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Inventor of decibel scale4/12/2024 ![]() ![]() When multiple experiments could no longer be denied, Newton finally fudged the theory to produce the measured number. They tried over and over, they attempted to account for every variable, they resurveyed the distance across the open fields, and still they could not get their measurement to agree with theory, Finally, unable to find a flaw in Newton’s theory and unable to account for their measurements, they abandoned the work while Newton held firmly to his published sound speed. To their utter mortification they found Newton’s prediction to be 20% slow. They watched through a telescope at the Greenwich observatory as a cannon was fired at Shooter’s Hill, three miles (4.8 km) away. Newton’s friends John Flamsteed (1646-1719 the first Astronomer Royal) and comet-discoverer Edmond Halley (1656-1742) measured the speed of sound to confirm Newton’s triumph. In his 1687 book Prlncipia Mathematica, Newton predicted the speed of sound using the new calculus to create a purely mathematical analysis. Gassendi used a mechanical timepiece, and it was he who discovered that the high-pitched crack of a musket and the boom of a cannon arrived at the same time and realized that all pitches travel at the same speed. Mersènne used a pendulum to measure the time between the flash of exploding gunpowder and the arrival of the sound. ![]() The earliest actual measurements were made by Pierre Gassendi (1592-1655) and Matin Mersènne (1588-1648). Later, a tree would be found exploded to bits and burnt to ash, locating the exact target of the lightning, ![]() This was demonstrated every time a flash of lightning was followed by the crack of thunder. In prehistoric times people knew sound traveled more slowly than light. The new mathematical techniques created a huge, powerful machine for processing and analyzing experimental results, but these exercises usually took place in a curious vacuum: there were no experimental results to test them against. Yet, the one simple statement that sound does this or that was not forthcoming. Now we had formulas for densities and elasticities, displacements of strings, superposition and propagation, plates and shells - they march page after page after hundreds more pages and endless thousands of equations through Lord Rayleigh’s Theory of Sound. In 1863 an anonymous author in Philosophical Transactions of The Royal Society wrote, “Hearing may be divided into direct, refracted, and reflex’d, which are yet nameless unless we call them acousticks, Diacousticks, and catacousticks.” The word was needed because at precisely that moment natural philosophers (or scientists, as in the 19th century they would begin to style themselves) needed a word for the experiments they were beginning to conduct.įinally, in the second half of’ the 17th century the invention of calculus created, almost overnight, a revolution in our understanding and study of sound propagation. Francis Bacon (1561-1626) used it in his 1605 book Advancement of Learning. It came to English from the French, to which there is a problematical derivation from the Greek. The experimental means to disprove this theory were readily available, but no such experiments were performed for two thousand years, and even then experimenters withheld their contradictory results for fear of being spurned, ridiculed, or ostracized.Įven the word for this science cum art - acoustics - comes from elsewhere. In fact, until the 17th century natural philosophers thought it absolutely illogical to make any attempt to quantify it or even theorize about its measurement.Īristotle (384-322BC), working from ancient researches into theater design, reasoned that high pitches must travel faster than lower pitches. In order to understand today’s sophisticated computerized measurement systems and place their capabilities in perspective, it is useful to examine, from historical and scientific perspectives, the technological developments and systems that gave birth to the science of audio measurement.įor centuries it was thought that sound was so ephemeral that any attempt to capture it - to hold a ruler against it - would be a fruitless exercise. Today’s technology enables investigations into the finest detail and structure of sound and audio signals. For four centuries, natural philosophers and scientists have sought to quantify and derive qualitative standards for sound. ![]()
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