How do you actually create the world's first hit composed by a fjord?

You can bet we have asked ourselves that a number of times in this process too! The idea occurred from a completely different context, when we saw measurement data of the seabed in the form of graphs and thought; "hmmm... That looks a bit like music!" That in turn led to the question: is it possible to actually hear the Oslo Fjord? Can the visual data be transformed into something auditory? Be translated.

But who on earth do you ask? Why, Bendik Baksaas of course! An extremely talented (and friendly) composer, and from Horten originally too. Filled with energy and curiosity, he simply dived into the info he got from Kongsberg Discovery. The company is a world leader in seabed mapping and what they gave Bendik to work with was measurement data from the seabed between Horten and Moss.

Horten is tech, but also culture, and in this project they merge.

Jørgen Kvernøy Døhlie at Kongsberg Discovery reveals a little of how their technology works, and how they take measurements:

“When we humans see, we make use of light, and who hasn't noticed how far we can see underwater depends on how murky the water is. When Kongsberg Discovery needs to see the seabed, we use sound. With sound, we are able to plumb the world's deepest oceans, and if there's one thing we're good at in Horten, it's using sound in products in space, underwater, and deep inside the heart.

To see underwater, we use sonars and echo sounders. The sound is sent out with the help of a transducer, called a ‘svinger’ in Norwegian, which vibrates at a given frequency. The transducer vibrates by applying a voltage, and this voltage is controlled from a computer. The range of the sound signal is determined by the frequency at which the transducer vibrates. To get to the bottom of the deepest oceans, we transmit at 12 kHz, and in shallower water we transmit at around 400 kHz. Low frequencies reach deep – think about how far bass sounds carry at a concert. Here in Horten, we also make sonars that see through the seabed; then we have use an even lower frequency, just like with a bass. For the sound from water to be used in music, it has to be lowered to be within the audible frequency range (20 - 20 kHz). Then we "pitch" the sound signal down so that the tone becomes deeper.

When we send sound into the sea, we are able to find out how deep it is. At school we all learned that distance is equal to speed times time. Who hasn’t seen lightning and counted the seconds until we hear thunder? In air, sound takes about three seconds to travel one kilometre (344 m/s), and we can calculate how far away the lightning was. Underwater, we use the same principle with sound travelling about 1500 m/s. Here, there’s an additional challenge in that ocean volume can consist of different viscosities that affect how the sound bends. This is the same phenomenon as when observing an object on the seabed from an angle when we’re swimming.

Just like when counting the seconds until we hear thunder, we record the time of the seabed reflecting the sound signal we sent out. The reflected sound signal causes a transducer to vibrate; the vibration is made into a voltage, the voltage is converted from analogue to digital and then the information is processed on a computer. We then know how long the sound has been in the water, and we can also measure how strong the reflected sound signal was in decibels. This allows us to distinguish between hard or soft ocean floors. To find out how deep the water is, we multiply the time by the speed of sound in water and divide it by two (remembering that the sound travels down and back).

The sound signal we emit can be compared with a flashlight illuminating the seabed. The beam we emit illuminates an area where the strongest reflection is in the middle. When we emit one beam, we call it a ‘single beam’. Creating maps with just one beam takes a long time, so it’s fortunate we have multi-beam echo-sounders. It’s like having many flashlights (‘svinger’ elements) that emit beams in a fan with a certain overlap. The reflected sound signal is also received on several transducer elements, allowing us to calculate where the seabed is. The sound we receive also provides information about the content of the ocean volume, which we call the water column.

 

After receiving information about depths and reflectivity, we can draw a picture of the water column in which we can see what is in the water volume and look at the seabed.

 

Among other things, this technology is used to map the seabed, count fish and provide invaluable information with a view to sustainability. And now it can be used to make music too!

The sound signal we emit can be compared to a flashlight illuminating the seabed. The beam we emit illuminates an area where the strongest reflection is in the middle. When we emit a beam, we call it a singlebeam. Creating maps with just one beam would take a long time, and fortunately we have multibeam echosounders. Then we have many flashlights (transducer elements) that emit the beam in a fan with a certain overlap. The reflected sound signal is also received on several transducer elements, and we can then calculate where the seabed is. In the sound we receive, we also get information about the content of the ocean volume, which we call the water column.

 

After receiving information about depths and reflectivity, we can draw a picture of the water column, and we can see what is in the water volume and see the seabed.

 

This technology is used to measure the seabed, count fish (get into other things ocean measurement is used for, why it is useful for the world and sustainability) and now to make music.