Frequently Asked Quentions
Elastomers for Noise and Vibration Control, Shock Protection and Ergonomics (manufactured by EAR) /  Absorbing Foams

• By what mechanism does acoustical foam absorb noise?
• Acoustical foam transforms kinetic energy of air vibration generated effectively into thermal energy through viscosity of air. TUFCOTE series acoustical foam is a foam with open cell construction and closed cell construction mixed to facilitate airflow intake and interference. (Apart from that, noise may be reduced by the use of interference.)

• What kinds of noise may be absorbed?
• It absorbs high-pitched noise, and may effectively absorb middle-pitched noise If combined with noise barrier. As it is very difficult to absorb low-pitched noise, it is necessary to take appropriate actions to find out the cause of such low-pitched noise and solve the problem.

• What is needed for effective use of acoustical foam?
• It absorbs high-pitched noise, and may effectively absorb middle-pitched noise If combined with noise barrier. As it is very difficult to absorb low-pitched noise, it is necessary to take appropriate actions to find out the cause of such low-pitched noise and solve the problem.

• What is needed for effective use of acoustical foam?
• As the air vibration attenuates little by little every time it passes through acoustical foam, it is important to design so that it has to pass through the material many times reflecting repetitively.
  Noise may leak through even a small clearance if any. So, if it is necessary to have an opening, it must have such construction that noise may not easily come out reflecting at internal wall around it.

• What happens without absorber? (with barrier only)
• Noise energy accumulates within the closed volume, and gradually transforms little by little into thermal energy due to viscosity of air until it reaches equilibrium. If combined with absorber, it accelerates transformation of noise energy into thermal energy.

• Are there any other methods available?
• • Glass wool: Viscosity of air that vibrates and moves insides the glass wool helps transformation into thermal energy, which contributes to absorption of noise.
  • Piercing holes in wall: Viscosity of air that vibrates and passes through holes helps transformation into thermal energy, which contributes to absorption of noise.
  • Providing conical protrusion to wall surface: Change in direction of reflection increases opportunity of interference and helps transformation into thermal energy, which results in noise reduction.

• Does the absorber thickness affect performance?
• Noise has a wavelength. High-pitched noise wavelength is short while low-pitched noise long. It is therefore necessary for an absorber to have such thickness that may catch the wavelength effectively.

• What noise may be effectively absorbed?
• Noise higher than 200 Hz should be targeted.