PSYCH 3A03 Lecture Notes - Particle Displacement, Sound Energy, Reverberation

• School: McMaster University
• Department: Psychology
• Course: PSYCH 3A03
• Professor: Paul Faure

Document Summary

A point source transmits sound energy as an ever expanding spherical wave front. Acoustic power is radiated equally in all directions. As sound sphere expands, the total energy emitted from the source becomes distributed over an exponentially increasing spherical surface area (sa) Distance from the sound source can aid us to measure the amplitude to measure the surface area of a sphere. The total power (watt) of the source equals the intensity times the sphere"s surgace area (i x sa) The amount of energy per square meter on a sphere"s surface decreases by 1/r2 (r = radius of sphere) Energy at twice the distance from the source is spread four times the area and thus has one-quarter the intensity. At 2x distance from source (2r), intensity is that at source distance (r). Intensity is related to pressure: intensity proportional to pressure2. At 2r pressure will be ( ) or that of the source.