Types of Absorptive Materials 5

Question 1

The particles are interlocking and act by converting sound energy into heat
- better absorption for high frequencies
- E.g. fiberglass, mineral wool, glass wool, acoustic tiles, acoustic blanket, etc.

Answer 1

Porous Absorber

Question 2

Panel or membrane absorbers are constructed from fixed sheets of continuous materials within a space behind them; the space may be of air or may contain porous absorbent.
-The panels absorb the energy of sound waves by converting them to mechanical vibrations in the panel which, in turn, lose their energy as friction in the clamping system of the panel.
- Better absorption for low frequencies
- -E.g. plywood and hardboard paneling, gypsum boards, suspended plaster ceilings, blurred out plasters, rigid plaster boards, windows, glazing, doors, wood floors and platforms, etc.

Answer 2

Panel Absorber

Question 3

They consist of an enclosed body or air confined within rigid walls and connected by a narrow opening (called the neck) with the surrounding space in which the sound waves travel.
-A cavity resonator of this type will absorb maximum sound energy in the region of its resonance frequency.
-An empty jar bottle, also acts as a cavity resonator; however, its maximum absorption is confined to a very narrow frequency band (specific frequencies).

Answer 3

Resonator