Hi,
In continuation to the previous Blog. We had mentioned that Acoustic language also has it’s own ABCD – Where A is absorption, B is Block, C – is Cover (Noise Cancellation) and D – is Diffusion.
Today we will talk about absorption
When a place is too echoic or too live, we need to reduce this echo, reverberation, liveness by introducing absorptive materials.
How much of the area will require absorption treatment will depend on material used for absorption. Cushions, bedding, pillows, sofa, curtains all contribute in absorption. However, the level of absorption varies. Absorption capabilities of materials is measured in NRC (Noise Reduction Coefficient). NRC can be minimum value of 0 (means 100% reflective) or maximum value of 1.
The amount of acoustic material to be installed will depend on the NRC value of the material. A material having value closer to 1 will be required lesser in quantity and a product having value closer to 0 will be required in more quantity.
There is a science in calculation of reverberation in a room if a dimension of the space is known and material used is also known.
There are also certain equipments we use which are highly calibrated and require a high end software to measure and record the reverberation in a room. I will write a very short blog on the process of measuring the reverberation, STC etc. Once we complete our blog on ABCD of Acoustics.
Some Materials used for Absorption are
Glasswool (Banned in many countries)
Rockwool(Banned in many countries)
Melamine foam,
Open Cell PU,
Closed Cell PU,
Whisper Foam,
Wood wool Boards,
PET Panels(Preferable to use ones with less plastic)
There are many more products. Which to select depends on which frequencies are problematic in your space, what purpose the space would be used for, how many years you want it to perform, is moisture expected in the space and so on.
In the future blogs, we will try to discuss each material in detail. However, before that we will also try to understand role of sound frequencies too.
In the next blog we will discuss B- Block or isolation