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Posts Tagged ‘Tjörn’

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It really doesn’t matter where you turn on the microphone or other sensors, there seems to be life everywhere.
There was no exception to this in the nature reserve in Flói, southwest Iceland 17th July 2022. All night I had been recording the bird life in the same place as I have done every year for over a decade. I had gathered all the equipment about noon and was ready to go, when I decided to prepare a coffee before heading to the next recording location.
So it was the perfect time to dip the Hydrophones in the next pond while waiting for the coffee.
The pond was full of life, although it could not be seen or heard on the surface. The soundscape was so interesting it turned out I was recording there for almost three hours.
After a short investigation I saw Agabus and Spined Stickleback. I am sure there were also moth larvae of different species, even some kinds of shrimp, where the sea is not far away. Some of these sounds may also be methane gas being released from the bottom of the pond.
The soundscape in the pond was similar to birdlife. The chorus from the biosphere in the pond came in waves. Sometimes the sounds were few and quiet, but then there came a time when the whole biosphere in the pond needed to be heard.
Below you can hear one such period.
The recording was recorded in 24bit/48Khz, but a lot of these sounds seem to be able to go well above 24Khz. It tells me that the next time I record in this pond, I should do it at a higher resolution, 96Khz or even higher.
It is always quite difficult to record with hydrophones. The sensitivity is such that, once they are in water, the cables must not touch anything that might move, not even the wind. Although the Hydrophones were well immersed in the pond, you can hear many things in the recording, e.g. in planes, car traffic, footsteps and a Black Headed Gull that probably made a sound as it flew over the pond.
This recording didn’t require a lot of editing. However, 20Hz was taken down by -20dB. I thought it was necessary since these Hydrophones have flat frequency range down to 0.4Hz and the MixPre6 down to 10Hz. Most of the rumble that was heard in the original recording was therefore vibrations from cars and air traffic and possibly also from the waves along the south coast. The recording got a very gentle noise reduction and normalized about +7dB, up to -8dB peak level.
Quality open headphones are recommended while listening at low to mid volume.
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  (mp3 256Kbps / 49,6Mb)

Recorder: Sound devices MixPre6
Hydrophones:. Benthowave BII-7121
Pix: Canon EOS-R

Location: 63.900400, -21.192364
Weather: Gust 1-4m, partly cloudy

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Reykjavíkurtjörn

Í vetur bárust landsmönnum þær döpru fréttir að fuglalífi við Reykjavíkurtjörn hefði hrakað mikið síðustu ár. Það leiddi huga minn að því að ég ætti sama sem engin hljóðrit af fuglalífi við Tjörnina. En einhvers staðar á ég þó upptöku sem ég tók upp framan við Iðnó fyrir 30 árum.
Yfirþyrmandi umferðarniður hefur annars valdið því að ég hef ekki lagt það í vana minn að eltast við náttúruhljóð í miðbæ Reykjavíkur.
Framvegis skal verða breyting á, því spennandi verður að sjá hvort mönnum takist að endurheimta þá fugla sem verptu og komu upp ungum við Tjörnina um miðja síðustu öld .
Tvær helgar í janúar gerði ágæis veður. Arkaði ég með upptökutækin niður að Reykjavíkurtjörn sem var ísilögð. Stóð allt eins til að hljóðrita brak og bresti í ísnum, en ég komst fljótt að því að hann var ekki nógu kaldur, of mikill snjór á honum og að vanda of mikill umferðahávaði.
Fuglalífið varð því aðal viðfangsefnið þessar tvær helgar. Ákvað ég að staðsetja tækin á göngubrúnni frá Iðnó að Ráðhúsinu. Tveimur vatnahljóðnemum var stungið í Tjörnina u.þ.b. 20sm fyrir ofan botn með tveggja metra millibili. Fyrir ofan, á brúnni, voru hljóðnemar í XY uppsetningu.
Þarna má heyra hundgá, í fólki gefa öndum brauð og í útlendum ferðamönnum.
Undir yfirborði tjarnarinnar heyrast mikil skvamphljóð frá fuglum sem börðust um brauðið á yfirborðinu, einnig í skúfönd sem oftsinnis kafaði nærri hljóðnemunum. Þá heyrist málmhljóð þegar gengið er á brúnni og eitthvað slæst í burðarvirki hennar.

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In two worlds

In Reykjavik center is a quiet big pond or a lake with many bird species, like Swans, Gooses and Ducks. Often people feed this birds with bread so outburst is normal when birds grasp the breadcrumbs.
This recordings was made simultaneously both above and under water on four tracks. Two hydrophones where placed 2 meters apart and 20 cm above the pond bottom. On the steel bridge above was two cardioid in XY setup.

Above the pond.
Download mp3 file (192kbps / 10,1Mb)

In both worlds. Above and in the pond.
Download mp3 file (192kbps / 10,1Mb)

In the pond.
Download mp3 file (192kbps / 10,1Mb)

Recorder: Sound devices 744 w/552 preamp
Mics: Aquarian H2a-XLR (spaced omni) and Rode NT1a (XY)
Pix: Canon 30D

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