MUSI 3702 Lecture Notes - Lecture 8: Standing Wave, Infrasound, Psychoacoustics
25 May 2016
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Musi 3702: introduction to the acoustics & psychoacoustics of music. Absorption sound waves are absorbed by a material. Reflection sound waves can bounce off surfaces. Refraction direction of wave changes because of the medium. Interference is when two or more waves interact (constructive and destructive interference) Standing waves occur when two continuous waves interact. Infrasound: low-freq sound, lower in frequency than 20 hz, the normal human hearing. *temperature has the largest effect on speed of sound in air* During the day, the lower the altitude the higher the temperature. During the night, the lower the altitude the lower the temperature. *sound waves are always bending in the direction of the cooler air because sound waves bend in direction of slower medium* The decibel (db) scale is a logarithmic scale, not a linear scale. If the noise source is doubled, the noise level only increases by 3 db. Decibels are based on the power of 10.
