a very clear 'whine'
centered around 640 hz. You can also hear 'snapping shrimp' in the background.
(mostly showing as a light 'blue' color)
Sounds are clearly picked up all the way down
to 1-2 Hz, showing the quality of the DolphnEAR hydrophone! Human hearing
has a lower limit of about 18-20 Hz, so using DolphnEAR with the Spectrogram
Program lets you 'see' sounds you normally cannot hear. This is a useful
feature if you go hunting for long range (up to 100-150 Kilometres) whale
This sample was made using an inexpensive cassette
recorder ($40). DolphnEAR was connected to the MIC INPUT jack.