ARCC BU REVIEWER PART 5 (Acoustics)

From recorded lecture video (2024)

CHB Wall

This is the most economical material to insulate sound inside a room/reflect sound around a room

Reflection

An acoustic phenomenon where resultant sound energy returned from a surface that is not absorbed or otherwise dissipated upon contact with the surface (leads to echoes)

Refraction

An acoustic phenomenon where there is a change in the direction (along with speed and/or wavelength) of waves as they pass from one medium to another.

Diffraction

An acoustic phenomenon where there is bending of the travel of sound caused by an obstacle in its path; being of waves around small obstacles and the spreading out of waves beyond small opening

Diffusion

An acoustic phenomenon where sound reflects off a convex or uneven surface that spreads/disperses it so that it is less direct

Absorption

An acoustic phenomenon where sound is absorbed by soft materials

hard, smooth, and plain

Sound reflects off _______ surfaces (e.g. reinforced concrete, granite stone)

The back wall of the room/wall facing to the speaker

In a classroom/auditorium setting, the surface of this object should be soft—so that sound doesn’t reflect back from here to the speaker in front

Reflective materials

Classrooms, auditoriums, boardrooms, and courtrooms all need spaces with this type of acoustic materials.

Low ceilings

This feature in auditoriums are the reason why back rows can still receive reflected soundwaves despite their distance from the front

Soft surfaces

Cinemas are equipped with these types of surfaces (e.g. cloth, fabric) that absorb intense sound coming from its sound systems.

Absorptive Materials

Cinemas, open offices, home theaters, conference rooms, and recording studios all commonly need spaces with this type of acoustic materials.

Diffusive materials

These are hard materials with convex/concave, uneven, or rough surfaces, typically used in performance centers, operas, and home theaters.