Generally speaking, the thickness of the current sound-absorbing panels is 3-24mm. 9mm and 12mm are more commonly used. 1 to 3mm is generally called felt.
There are also sound-absorbing panels with a thickness of 25mm and 50mm. However, due to the increased thickness, the density is made small. Usually 25mm and 50mm are made of sound-absorbing cotton, with a density between 600GSM and 1000GSM.
The density of the 9mm board is thicker at 1900GSM, and the thinner is between 1000GSM and 1900GSM.
The density of sound-absorbing panels with a thickness of 12mm is between 2000GSM and 2400GSM.
The density of sound-absorbing panels with a thickness of 24MM is around 3800GSM.
If you have strict requirements on the sound absorption effect, you can choose a thicker board. For example: 12mm or 24mm board. Or a combination of 3mm sound-absorbing felt and 12mm sound-absorbing panels.
The specific thickness and form can be selected according to your own requirements.
Generally, a board with a sound insulation of more than 30dB is called a sound insulation board. Made of high density material. The specific thickness, size and density can also be customized with the manufacturer.