Tag: Acoustics

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A Sense of Proportion by Sravya Darbhamulla

Ciliate tuba
When the spirit is level
Makes mu-music-math

By Sravya Darbhamulla

A haiku on the inner-ear mechanisms that lead to perceptions of music: the physiology of the ear and the acoustic-electric transform; and a reference to inner-ear fluid being balanced.

Further reading:

‘Neuroanatomy, Auditory Pathway’, 2023, Peterson DC, Reddy V, Launico MV, et al., Treasure Island (FL): StatPearls Publishing. Available: https://www.ncbi.nlm.nih.gov/books/NBK532311/

‘Why do humans like jazz? (evolution of music, entropy, and physics of neurons)’, 2023, Physics of Birds YouTube channel. Available: https://youtu.be/Gc5eICzHkFU?si=UTkvJ_j9yMpn1cnx

Author bio:

Sravya Darbhamulla is an archivist, translator and aspiring interdisciplinary researcher with a background in linguistics. She can be found on X/Twitter @acuriousshawl.

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Rigs to Reefs

Oh puffing pig fish –
torn between disturbance and
piscine temptations.

Noise pollution from oil and gas drilling platforms can have huge negative impacts upon marine life. However, such rigs can also act as artificial reefs, providing shelter and a hard substrate for predators and prey alike. Moreover trawling isn’t permitted close to rigs, meaning that the seabeds around them are mostly untouched.

Harbour porpoises, Phocoena phocoena, have previously been shown to change their behaviour or avoid areas as a result of unnatural noise levels. Yet a recent study by Tubbert Clausen et al. (2021) has revealed that the temptations of high prey availability can overcome such affects. The team use 21 acoustic loggers, placed on the seabed for up to 2 years to monitor noise levels and harbour porpoise activity.

They found that despite the high noise levels from the largest rig in the Danish North Sea, the porpoises were still found close to the rig, emitting echolocation noises that indicate they were hunting for fish. The platform’s artificial reef effect appeared to increase fish numbers which drew the porpoises closer.

The findings suggest that as platforms come to the end of their lifespans, they could be partially left in place to continue acting as artificial reefs – the rigs-to-reefs concept.

The first line of the sciku refers to two names for the harbour porpoise:

– The ‘pig fish’ from the Medieval Latin porcopiscus, a compound of porcus (pig) and piscus (fish).

– The ‘puffing pig’ which comes from the noise the porpoises makes when surfacing to breathe.

Original research: https://doi.org/10.1002/2688-8319.12055

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How sad a solo?

Alone. How tragic.

Unless that’s what’s intended?

How sad a solo?

 

Orchestras have a vast array of instruments, yet composers frequently employ a solo instrument within orchestral passages. Hansen & Huron (2018) have investigated whether a solo is used to convey or enhance a sad effect.

By characterising orchestral passages as featuring a solo or not and then investigating the differences between they were able to assess the impact of a solo on the emotion of the piece. Whilst they acknowledge that composers might use a solo for a number of reasons, their results suggest that there is an association between sadness-related acoustic feature and solos. Indeed, pieces of music with sad characteristics are twice as likely to feature solos.

Original research: http://dx.doi.org/10.1525/mp.2018.35.5.540

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Underground sound

Listening for sound

whilst deep underground requires

middle ears to hear.

 

Animals living in different environments will face different auditory challenges. To investigate how environment shapes evolution Koyabu et al (2017) compared middle ear morphology across terrestrial, aquatic and subterranean species from the order eulipotyphla (including hedgehogs, moles and shrews).

They found that a subterranean lifestyle involved adaptations that allow for improved sound transmission at low frequencies and reduced transmission of bone-conducted vibrations. The adaptations observed included “a relatively shorter anterior process of the malleus, an enlarged incus, an enlarged staples footplate and a reduction of the orbicular apophysis”.

Original research: https://doi.org/10.1098/rsos.170608

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Just nicker!

Don’t make yourself hoarse

in anticipation of

good times, just nicker!

 

Vocal communication is an important element of behavioural interactions within many social species.  Przewalski’s horses produced more whinnies and squeals in response to negative contexts (agonistic interaction, social separation), but more nickers in positive contexts (anticipation of food or affiliative interactions).

Przewalski’s horses are the closest living relative of domestic horses and a comparison between the species revealed both similarities and intriguing differences in their vocalisations, suggesting that the expression of emotional valence (positive or negative) might be species specific as opposed to conserved across species. Maigrot et al, 2017.

Being able to understand vocal expression of animals could lead to the increased welfare of captive species and a better understanding of animal interactions and group behaviour, which in turn might help to aid population management or conservation in endangered species.

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Just a warm up

Oh how sweet dawn’s song!

Yet this choral crescendo

is just a warm up.

 

Many of us enjoying waking up to the sound of birdsong. But whilst we might enjoy the various trills and tweets as the sun rises, the Adelaide’s warbler’s song actually improves over the course of the morning. To appreciate the best of its voice, perhaps the early bird doesn’t catch the worm! Schraft et al, 2017.

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Road-safety

Road-safety crucial:

Engine noises distract from

predator odours.

 

Noise pollution can have a number of effects on wild animals. Morris-Drake et al (2016) found that road noises meant that dwarf mongooses were slower to detect a predator odour and did not increase vigilance in response to the odour (whilst mongooses exposed to normal ambient noise found the odour faster and showed increased vigilance).