This is but the sketchiest outline of oustanding lives that Molleson brings to the fore so vividly. Not all of the music that she talks about is easily available to listen to but there is a fairly decent range of material on Spotify to accompany the reading and give you some idea of what these remarkable characters achieved. She portrays a world of exceptional compositional talent that, had it been given rightful prominence, would have enriched and expanded the domain of modern classical music beyond measure. And I would assume that it’s by no means just an historical problem although thankfully, these days, we have scholars and broadcasters like Molleson to continue the work of redressing the balance. Moved more to centre-stage instead of consigned to the margins, who knows what amazing music might develop? Radio Three should give her her own weekly show in which to feature the lives and work of these marginalised and fascinating composers. It might not always make for easy listening but, as she so clearly argues, their story and their work deserve to be heard and integrated into a long-overdue revisionist appraisal of the music of our time.

Main article: Speed of sound U.S. Navy F/A-18 approaching the speed of sound. The white halo is formed by condensed water droplets thought to result from a drop in air pressure around the aircraft (see Prandtl–Glauert singularity). [12] Applications of acoustics are found in almost all aspects of modern society, subdisciplines include aeroacoustics, audio signal processing, architectural acoustics, bioacoustics, electro-acoustics, environmental noise, musical acoustics, noise control, psychoacoustics, speech, ultrasound, underwater acoustics, and vibration. [3] Definition Newly published by Faber, Kate Molleson’s ‘Sound Within Sound: Opening Our Ears To The Twentieth Century’ reaches towards a more expansive definition of classical music, writes Andy Childs.The speed of sound depends on the medium the waves pass through, and is a fundamental property of the material. The first significant effort towards measurement of the speed of sound was made by Isaac Newton. He believed the speed of sound in a particular substance was equal to the square root of the pressure acting on it divided by its density:

Sound Within Sound makes us realise that there was so much more music out there by people like her, plus music that was never finished, written down or performed. It also focuses our ears on the brilliant stuff that survives, encouraging us to dig deeper and keep listening. When sound is moving through a medium that does not have constant physical properties, it may be refracted (either dispersed or focused). [5] Spherical compression (longitudinal) waves As the human ear can detect sounds with a wide range of amplitudes, sound pressure is often measured as a level on a logarithmic decibel scale. The sound pressure level (SPL) or L p is defined as Molleson has employed her expert knowledge and refined perspective in selecting which ten artists to include in what, in less discerning hands, could have been an unwieldy, daunting tome. She has chosen ‘ten beautifully messy, confounding, brave, outrageous, original and charismatic composers’. Each one of these elegantly written biographical essays describes a remarkable, singular, creative life, strewn with political, social and domestic obstacles. They describe a fierce commitment to their art, a refusal to compromise and a determination to write whatever music they pleased. They are wonderful characters, if apparently not all easy people to get along with.

Sound that is perceptible by humans has frequencies from about 20Hz to 20,000Hz. In air at standard temperature and pressure, the corresponding wavelengths of sound waves range from 17m (56ft) to 17mm (0.67in). Sometimes speed and direction are combined as a velocity vector; wave number and direction are combined as a wave vector. This was later proven wrong and the French mathematician Laplace corrected the formula by deducing that the phenomenon of sound travelling is not isothermal, as believed by Newton, but adiabatic. He added another factor to the equation— gamma—and multiplied Physics Experiment using two tuning forks oscillating usually at the same frequency. One of the forks is being hit with a rubberized mallet. Although only the first tuning fork has been hit, the second fork is visibly excited due to the oscillation caused by the periodic change in the pressure and density of the air by hitting the other fork, creating an acoustic resonance between the forks. However, if we place a piece of metal on a prong, we see that the effect dampens, and the excitations become less and less pronounced as resonance is not achieved as effectively. Sound pressure is the difference, in a given medium, between average local pressure and the pressure in the sound wave. A square of this difference (i.e., a square of the deviation from the equilibrium pressure) is usually averaged over time and/or space, and a square root of this average provides a root mean square (RMS) value. For example, 1 Pa RMS sound pressure (94 dBSPL) in atmospheric air implies that the actual pressure in the sound wave oscillates between (1 atm − 2 {\displaystyle -{\sqrt {2}}} Pa) and (1 atm + 2 {\displaystyle +{\sqrt {2}}} Pa), that is between 101323.6 and 101326.4 Pa.