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Gray whale vocalization

To ensure maximum quality, DE600 compensates for some transmission losses normally encountered in telephony. Here are some examples of what you can hear with the it. The DE600 can open new possibilities in your work.  Click the ‘play’ button to listen.

DE600 Sound Samples

Amplitude plot of a Humpback whale song. Produced by the Spectrogram software that comes with every DolphinEar hydrophone

Humpback Whale Song

Humpback whales are well known for their long complex songs that can last for 30 minutes or longer. Only male humpbacks sing - leading researchers to conclude that they sing to attract females. Interestingly, all of the males in an area sing the same song - repeated over and over - changing but little over the course of the year. Whales in other areas sing songs with different melodies.  Lower audio frequencies are attenuated less in seawater than higher frequencies - thus giving them greater range.  Their vocalizations are easily monitored by the DE600 wireless hydrophone.

Locating a DE600 in the breeding areas produces spectacular listening even if you are 12,000 miles away!

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Mediterranean Marina

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Gray whales aren't well known for their vocalizations which sound more like 'grunts' than songs. Still they are easy to locate and their voices carry quite a distance owing to their low pitch. When examined, the gray whale vocalization looks like a short series of tone bursts. The frequency range of these vocalizations is typically under 1500 Hz.  

Plot of amplitude vs frequency of a gray whale vocalisation over a DE600 wireless hydrophone with cleephone link. Amplutude vs Time of the same grey whale recording de600-samples-gray.wav

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Dolphin Whistles

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Amplutude vs Time of the same grey whale recording Amplitude of those same dolphin whistles

Each dolphin has its own unique 'signature whistle' that identifies it from others. Listening to these whistles lets you identify individual animals.  For the most part, these whistles are primarily low frequency sounds (below 3500 Hz). The chart above shows the amplitude of dolphin signature whistles. In this example, there is a rapid drop off of sound energy below 3500 Hz. Even when whistle components extend above this range, they contain significant low frequency components that are clearly identifiable with the DE600 wireless hydrophone making wide ranging dolphin population studies possible.

Dolphin Echo Location Clicks

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Dolphin echolocation clicks over a DE600 hydrophone and mobile cellphone system. Amplitude plot of the echolocation clicks

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. Frequency analysis of the click train shows them very audible in a 3500 Hz bandwidth. It also shows that the effective bandwidth is only about 3500 Hz.  But, this still provides enough bandwidth the hear and measure the echolocation pulse trains.

FISH SOUNDS

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Fish make sounds with their swim bladders.  Why they do so is another matter. But, thanks to work by a number of scientists and biologists we do know that many species make a considerable amount of noise during the spawning season. Spawning grounds can be identified by conducting sound surveys and kept off limits to anglers and boaters to ensure that fish stocks remain high. The DE600 can be used to keep track of these areas.  Sound frequencies are typically under 1000 Hz.  The 'door knocking' sound made by this fish is shown above as a series of low frequency pulses. Fish sounds are very low in frequency. The frequency plot above shows that most of the sound energy is below 1000 Hz.

Fish sounds are generally under 1000Hz as can be seen in this frequency plot. Most fish with swim bladders make sounds. Each species has a characteristic sound allowing a hydrophone, or several hydrophones, to conduct habitat and population surveys remotely by telehone!

This originated using the DE600 tethered in a marina in the Mediterranean. A long distance telephone call was placed from the United Kingdom where the sounds were recorded. You are hearing snapping shrimp with a few wavelets slapping against the sides of boats. You can hear the sharp high frequency clicks come through with excellent quality.

This is a 60 second clip recorded from a phone in the UK that called the DE600 at the Vatnajokul Glacier in Iceland. The clicks and pops you will hear are from the release of ancient air trapped within the ice for tens of thousands of years. When the glacial ice melts it releases this trapped air making the sounds you hear. By listening to the rate and  spectral frequency we can estimate the melt rate of the glacier.

Glacier melt sounds in Iceland

Melting Glaciers (Iceland)

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Underwater sounds from a marina berth in the Mediterranean sea.