With regard to the comments made above, these are generally expensive in comparison with their acoustic worth.
They should only be used where flexibility or ease of installation is important.
They may also be used as damping material.
For instance a metal panel in a car may vibrate and transmit energy to the passenger compartment.
If it were damped, then not only would the vibration would be reduced, but significant energy would be taken out of the sound wave.Come on the FREE COURSE TOUR