SciBar is science in a bar - an invited speaker gives a talk on a scientific topic while people enjoy a drink or meal, with a Q&A afterwards. Bollington SciBar takes place at the Vale Inn in Bollington. 

Speaker in October: Trevor Cox, Professor of Acoustical Engineering, University of Salford

Topic: Room acoustics is about bringing physics and psychology together to make spaces where speech and music sound great. Acousticians try to engineer out problems such as echoes from domes or excessive reverberation. But after a trip listening to strange sounds in a sewer, Professor Trevor Cox set out to find, explain and celebrate acoustic 'defects'. He documented them in his book Sonic Wonderland.

The science behind the whispering gallery in St Paul's in London, was solved around a century ago. Other historical examples like the sound of Echo Bridge in Massachusetts have only recently had the physics explained. Some have suggested that Stonehenge should have extraordinary sounds due to the concave arrangement of the stones, but measurements on a 1:12 acoustic scale model show this is unlikely. Mathematicians use billiards to explore dynamical systems but real-life audio examples are rare. One documented by Trevor is the abandoned Thurgoland railway tunnel near Sheffield, which has an extraordinary metallic flutter arising from closed orbits.

Remarkable architectural sound effects usually arise by chance, being an accidental by-product of geometry. Using prediction models, we can explore what sound effects could be created if designers deliberately set out to maximise acoustic aberrations. The acoustic phenomena play with our perception of sound: in the spherical radome on top of the disused Cold War spy station at Teufelsberg near Berlin, you can whisper into your own ears. Our trip will end in the disused World War II oil tank which Guinness awarded with the record for the 'longest echo'. Play a note on a saxophone in the space, and the sound lingers for over a minute before dying away!

No charge, all welcome. Vale Inn, Adlington Road, talk begins 6.30pm - arrive early as seats often fill very quickly.