̽��ֱ�� of Cambridge - sound

Pythagoras was wrong: there are no universal musical harmonies, study finds

ta385 — Tue, 27 Feb 2024 09:30:00 +0000

According to the Ancient Greek philosopher Pythagoras, ‘consonance’ – a pleasant-sounding combination of notes – is produced by special relationships between simple numbers such as 3 and 4. More recently, scholars have tried to find psychological explanations, but these ‘integer ratios’ are still credited with making a chord sound beautiful, and deviation from them is thought to make music ‘dissonant’, unpleasant sounding.

But researchers from the ̽��ֱ�� of Cambridge, Princeton and the Max Planck Institute for Empirical Aesthetics, have now discovered two key ways in which Pythagoras was wrong.

Their study, published in Nature Communications, shows that in normal listening contexts, we do not actually prefer chords to be perfectly in these mathematical ratios.

“We prefer slight amounts of deviation. We like a little imperfection because this gives life to the sounds, and that is attractive to us,” said co-author, Dr Peter Harrison, from Cambridge’s Faculty of Music and Director of its Centre for Music and Science.

̽��ֱ��researchers also found that the role played by these mathematical relationships disappears when you consider certain musical instruments that are less familiar to Western musicians, audiences and scholars. These instruments tend to be bells, gongs, types of xylophones and other kinds of pitched percussion instruments. In particular, they studied the ‘bonang’, an instrument from the Javanese gamelan built from a collection of small gongs.

“When we use instruments like the bonang, Pythagoras's special numbers go out the window and we encounter entirely new patterns of consonance and dissonance,” said Dr Harrison, a Fellow of Churchill College.

“ ̽��ֱ��shape of some percussion instruments means that when you hit them, and they resonate, their frequency components don’t respect those traditional mathematical relationships. That's when we find interesting things happening.”

“Western research has focused so much on familiar orchestral instruments, but other musical cultures use instruments that, because of their shape and physics, are what we would call ‘inharmonic’.

̽��ֱ��researchers created an online laboratory in which over 4,000 people from the US and South Korea participated in 23 behavioural experiments. Participants were played chords and invited to give each a numeric pleasantness rating or to use a slider to adjust particular notes in a chord to make it sound more pleasant. ̽��ֱ��experiments produced over 235,000 human judgments.

̽��ֱ��experiments explored musical chords from different perspectives. Some zoomed in on particular musical intervals and asked participants to judge whether they preferred them perfectly tuned, slightly sharp or slightly flat. ̽��ֱ��researchers were surprised to find a significant preference for slight imperfection, or ‘inharmonicity’. Other experiments explored harmony perception with Western and non-Western musical instruments, including the bonang.

Instinctive appreciation of new kinds of harmony

̽��ֱ��researchers found that the bonang’s consonances mapped neatly onto the particular musical scale used in the Indonesian culture from which it comes. These consonances cannot be replicated on a Western piano, for instance, because they would fall between the cracks of the scale traditionally used.

“Our findings challenge the traditional idea that harmony can only be one way, that chords have to reflect these mathematical relationships. We show that there are many more kinds of harmony out there, and that there are good reasons why other cultures developed them,” Dr Harrison said.

Importantly, the study suggests that its participants – not trained musicians and unfamiliar with Javanese music – were able to appreciate the new consonances of the bonang’s tones instinctively.

“Music creation is all about exploring the creative possibilities of a given set of qualities, for example, finding out what kinds of melodies can you play on a flute, or what kinds of sounds can you make with your mouth,” Harrison said.

“Our findings suggest that if you use different instruments, you can unlock a whole new harmonic language that people intuitively appreciate, they don’t need to study it to appreciate it. A lot of experimental music in the last 100 years of Western classical music has been quite hard for listeners because it involves highly abstract structures that are hard to enjoy. In contrast, psychological findings like ours can help stimulate new music that listeners intuitively enjoy.”

Exciting opportunities for musicians and producers

Dr Harrison hopes that the research will encourage musicians to try out unfamiliar instruments and see if they offer new harmonies and open up new creative possibilities.

“Quite a lot of pop music now tries to marry Western harmony with local melodies from the Middle East, India, and other parts of the world. That can be more or less successful, but one problem is that notes can sound dissonant if you play them with Western instruments.

“Musicians and producers might be able to make that marriage work better if they took account of our findings and considered changing the ‘timbre’, the tone quality, by using specially chosen real or synthesised instruments. Then they really might get the best of both worlds: harmony and local scale systems.”

Harrison and his collaborators are exploring different kinds of instruments and follow-up studies to test a broader range of cultures. In particular, they would like to gain insights from musicians who use ‘inharmonic’ instruments to understand whether they have internalised different concepts of harmony to the Western participants in this study.

Reference

R Marjieh, P M C Harrison, H Lee, F Deligiannaki, and N Jacoby, ‘Timbral effects on consonance disentangle psychoacoustic mechanisms and suggest perceptual origins for musical scales’, Nature Communications (2024). DOI: 10.1038/s41467-024-45812-z

̽��ֱ��tone and tuning of musical instruments has the power to manipulate our appreciation of harmony, new research shows. ̽��ֱ��findings challenge centuries of Western music theory and encourage greater experimentation with instruments from different cultures.

There are many more kinds of harmony out there

Peter Harrison

Pythagoras was wrong: there are no universal harmonies! | Cambridge research

Andrew Otto via Flikr under a CC license

A man playing a bonang

̽��ֱ��text in this work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License. Images, including our videos, are Copyright © ̽��ֱ�� of Cambridge and licensors/contributors as identified. All rights reserved. We make our image and video content available in a number of ways – on our main website under its Terms and conditions, and on a range of channels including social media that permit your use and sharing of our content under their respective Terms.

Yes

Licence type:

Attribution

Scientists find upper limit for the speed of sound

Anonymous — Mon, 12 Oct 2020 09:17:26 +0000

̽��ֱ��result - about 36km per second - is around twice as fast as the speed of sound in diamond, the hardest known material in the world.

Waves, such as sound or light waves, are disturbances that move energy from one place to another. Sound waves can travel through different mediums, such as air or water, and move at different speeds depending on what they’re travelling through. For example, they move through solids much faster than they would through liquids or gases, which is why you’re able to hear an approaching train much faster if you listen to the sound propagating in the rail track rather than through the air.

Einstein’s theory of special relativity sets the absolute speed limit at which a wave can travel which is the speed of light and is equal to about 300,000km per second. However, until now it was not known whether sound waves also have an upper speed limit when travelling through solids or liquids.

̽��ֱ��study, published in the journal Science Advances, shows that predicting the upper limit of the speed of sound is dependent on two dimensionless fundamental constants: the fine structure constant and the proton-to-electron mass ratio.

These two numbers are already known to play an important role in understanding our Universe. Their finely-tuned values govern nuclear reactions such as proton decay and nuclear synthesis in stars and the balance between the two numbers provides a narrow ‘habitable zone’ where stars and planets can form and life-supporting molecular structures can emerge. However, the new findings suggest that these two fundamental constants can also influence other scientific fields, such as materials science and condensed matter physics, by setting limits to specific material properties such as the speed of sound.

̽��ֱ��scientists tested their theoretical prediction on a wide range of materials and addressed one specific prediction of their theory that the speed of sound should decrease with the mass of the atom. This prediction implies that the sound is the fastest in solid atomic hydrogen. However, hydrogen is an atomic solid at very high pressure above 1 million atmospheres only, pressure comparable to those in the core of gas giants like Jupiter. At those pressures, hydrogen becomes a fascinating metallic solid conducting electricity just like copper and is predicted to be a room-temperature superconductor. Therefore, researchers performed state-of-the-art quantum mechanical calculations to test this prediction and found that the speed of sound in solid atomic hydrogen is close to the theoretical fundamental limit.

Professor Chris Pickard, from Cambridge's Department of Materials Science and Metallurgy, said: “Soundwaves in solids are already hugely important across many scientific fields. For example, seismologists use sound waves initiated by earthquakes deep in the Earth's interior to understand the nature of seismic events and the properties of Earth's composition. They’re also of interest to materials scientists because sound waves are related to important elastic properties including the ability to resist stress.”

Professor Kostya Trachenko, Professor of Physics at Queen Mary, said: “We believe the findings of this study could have further scientific applications by helping us to find and understand limits of different properties such as viscosity and thermal conductivity relevant for high-temperature superconductivity, quark-gluon plasma and even black hole physics.”

Reference:
K. Trachenko et al. ‘Speed of sound from fundamental physical constants.’ Science Advances (2020). DOI: 10.1126/sciadv.abc8662

Adapted from a Queen Mary ̽��ֱ�� of London press release.

A research collaboration between the ̽��ֱ�� of Cambridge, Queen Mary ̽��ֱ�� of London and the Institute for High Pressure Physics in Troitsk has discovered the fastest possible speed of sound.

PublicDomainPictures from Pixabay

Soundwave

̽��ֱ��text in this work is licensed under a Creative Commons Attribution 4.0 International License. Images, including our videos, are Copyright © ̽��ֱ�� of Cambridge and licensors/contributors as identified. All rights reserved. We make our image and video content available in a number of ways – as here, on our main website under its Terms and conditions, and on a range of channels including social media that permit your use and sharing of our content under their respective Terms.

Yes

Mice sing like jet engines to find a mate

sc604 — Mon, 10 Oct 2016 15:00:00 +0000

An international group of researchers have found that mice use a mechanism similar to that of a jet engine inside their throats in order to make high frequency whistles – the first time such a mechanism has been observed in any animal.

Mice, rats and many other rodents produce ultrasonic songs that they use for attracting mates and territorial defense. These ‘singing’ mice are often used to study communication disorders in humans, such as stuttering. However, until now it was not understood how mice can make these ultrasonic sounds, which may aid in the development of more effective animal models for studying human speech disorders.

Now, new research co-authored at the ̽��ֱ�� of Cambridge and published in the journal Current Biology has found that when mice ‘sing’, they use a mechanism similar to that seen in the engines of supersonic jets.

“Mice make ultrasound in a way never found before in any animal,” said the study’s lead author Elena Mahrt, from Washington State ̽��ֱ��.

Previously, it had been thought that these ‘Clangers’-style songs were either the result of a mechanism similar to that of a tea kettle, or of the resonance caused by the vibration of the vocal cords. In fact, neither hypothesis turned out to be correct. Instead, mice point a small air jet coming from the windpipe against the inner wall of the larynx, causing a resonance and producing an ultrasonic whistle.

Using ultra-high-speed video of 100,000 frames per second the researchers showed that the vocal folds remain completely still while ultrasound was coming from the mouse’s larynx.

“This mechanism is known only to produce sound in supersonic flow applications, such as vertical takeoff and landing with jet engines, or high-speed subsonic flows, such as jets for rapid cooling of electrical components and turbines,” said Dr Anurag Agarwal, study co-author and head of the Aero-acoustics laboratories at Cambridge’s Department of Engineering. “Mice seem to be doing something very complicated and clever to make ultrasound.”

“It seems likely that many rodents use ultrasound to communicate, but very little is known about this - it is even possible that bats use this cool mechanism to echolocate,” said the study’s senior author Dr Coen Elemans from the ̽��ֱ�� of Southern Denmark. “Even though mice have been studied so intensely, they still have some cool tricks up their sleeves.”

Reference:
Elena Mahrt et al. ‘Mice produce ultrasonic vocalizations by intra-laryngeal planar impinging jets.’ Current Biology (2016) DOI: 10.1016/j.cub.2016.08.032.

Adapted from a press release by the ̽��ֱ�� of Southern Denmark.

Mice court one another with ultrasonic love songs that are inaudible to the human ear. New research shows they make these unique high frequency sounds using a mechanism that has only previously been observed in supersonic jet engines.

Mice seem to be doing something very complicated and clever to make ultrasound.

Anurag Agarwal

diamond geezer

Clangers

̽��ֱ��text in this work is licensed under a Creative Commons Attribution 4.0 International License. For image use please see separate credits above.

Yes

Licence type:

Attribution-Noncommerical

Noises off: the machine that rubs out noise

lw355 — Wed, 02 Oct 2013 16:20:50 +0000

A noisy restaurant, a busy road, a windy day – all situations that can be intensely frustrating for the hearing impaired when trying to pick out speech in a noisy environment. Some 10 million people in the UK suffer from hearing difficulties and, as helpful as hearing aids are, those who wear them often complain that background noise continues to be a problem.

What if hearing device wearers could choose to filter out all the troublesome sounds and focus on the voices they want to hear? Engineer Dr Richard Turner believes that this is fast becoming a possibility. He is developing a system that identifies the corrupting noise and “rubs it out”.

“ ̽��ֱ��poor performance of current hearing devices in noise is a major reason why six million people in the UK who would benefit from a hearing aid do not use them,” he said. Moreover, as the population ages, a greater number of people will be hindered by the inability to hear clearly. In addition, patients fitted with cochlear implants – devices implanted into the brain to help those whose auditory hair cells have died – suffer from similar limitations.

̽��ֱ��solution lies in the statistics of sound, as Turner explained: “Many interfering noises are immediately recognisable. Raindrops patter on a surface, a fire crackles, talkers babble at a party and the wind howls. But what makes these so-called auditory textures sound the way they do? No two rain sounds are identical because the precise arrangement of falling water droplets is never repeated. Nonetheless, there must be a statistical similarity in the sounds compared with say the crackle of a fire.

“For this reason, we think the brain groups together different aspects of sounds using prior experience of their characteristic statistical structure. We can model this mathematically using a form of statistical reasoning called Bayesian inference and then develop computer algorithms that mimic what the brain is doing.”

̽��ֱ��mathematical system that he and colleagues have developed is capable of being “trained” – a process that uses new methods from the field of machine learning – so that it can recognise sounds. “Rather surprisingly, it seems that a relatively small set of statistics is sufficient to describe a large number of sounds.”

Crucially, the system is capable of telling the difference between speech and audio textures. “What we can now do in an adaptive way is to remove background noise and pass these cleaned up sounds to a listener to improve their perception in a difficult environment,” said Turner, who is working with hearing experts Professor Brian Moore at the Department of Experimental Psychology and Dr Robert Carlyon at the Medical Research Council Cognition and Brain Sciences Unit, with funding from the Engineering and Physical Sciences Research Council.

̽��ֱ��idea is that future devices will have several different modes in which they can operate. These might include a mode for travelling in a car or on a train, a mode for environments like a party or a noisy restaurant, a mode for outdoor environments that are windy, and so on. ̽��ֱ��device might intelligently select an appropriate mode based on the characteristics of the incoming sound. Alternatively, the user could override this and select a processing mode based upon what sorts of noise they wish to erase.

“In a sense we are developing the technology to underpin intelligent hearing devices,” he added. “One possibility would be for users to control their device using an interface on a mobile phone through wireless communication. This would allow users to guide the processing as they wish.”

Turner anticipates a further two years of simulating the effect of modifications that clean up sound before they start to work with device specialists. “If these preliminary tests go well, then we’ll be looking to work with hearing device companies to try to adapt their processing to incorporate these machine learning techniques. If all goes well, we would hope that this technology will be available in consumer devices within 10 years.”

Tinnitus sufferers could also benefit from the technology. Plagued by a constant ringing in the ears, people with tinnitus sometimes use environmental sound generators as a distraction. Such generators offer a limited selection of sounds – a babbling brook, waves lapping, leaves rustling – but, with the new technology, “patients could traverse the entire space of audio textures and figure out where in this enormous spectrum is the best sound for relieving their tinnitus,” added Turner.

̽��ֱ��technology not only holds promise for helping the hearing impaired, but it also has the potential to improve mobile phone communication – anyone who has ever tried to hold a conversation with someone phoning from a crowded room will recognise the possible benefits of such a facility.

Moreover, with 100 hours of video now being uploaded to YouTube every minute, Google has recognised the potential for systems that can recognise audio content and is funding part of Turner’s research. “As an example, a YouTube video containing a conversation that takes place by a busyroadside on a windy day could be automatically categorised based on the speech, traffic and wind noises present in the soundtrack, allowing users to search videos for these categories. In addition, the soundtrack could also be made more intelligible by isolating the speech from the noises – one can imagine users being offered the chance to de-noise their video during the upload process.

“We think this new framework will form a foundation of the emerging field of ‘machine hearing’. In the future, machine hearing will be standard in a vast range of applications from hearing devices, which is a market worth £18 billion per annum, to audio searching, and from music processing tasks to augmented reality systems. We believe this research project will kick-start this proliferation.”

For more information, please contact Louise Walsh (lw355@admin.cam.ac.uk).

Inset image: Dr Richard Turner

Future hearing aids could be adjusted by the wearer to remove background noise using new technology that could also be used to clean up and search YouTube videos.

We are developing the technology to underpin intelligent hearing devices

Richard Turner

̽��ֱ��Machine that Rubs Out Noise

̽��ֱ��District

This work is licensed under a Creative Commons Licence. If you use this content on your site please link back to this page.

Yes

You hymn it, we’ll play it

bjb42 — Tue, 21 Jun 2011 11:00:53 +0000

̽��ֱ��centrepiece of the music marathon will be a sound installation, called ̽��ֱ��Hours, which will be broadcast in the College's main court throughout the 24-hour period.

Interspersed with this there will be live performances, celebrating the sacred music of different world faiths, and culminating in a "Come and Sing" session on Thursday afternoon, followed by the performance of a piece by the Tudor composer, John Taverner.

̽��ֱ��entire event will be open to the public for free. Visitors can either wander into the College to experience the sound installation, or attend one of the live performances, which are listed on the College website here. ̽��ֱ��final concert will be ticketed and places should be booked by writing to music@caths.cam.ac.uk

Musical members of the public are also welcome to join in with the Come and Sing session, either by writing to music@caths.cam.ac.uk or just by turning up on the day.

̽��ֱ��event is intended to be a celebration and grand expression of the music and art produced by different religions around the world. ̽��ֱ��monastic hours - the daily order of seven gatherings for prayer - will provide a thread running through the 24 hour period, but the music used will have an inter-faith flavour.

Dr. Edward Wickham, Director of Music at St Catharine's College, who devised the event, said: "We want to express something of the way in which world religions sit side-by-side, without diluting the intensity of people's individual faiths."

"When you travel around the Middle East, you can often have remarkable musical experiences because of the proximity of one religion to another. In some cities you can hear the sound of Christian bells in one ear and the Muslim call to prayer in the other. We want to celebrate that complimentarity of musical expressions, without trying to put across any sort of glib message."

̽��ֱ��event will kick-off at 7pm on Wednesday with the premiere performance of a new piece, Luminaria, which will be performed by the St Catharine's Girls' Choir with the Egyptian soprano, Merit Ariane Stephanos.

" ̽��ֱ��Hours" itself will run continuously throughout the next 24-hour period. Co-written by Dr Wickham and Jonathan Green, the piece is a collage of sound art and live performance that has been recorded by people of different faiths from around the UK over the past 18 months, and features a tapestry of different voices, music and sounds.

Interspersed with this there will be live performances at the College by Georgian and Muslim choirs, as well as chants from the Jewish and Hindu traditions. ̽��ֱ��traditional monastic services of Compline, Lauds and Matins will all be marked over the course of the night. ̽��ֱ��event will close on Thursday with a performance of Missa Gloria tibi Trinitas by John Taverner, sung by the award-winning vocal ensemble, ̽��ֱ��Clerks.

For further details about any aspect of the event, please visit the College website here.

An epic, 24-hour celebration of religious music will be taking place at St Catharine's College, Cambridge, this week, starting on Wednesday evening (June 22).

We want to express something of the way in which world religions sit side-by-side, without diluting the intensity of individual faiths.

Edward Wickham

St Catharine's College

Detail from the event poster.

This work is licensed under a Creative Commons Licence. If you use this content on your site please link back to this page.

Yes

Power to the people?

bjb42 — Wed, 26 May 2010 08:06:04 +0000

Imagine the following situation, which may be familiar: ̽��ֱ��United States is edging towards armed conflict with an Islamic dictatorship which, it claims, is harbouring powerful weapons of mass destruction. In Britain, the Government vows to stand shoulder to shoulder with its American ally, but there is widespread protest from the voting public. As the deadline for invasion looms, the voice of the people seems to be falling on deaf ears. ̽��ֱ��country, apparently against the majority will, teeters on the brink of war.

Now imagine that this particular version of Britain has also recently undergone radical democratic reform. Thanks to the miracle of the new “e-democracy” website, any eligible citizen can have their say on the issues of the moment and the Government must abide by the wishes of the majority. On an appointed date, you log in and, along with millions of others, cast your vote on whether this war should happen. ̽��ֱ��result is a resounding “no”. British forces are stood down.

Cloud cuckoo land? Science fiction? We forget that in democracy’s cradle of Ancient Greece, the principles at play here would have been utterly recognisable. In Athens, the most famous and radical of the Greek democracies, such issues were decided by an “ekklesia”, or assembly, comprising every eligible member of the voting public. As in the imagined e-democracy, each vote cast counted for one and decision was by majority.

So if Athens, the original democracy, was so different to our own (real) system, have we, in Britain, really come to terms with what democracy means? It’s the sort of question that has clearly been bothering plenty of people since the recent General Election prompted calls for an overhaul of our allegedly “undemocratic” and “broken” electoral process. It is also a theme central to Professor Paul Cartledge’s lecture at the Hay Festival on June 3^rd.

Cartledge is A G Leventis Professor of Greek culture at the ̽��ֱ�� of Cambridge and has written a multitude of books and articles on Ancient Greece and its political thought and practice, along with many other themes. Where politicians frequently invoke democracy’s name because of its potency as an ancient, almost hallowed principle, he is at pains to point out that the Greek interpretation was radically different to our own.

“ ̽��ֱ��only real continuity between ancient and modern democracy is the name,” Cartledge points out. “In fact, the two ideas are so distinctive that it has become a real question for historians of later periods as to why democracy was chosen as the name for this new, representative system that we have now.”

̽��ֱ��Athenian ekklesia is probably the most stark example of this lack of continuity, but there are many others. Ancient Athens had no political parties, no government and no opposition. Even the body of officials which set the ekklesia’s agenda was chosen by random lottery, in which any eligible citizen (this meant male citizens who were “of age”) was potentially electable.

“An ordinary guy could get appointed to a pretty senior governmental position, or find himself as a juror in a crucial state trial,” Cartledge says. “There were some exceptions, but the Athenians were radical. They made the lottery a major political act.”

All of this certainly sounds completely alien compared with our own system. ̽��ֱ��fact is, however, that democracy has always defied clear definition. Taken literally, the term is an amalgam of two Greek words – “demos”, meaning people, and “kratos”, meaning power, but nobody has ever really been able to agree on what the ensuing “people power” should mean.

̽��ֱ��Lincolnian definition, for instance, was government of the People by the People for the People. Leninists, on the other hand, regarded it as meaning the triumph of the proletariat over a ruling elite. For a long time after the demise of the Athenian version, the term was even associable with mob rule. In 6^th century (AD) Byzantium, the word “democracy” meant a riot.

In short, when it comes to the precise meaning of democracy, the jury (however it has been elected) is very much still out. None of which has stopped modern politicians, from the leaders of our newly-installed Coalition to successive leaders of the free world, from identifying it as a symbol of human civilisation that has echoed down through the centuries thanks to the Athenian example.

Cartledge reckons that there are two reasons for this. First, the sheer audacity of Ancient Greece’s radicalism is striking even now, particularly when one considers that until then, any state system had imposed a sharp division between the masses and the ruling elite.

Secondly, Athenian democracy in particular is culturally seductive, because it coincides with some of humanity’s greatest achievements. “ ̽��ֱ��Parthenon, Pericles, Socrates, Sophocles, Plato, Aristotle… one can go on,” Cartledge says. “It’s a bit like Renaissance Florence. There was an extraordinary flowering of culture and that includes political theory.” Never mind that some of the key theorists, like Aristotle, were vehemently opposed to democracy because of its unsavoury, mob connotations.

You could argue that if our own system is indeed both different and “broken”, modern politicians could do worse than look to the Athenians for a few ideas to help them patch it up. ̽��ֱ��growing accessibility of the internet means that “e-democracy”, for example, however space-age it may sound, is increasingly feasible.

This might seem very attractive if we just imagine ourselves voting against war with Iraq. If we think of the same system applied to a nationwide vote on immigration, Europe, or the reinstatement of capital punishment, however, it becomes clear that it is more volatile than we might at first presume.

In fact, a huge gulf between us and the Ancient Athenians prohibits such acts of simple transmutation. “Their governmental system worked because it was direct and face-to-face,” Cartledge says. “ ̽��ֱ��Greeks had tiny communities of a few hundred or a few thousand; not millions.”

“One lesson you learn from Ancient Greece is that it’s not just a matter of technique but a matter of culture. For democracy to work in that form, you had to live it and understand the nuances of the different positions and issues at stake. Nowadays, for very good reasons, we privilege the world of work, or our private lives, over and above politics. It’s very difficult to be democratic.”

So why study the Greek model at all? For Cartledge, the ongoing fascination of Greek democracy is not in its role as a model for our own time, but, more subtly, the set of principles it represents.

“ ̽��ֱ��fundamental principle is a notion of equality,” he explains. “We might not be able to translate the techniques, but we can translate the ideas. What the Greeks show us is that democracy involves creating institutions that most do justice to treating every person’s contribution as politically equal.”

Using Athens as a highly distinctive point of reference helps us to ask important questions about how well our own process is representing the notion of “people power”. Some of these questions are being asked of our electoral system right now. A referendum on alternative voting certainly involves the application of one citizen, one vote, for example, but it could be argued that proportional representation would be truer still to the egalitarian principles at stake.

Cartledge believes that the lottery system used to elect officials could also be “creatively employed” in a modern context, perhaps when it comes to allocating government funds in certain cases, or the selection of an upper house. Recalling the way in which Tony Blair dealt with the invasion of Iraq in 2003, he even, (half) jokingly, wonders whether a system of selective ostracism – the Athenian process whereby a citizen who had made bad political calls could be dismissed, harmlessly, from the political community by popular vote – might work on the odd occasion.

Broadly, however, it is for lessons, ideas and warnings that we should look to the Athenians, rather than systems that we can simply plunder and claim as our own. Whether or not we ultimately go down the route of more referendum politics or dramatically change the way we vote, the merits and drawbacks of these approaches were debated ad nauseam in the Athenian assembly.

“We can’t take over Athenian democracy lock, stock and barrel, but we can use it to inform and change our perception both of their system and our own,” Cartledge adds. “They helps us to see what underlies the notions of ‘the people’, political empowerment and equality. We tend to lose sight of those ideas, because our own world is much more complex. Understandably, that means that in our own time, there is perhaps more reluctance to empower ordinary citizens than there was in Ancient Athens.”

Paul Cartledge will be speaking at the Hay Festival on June 3^rd, at 10.30am.

Greece was the birthplace of democracy, but our own political system would be unrecognisable to voters in Ancient Athens. As Classicist Paul Cartledge explains, however, that doesn’t mean that our ancient forbears have left us with nothing to learn.

We can’t take over Athenian democracy lock, stock and barrel, but we can use it to inform and change our perception both of their system and our own

Dr Paul Cartledge

D'Arcy Norman from Flickr

Democracy

This work is licensed under a Creative Commons Licence. If you use this content on your site please link back to this page.

Yes

Cambridge academics elected as Fellows of the Royal Society

bjb42 — Fri, 15 May 2009 00:00:00 +0000

̽��ֱ��new Fellows, elected for their scientific excellence, are:

Professor Ross Anderson is the Professor of Security Engineering at the Computer Laboratory. Professor Anderson is a pioneer and world leader in security engineering, and is distinguished for starting a number of new areas of research in hardware, software and systems. His early work on how systems fail established a base of empirical evidence for building threat models for a wide range of applications from banking to healthcare. He has made trailblazing contributions that helped establish a number of new research topics, including security usability, hardware tamper-resistance, information hiding, and the analysis of application programming interfaces. He is also one of the founders of the study of information security economics, which not only illuminates where the most effective attacks and defences may be found, but is also of fundamental importance to making policy for the information society.

Professor Jennifer Clack is Professor and Curator of Vertebrate Palaeontology in the Museum of Zoology. Professor Clack is a palaeontologist whose work has fundamentally changed our understanding of the origin and early evolution of tetrapods, rewriting the textbooks and revitalising the subject area. Ranging from geology through phylogenetics, anatomy and development to neuroscience, her publications document the transition from fish to tetrapods. She led the field in showing that the earliest tetrapods were aquatic and polydactylous, in describing some of the earliest terrestrial tetrapods and in tracing the subsequent evolution of skeletal and sensory systems. Her work has stimulated worldwide interest and a renaissance of collecting and research related to the fish/tetrapod transition. In 2007, Professor Clack's work was recognised by the award of the Daniel Giraud Elliot medal of the US National Academy of Sciences

Professor David Glover is the Arthur Balfour Professor of Genetics in the Department of Genetics and a Fellow of Fitzwilliam College. Professor Glover is principally known for his work in the control of the cell cycle in Drosophila. Amongst the many genes discovered by his lab are those encoding the Polo and Aurora protein kinases that are required for progression through mitosis. Glover has documented the multiple roles played by these enzymes in mitosis and cytokinesis and has helped to develop small molecule inhibitors that may prove useful for cancer therapy, since these proteins are overexpressed in certain tumours. As a postdoctoral fellow in Stanford, Glover was one of the pioneers of cloning eukaryotic DNA in bacterial vectors, and discovered the presence of introns in the ribosomal RNA genes of Drosophila.

Professor Christine Holt, a Fellow of Gonville and Caius College, is Professor of Developmental Neuroscience in the Department of Physiology, Development and Neuroscience. Professor Holt is distinguished for her fundamental studies of axon guidance and topographic mapping in the visual system. She initiated the analysis of guidance and mapping in living embryos. She demonstrated the accurate targeting of the earliest retinal axons, and pioneered the dynamic imaging of axons and growth cones. She revealed the molecular basis of pathway choice at the chiasm, demonstrated the context dependent response of growth cones to guidance molecules and showed that local protein synthesis and degradation are essential to growth cone steering. She has identified the molecular basis for the dorso-ventral axis of Sperry's retinotectal map.

Professor David Mackay, a Fellow of Darwin College, is Professor of Natural Philosophy in the Department of Physics. Professor MacKay introduced more efficient types of error-correcting code that are now used in satellite communications, digital broadcasting and magnetic recording. He advanced the field of Machine Learning by providing a sound Bayesian foundation for artificial neural networks. Using this foundation, he significantly improved their performance, allowing them to be used for designing new types of steel that are now used in power stations. He used his expertise in information theory to design a widely-used interface called "dasher" that allows disabled people to write efficiently using a single finger or head-mounted pointer. He is the author of the critically acclaimed book, "Sustainable Energy - without the hot air", which sets out the various low-carbon energy options open to us.

Professor Wolfram Schultz, a Fellow of Churchill College, is Professor of Neuroscience in the Department of Physiology, Development and Neuroscience and Wellcome Trust Principal Research Fellow. He has been the most influential electrophysiologist working in the area of the reward and reinforcement in the last decade. He discovered that dopamine activity, rather than being directly related to movement, is driven by rewards and reward predicting stimuli. Moreover, he has established that the profile of activity in a variety of behavioural paradigms demonstrates that the dopamine neurons encode not simply the occurrence of the reward but rather the prediction error generated by the reward. This important finding has had a major impact on contemporary theories of learning and reinforcement. His more recent work suggests that dopamine activity may also encode an aggregate signal of reward magnitude and probability, thereby providing a critical input into economic decision processes.

Professor Henning Sirringhaus, a Fellow of Churchill College, is the Hitachi Professor of Electron Device Physics in the Department of Physics. Henning Sirringhaus is distinguished for his work on semiconductor device physics and engineering. Early in his career, at the ETH Zurich, he pioneered the technique of ballistic electron emission microscopy. At Cambridge he has transformed the field of organic semiconductor transistors from curiosity to fully manufacturable technology through both fundamental science and engineering. His insights into the polaronic nature of electron states in these materials and the control of interfacial structure made possible large increases in field-effect carrier mobility. His work on novel processing methods, including ink-jet printing, has made possible new manufacturing methods. A recent highlight is his realisation of a light-emitting field-effect transistor.

Professor John Todd, a Fellow of Gonville and Caius, is Professor of Medical Genetics at Cambridge ̽��ֱ�� and Director of the Juvenile Diabetes Research Foundation/Wellcome Trust Diabetes and Inflammation Laboratory in the Cambridge Institute for Medical Research. Todd is distinguished for his research on the genetics of common complex disease. In work spanning 20 years, he has pioneered theoretical and experimental approaches that have allowed him to resolve many aspects of the inheritance of type 1 diabetes. His elucidation of the molecular basis of the major gene effect in type 1 diabetes, together with his results from genome-wide analyses, have recently culminated in his successful dissection of the genetic architecture of type 1 diabetes, revealing a multiplicity of susceptibility genes converging on an aetiology of common, quantitative alterations in immune regulation.

Professor Burt Totaro is Lowndean Professor of Astronomy and Geometry in the Department of Pure Mathematics and Mathematical Statistics. ̽��ֱ��central part of Burt Totaro's work has been devoted to the interaction between two of the major areas of pure mathematics, topology and algebraic geometry. Inspired by the Hodge conjecture, Totaro has worked to unc

over the fundamental topological structure of algebraic geometry. Each step has made possible the solution of a well-known problem in algebraic geometry and demonstrated that progress towards the Hodge conjecture will come through topology. Totaro's work has influenced a large group of algebraic geometers to use deeper topological methods in their work. His ideas have also had unexpected payoffs in a wide variety of other mathematical fields, including representation theory, Lie groups and group cohomology.

Nine of the 44 new Royal Society Fellows announced today are Cambridge academics. Their election to the Fellowship of the Royal Society recognises their exceptional contributions to society. As Fellows of the UK's national academy of science, these leaders in the fields of science, engineering and medicine join other famous Cambridge names such as Isaac Newton, Charles Darwin and Stephen Hawking.

yudis_asnar from Flickr

King's College Cambridge

This work is licensed under a Creative Commons Licence. If you use this content on your site please link back to this page.

Yes

Virtual violins

tdk25 — Mon, 01 Sep 2008 00:00:00 +0000

Violins crafted 300 years ago by the master violin-maker Antonio Stradivari sell for millions of pounds on the rare occasion they reach auction; what is it about their quality of sound that makes them prized above all others? Indeed, is their sound actually discernibly different? Any experienced violinist knows that some violins respond to their bow better than others: what determines which violins are difficult and which are easy to play? Questions such as these have fascinated musicians and scientists since the 19th century.

To get to the heart of the riddle there is an added complication: sound is in the ‘ear of the beholder’. In fact, although much is now known about the acoustics of the violin, and how this is influenced by the way it is made, virtually nothing is known about how human capacities for perceiving, discriminating and judging violin sounds match up to their acoustical features. This is a very significant gap, as perceptual judgements obviously define what makes a violin different from, say, a cello, just as it makes one violin different from another, for listeners, performers and violin-makers alike.

A three-year project funded by the Leverhulme Trust that is reaching completion at the ̽��ֱ�� of Cambridge has been intent on filling this gap. ̽��ֱ��approach has involved collaboration between four departments – Professor Jim Woodhouse from the Department of Engineering, Dr Claudia Fritz and Dr Ian Cross from the Faculty of Music, Professor Brian Moore from the Department of Experimental Psychology and Dr Alan Blackwell from the Computer Laboratory.

Strings and body

̽��ֱ��tone, pitch and loudness of a violin are the product of many components: drawing a bow across tightly stretched violin strings forces them into complex harmonic vibration; a significant fraction of this acoustical energy is transmitted, via a structure called the bridge, into the violin body. Here, the sound is amplified by the vibration of the wooden box and the air inside it.

̽��ֱ��team’s approach relies on the fact that the acoustical behaviours of the strings and the violin body can be treated separately, and that it is the latter that distinguishes different violins. In fact, on its own, a string makes hardly any sound and the acoustical behaviour is much the same from one instrument to another. ̽��ֱ��main acoustical feature that ‘colours’ the sound in ways that are unique for each violin is the way in which the violin body responds to the different frequencies input from the bridge and radiated from the body. This characteristic transformation is known as the violin’s ‘frequency response characteristic’.

Virtual violins

̽��ֱ��first stage of the project was to create a ‘virtual violin’. To carry out any comparative study of musical instruments it is important to rule out variations caused by the player. Instead of achieving this by using a robotic violinist that repeats the same piece on a variety of real violins, in this project the tests themselves are virtual.

Sensors on a violin bridge record the string waveforms arising as a player performs normally. ̽��ֱ��recordings are stored as standard force functions, which can then be applied to different violins to hear how they sound without having to worry about any complications caused by variations in playing. So, by ‘playing’ these recordings through computer models of different violins’ frequency response characteristics using digital filters, a prediction of the sound of the violin can be created. This makes it possible to ‘play’ exactly the same performance on different ‘virtual violins’. ̽��ֱ��frequency response characteristics can be derived from empirical measurements made on a range of real violins.

̽��ֱ��psychoacoustics of the violin

Once the violin response is represented in digital filter form, it becomes very easy to make controlled variations of a kind that would be almost impossible to achieve by physical changes to a violin. This gave the researchers an opportunity to focus on what features of violins’ response characteristics determine how listeners discriminate between different violins. In particular, the psychoacoustical experiments looked at just-noticeable differences of alterations made to the acoustical response characteristics of two violins: an excellent violin made by David Rubio and a mass-produced student violin that was informally rated as low quality. Psychoacoustical test methods can be used to find the threshold for detection of any particular change, and also to obtain statistically significant data on quality judgements made by the listeners.

Using groups of listeners that spanned expert string players, expert non-string-playing musicians and non-musicians, it was found for both instruments that the alteration of individual low-frequency resonances needs to be fairly large in order to be perceptible. Even for the listeners who were expert players, a resonance needed to be shifted (in terms of frequency) by about a semitone to be perceptibly different. However, if several resonances are shifted simultaneously, a smaller shift becomes audible.

Testing timbre

̽��ֱ��sound of an instrument is not just about pitch and resonance but is also about a somewhat elusive quality known as timbre. It is, in effect, the richness of the sound. Similar to the manner in which a wine taster conveys the flavour and aroma of a fine wine, there are many different descriptors for the timbre of an instrument: from ‘warm’, ‘sonorous’, ‘clean’ and ‘free’, to ‘unbalanced’, ‘heavy’, ‘dull’ and ‘dead’. In fact, a data-mining exercise from ̽��ֱ��Strad, a classical music magazine covering string instruments, came up with a list of 61 words that are commonly used by players, critics, makers and listeners to describe the quality of the sound.

This list of descriptors was used as the basis for a series of experiments in which players located the words in two-dimensional spaces, the results being analysed by multidimensional scaling methods (MDS) to produce maps of families of terms. Some relevant descriptors can therefore be selected on the basis of their distribution in the MDS spaces. This is now allowing the team to test timbre in a more methodical way than has been possible before, asking questions such as: does an increase of amplitude in the frequency range between 650 Hz and 1300 Hz really make the violin sound more ‘nasal’?

Probing the mysteries of music

̽��ֱ��aim is to provide researchers, violin-makers and repairers with an evidence-based means of assessing what it is necessary to adjust on a violin to achieve improved sound. This rigorous analysis of descriptors and their relations will not only be useful to specialists in discussions with performers, but will also have pedagogical value and might lead to new ways for composers and arrangers to annotate musical scores. Perhaps one day, when describing how one violin sounds different to another, we will be able to say exactly why.

For more information, please contact the author Dr Claudia Fritz (cf291@cam.ac.uk) at the Faculty of Music.

Why does one violin sound different to another? Investigating this question has brought together researchers from music, engineering, experimental psychology and computer science.

̽��ֱ��aim is to provide researchers, violin-makers and repairers with an evidence-based means of assessing what it is necessary to adjust on a violin to achieve improved sound.

firepile on flickr

Violin

This work is licensed under a Creative Commons Licence. If you use this content on your site please link back to this page.

Yes