82
edits
Changes
Jump to navigation
Jump to search
Line 19:
Line 19: + − + − + Line 30:
Line 31: + +
→Sound patterns: I added needed subsections, and wrote another paragraph based on more of the same source.
Reverberation is sound echoing and reechoing. Wallace Sabine measured reverberation in a lecture hall using a stopwatch. He then measured the effect of sound absorbing materials such as seat cushions. He found they reduced the duration of the reverberation. <ref name="Stevens & Warshofsky Chapter One" />
Reverberation is sound echoing and reechoing. Wallace Sabine measured reverberation in a lecture hall using a stopwatch. He then measured the effect of sound absorbing materials such as seat cushions. He found they reduced the duration of the reverberation. <ref name="Stevens & Warshofsky Chapter One" />
==Sound patterns==
==Sound patterns==
===Beat===
“Beat” is when two slightly different frequencies of sound waves combine to cause a sound with rising and falling loudness. This is because when waves are in the same place they join and become a bigger wave and when they are between each other they cause a flat “surface.”<ref name="Stevens & Warshofsky Chapter One" />
“Beat” is when two slightly different frequencies of sound waves combine to cause a sound with rising and falling loudness. This is because when waves are in the same place they join and become a bigger wave and when they are between each other they cause a flat “surface.”<ref name="Stevens & Warshofsky Chapter One" />
===Reflection===
“Reflection” is when sound waves bounce off a flat surface. “Plane reflection” is when the sound bounces off a flat surface at an angle equivalent to the angle it came at the surface, like a ball bouncing off the side of a pool table. “Parabolic reflection” is when the sound bounces off a curved surface and disburses like the beam of light from a flashlight. “Elliptical reflection” is when the sound bounces off a curved surface and focuses on a point at some distance from the origin of the sound. For example, if one whispers on one side of the room, the sound is focused by the elliptical surface and the whisper can be hear at a point on the other side of the room.<ref name="Stevens & Warshofsky Chapter One" />
“Reflection” is when sound waves bounce off a flat surface. “Plane reflection” is when the sound bounces off a flat surface at an angle equivalent to the angle it came at the surface, like a ball bouncing off the side of a pool table. “Parabolic reflection” is when the sound bounces off a curved surface and disburses like the beam of light from a flashlight. “Elliptical reflection” is when the sound bounces off a curved surface and focuses on a point at some distance from the origin of the sound. For example, if one whispers on one side of the room, the sound is focused by the elliptical surface and the whisper can be hear at a point on the other side of the room.<ref name="Stevens & Warshofsky Chapter One" />
===Refraction===
“Refraction” of sound is when sound waves change direction because of a change in what they are traveling through.<ref name="Stevens & Warshofsky Chapter One" />
“Refraction” of sound is when sound waves change direction because of a change in what they are traveling through.<ref name="Stevens & Warshofsky Chapter One" />
A larger refraction causes a reflection. When the warm air is a lot warmer than the cooler air, the sound bounces off of the warm air heads back toward the ground – still moving away from the source of the sound. When a man yells on a winter morning on one side of a lake, the sound waves might bounce off the sky and be heard on the other side of the lake, but not in the afternoon when the ground is warmer.<ref name="Stevens & Warshofsky Chapter One" />
A larger refraction causes a reflection. When the warm air is a lot warmer than the cooler air, the sound bounces off of the warm air heads back toward the ground – still moving away from the source of the sound. When a man yells on a winter morning on one side of a lake, the sound waves might bounce off the sky and be heard on the other side of the lake, but not in the afternoon when the ground is warmer.<ref name="Stevens & Warshofsky Chapter One" />
===Interference===
“Interference is when sound waves bump into each other, decreasing the quality of the sound. Sound waves are areas of high followed by low pressure or closeness of molecules. The high areas are compressions and the low are rarefactions. When the compression of one wave fills in the rarefaction of another, the volume is lowered. When two compressions join, the sound is unnaturally louder. The sound waves of a tuning fork interfere with each other to some extent. If the tuning fork is turned while sounding, the volume rises and falls from interference. "Dead" spots in auditoriums are caused by sound waves canceling each other, causing the volume of those spots to be less.
== Subcategories of Sound ==
== Subcategories of Sound ==