DOLPHIN PHONE

Your Personal Underwater Ear!

Dolphin Phone system:

• HYDROPHONE: A special underwater 'microphone' that picks up weak sound 'vibrations'. Unlike normal microphones which are designed to work in air, the hydrophone is a special pressure transducer which is highly sensitive to underwater sound 'vibrations'.
  
• HANDHELD CONTROL: Amplifies the weak sounds detected by the hydrophone. Plug in the earphones (included), or your Cassette recorder, VCR, or DAT Digital Recorder to capture your encounters with all forms of sealife.
  
• EARPHONES: A set of high quality 'In-Ear' style earphones is provided. We've chosen a high quality set that lets you hear the full sound experience of the Dolphin Phone.
  

WHERE TO GO:

• HARBORS and MARINAS: Take a trip to your local marina and drop Dolphin Phone into the water. Try to get near the entrance. If you are near a major port, try within 300-400 metres of the ship berths and listen as they maneuver. Each boat or ship has it's own characteristic sound. Often you can hear which ones are having mechanical problems with their engines, prop shafts and propellers. You will also hear a lot of Snapping Shrimp (discussed below)
• BOATS: The best place! If you are looking for Dolphins or Whales, go to the areas they frequent. Shut off the boats' engine and listen. Usually, you can hear their vocalizations on the Dolphin Phone before you actually see them! Don't take your boat too close. They will come to you! Meanwhile enjoy their grunts, whistles and songs.
• WHALE WATCHING TOURS: Great fun! A good operator will be able to find the best locations. If you are shooting a video, plug Dolphin Phone into the camera so you can HEAR and SEE the whales. Plus, you will be able to hear whales as they dive for food - often out of view for long periods but within range of your Dolphin Phone!
• DIVING: While you are getting a little 'surface time' between dives, put the Dolphin Phone hydrophone over the side and listen for the sounds of the sealife around you. It's useful as a signal between divers and dive boat, too!
• From the BEACH: Try a wharf, pier or dock that gets you away from the breaking waves of a beach. In some northern climes, you may hear the grunts of seals living nearby.
• LAKES and RIVERS: Nearly anyplace will do. Listen for boats, or in the winter try listening for the sounds made by Ice as it cracks and groans.

WHAT WILL YOU HEAR?

Some places are very quiet; some a sonically 'alive'. You will have to experiment to find the best places. While listening to whales and dolphins is lots fo fun, there are many other creatures which make sounds underwater. Remember also, that before Dolphin Phone came along, listening to underwater sounds was an expensive and time consuming proposition. You may discover underwater sounds that have never been heard! You may also find links between sounds and various habitats. For example, we wonder why 'snapping shrimp' seem to prefer boat marinas where pollution and toxic bottom paints abound, over cleaner waters just outside the entrance. If you want to explore our last earthly frontier, dolphin phone will open up a whole new dimension.

• Dolphins.Whales:
  You will often hear dolphins when you cannot see them. They are easily identified by their high pitched squeeks. They also emit a 'clicking' sound used to locate fish. Sometimes they are very quiet and even though they are close to your boat you won't hear much. Other times, you can hear them through the boats' hull! Whales are generally identified by lower pitched grunts and moans.

You will probably hear more than you will see with whales. Listen to whales as they dive and search for food. Different whale specied tend to emit different noises and scientists are trying to determine the exact meaning of the different sounds. This is an area where 'amateur scientists' using a Dolphin Phone can contribute greatly to the general knowledge about the meaning of these 'vocalizations'.

• Boat Sounds:
  Listen for the crackling and popping of 'Snapping Shrimp'. They seem to thrive in most marinas and in many bays and anchorages. They create a snapping noise with their large claw. Scientists disagree as to the purpose of the snapping. Some say it's a warning to other shrimp nearby. Others say the shrimp shoot out a jet of water from their claw to stun prey. Whatever the reason the snapping goes on day and night. You will also hear a lot of boats. Listen for the different sounds made by sailboats, power boats, Jet Skis, and different outboard motors on dinghys. With practice you can pick out whether a boat uses a diesel or petrol power engine, hear pumps, and bubbles from outboard exhausts. Some boats are very quiet and you can only hear them at a range of 30-50 metres. Some are lounder and you can har them out to 1/2 kilometre or more.
• SEALS and Dugongs (Manatees):
  Both make underwater sounds but not much has been recorded or described in scientific literature. A Dugong nursing pups will call them over distances of a few hundred metres. There is much work to be done recording and cataloging these 'vocalizations'.
• FISH SOUNDS:
  Many fish can make sounds. There are 'Croaker Fish' which as the name implies make 'croaking' sounds. There are species of coral dwelling fish that make sounds by gnawing on coral - perhaps to scare preditors or attract mates. Large Groupers make 'grunts' to signal theiir displeasure at your presence. There may be many more if we start looking for them. Again, this is an excellent place for the amateur scientist to make meaningful contributions to marine science.
• SHIPS:
  Large ships generate very low frequency sounds and vibrations which can sometimes be picked up several miles away. Many factors are involved including speed and direction of the boat. If you are near a port, try listening to a ship as it maneuvers into its berth. Getting within 200 - 300 metres should allow you to have a good listen as tug boats grind their engines and the ship thrusts forward and backwards to position itself at the wharf.

When you get out from the shore on a boat, many of the interfering sounds found close to shore disappear and you are able to hear sounds much further away.

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Sound Samples

These are sounds you might hear while using Dolphin Phone. Just click on the title. Each is shown with its sound spectrogram. Spectrograms show sound structure; like fingerprints no two are exactly the same. . Frequency is represented on the vertical scale. Time is shown on the horizontal scale. Intensity is indicated by the color. Black represents a level of -90 db; Red - 0db. The Yellow area above the spectrogram shown the amplitude.

BONUS!
The software to produce spectrograms is included free with each Dolphin Phone package. It's a great tool for investigating underwater sounds - and more interesting than cable TV! Checkout our BONUS SOFTWARE page for further information.

Dolphin Whistles



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Spectrogram Software

Each Dolphin Phone comes with a free software to produce your own SPECTROGRAMS. It allows you to 'see' underwater sounds and analyze their content. It's a great program written by Richard Horne and generously made available to us for inclusion with Dolphin Phone. It produces graphicssimilar to the type of 'waterfall displays' used by SONAR operators on U.S. Navy Nuclear Submarines to detect and indentify underwater sounds.

WHAT'S A SPECTROGRAM?

'Most ordinary sounds are complex combinations of individual frequency components or harmonics with a wide range of frequency and intensity. A spectrogram is simply a plot of the frequency components of such an audio signal as a function of time. In this Spectrogram program, digital audio recordings (.WAV format) are analyzed to produce a plot of frequency versus time, with harmonic intensity represented by a variable color scale. These spectrograms reveal the fascinating hidden frequency structure of audio signals and can be used for identifying or classifying particular sounds.'

Look at the samples in our 'SOUNDS' section - all of which were processed with this software! Frequency resolution is typically 20 hz or less! Placing the crosshair cursor over any point on the spectrogram shows time, frequency, and level data in a special 'data' window. If desired, you can also save your spectrogram sample as a set of data points for analysis by other programs.

REAL TIME DISPLAYS

The software allows you to display underwater sounds in real time, or from previously recorded tapes. You can also record 'digital recordings' of underwater sounds and save them on your computer hard disk. These features provide many possibilities. It is not necessary to carry your computer into the hostile marine environment to see carry on spectrographic analysis. You can record sounds on a simple ausio cassette recorder, DAT, Camcorder or other sound recorder, then play the tape back into the computer for analysis at a later time. See our 'RECORD' page for futher details.You can also watch realtime display indefinitely and start a digital recording when something of interest is heard.

REQUIREMENTS:

• OPERATING SYSTEM: Windows 95/98, or Windows NT 4.0.
• RAM: 16MB or more recommended. Will run in limited fashion with 8 MB RAM.
  
• DISPLAY: 256 colors recommended.
  
• SOUND CARD: Windows compatible sound card, or equivalent, to record and play back sounds. Not necessary to analyze computer files in .WAV format.
  

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RECORDING UNDERWATER SOUNDS

Dolphin Phone makes a great underwater microphone for your video camera, audio cassette recorder, or DAT (Digital Audio Tape) recorder.
Now you can hear whales and dolphins as well as seeing them on your videos!

The physical connections will depend on your equipment. Dolphin Phone uses a standard 1/8 inch ( 3.5 mm ) stereo jack for earphones. Both LEFT and RIGHT channels are the same - providing MONO output for your recorder. Simply use the appropriate connecting cord to your equipment. You may connect to either the MICrophone input or LINE IN jacks on your recording equipment. Volume level is adjustable using the Dolphin Phone volume control.

If desired you can add a dual stereo plug adapter - costing about $ 1 - so you can both listen to the Dolphin Phone and record at the same time. Visit any electronics store for the cables for your equipment.

AUDIO RECORDERS
Let's talk about audio recorders. We will leave video camcorders out of this discussion because you choose those for their video quality, size, and features - not their audio or sound capabilities. Dolphin Phone works great with all video gear.

Audio recorders come in several forms - reel-to-reel, cassette, mini-cassette, DAT (Digital Audio Tape) and DCD (Digital Compact Disk). There are comsumer grade models and there are professional models. Prices range from $29.95 to well over $10,000 depending on quality and features. There is a good article available from the Society of Amateur Scientists called Recording Nature's Sounds - check it out after you have finished this article.

For general purpose recording of underwater sounds, I suggest you start off simply. Go down to your local electronics shop and look at INEXPENSIVE Cassette recorders. Stay with the full sized cassettes - not the mini variety made for dictation. Here's a guide to some of the more critical specifications you will see in a catalog, or at the store:

• External MIC. Input: VERY IMPORTANT! Make sure the recorder has some means of using an external microphone. Most do, but some models meant for voice dictation only have an internal microphone.
• Frequency Response: this determines how 'hi-fi' the recording will be. Ideally it should be 20-20,000 hz which is roughly the frequency range of the human ear. unfortunately many inexpensive recorders cover only 100-10,000 hz. while a purest might turn their noses at this, remember that most of the underwater sounds that you will encounter will be in the range of 100-6000 Hz or so.

You can always upgrade to better, more expensive recorders when you have gained some field experience. Use a good quality audio tape for best results. A recorder with a 'counter' is nice and lets you keep notes of where and when the recording was made.

Plan a dolphin phone outing visiting some of the places mentioned in our WHERE?page. When you return, play back the tape through your computer sound card, making an audio file (.wav format) that you can process and view with the spectrogram program that comes free with dolphin phone.

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RESERVE YOUR DOLPHIN PHONE FOR CHRISTMAS

Dolphin Phone is now shipping. We are clearing our order backlog. If you would like to reserve one for delivery before Christmas, please fill in the form below. We will inform you by email when they are available.

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Arretec
P.O. Box 3098
Bletchley
MILTON KEYNES MK2 2AD
UNITED KINGDOM


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