reflected off a surface, usually one which is hard, rigid and/or flat.

sound waves absorbed into a material upon contact; change of sound energy into some other form

occurs when sound waves are dispersed equally in a room

acoustical phenomenon which causes sound waves to be bent or scattered around such obstacles as corners, columns, walls, beams, etc.

change of sound wave direction as it moves from one medium to another of different density

sound which penetrates through a surface

the prolongation of sound as a result of successive reflections in an enclosed space after the source of sound is turned off

sound travels at 1130 ft. per second or 344 m. per second at normal room temperature (68°F); sound travels faster in denser media.

rate at which sound energy is being transmitted, measured at any point in the medium; intensity diminishes inversely as the square of the distance.

the unit in which sound intensity is defined for architectural purposes

instrument by which sound intensity is measured

the fluctuation in the atmospheric pressure caused by the vibration of air particles due to a sound wave.

subjective attribute of an auditory sensation in terms of which sounds may be ordered on a scale of soft to loud.

minimum intensity that is capable of evoking an auditory sensation in the ear.

minimum sound pressure level which stimulates the ear to a point which is painful

the number of displacements or oscillations that a particle undergoes in 1 second.

the attribute of an auditory system which enables us to pinpoint sounds on a scale extending from high to low frequency.

sound sensation having pitch.

the distance a sound wave travels during each complete cycle of vibration measured in meters or feet.

sound sources radiate sound waves in all directions; radiation pattern varies with the frequency; high frequency sounds are more pronounced along the longitudinal axis of the sound source.

if heavy, it can act as a reflecting surface

may change the direction of sound

can also act as a reflecting surface

particles of sound tend to follow cold air

sound waves which have been reflected to a listener with sufficient magnitude and time delay so as to be perceived separately from those communicated directly from the source to the listener.

similar to echo except that the time delay between the perception of direct and reflected sounds is somewhat less.

a rapid succession of noticeable small echoes observed when a short burst of sound is produced between parallel sound reflective surfaces.

sound reflections from concave surfaces concentrating in an area sometimes referred to as hot spots. The intensity of sound at hot spots are always at the expense of dead spots.

sound reflections from concave surfaces concentrating in an area sometimes referred to as hot spots. The intensity of sound at hot spots are always at the expense of dead spots.

two rooms adjacent to each other by means of open doorways, with at least one space being highly reverberant.

an undesirable change in the quality of musical sound due to the uneven and excessive sound absorption of the boundary surfaces at different frequencies.

also called Coloration. Occurs when certain sounds within a narrow band of frequencies tend to sound louder than other frequencies.

occurs when an area does not receive an adequate amount of direct and reflected sound.

high frequency sounds creeping along large concave surfaces such as a hemispherical dome.

bonus