In terms of price, acoustic blankets beat acoustic foam hands down.
Even at the first glance, one can see a huge difference in price versus efficiency:
(NOTE: For ease of comparison, we compare all products to NRC 1.0 as a 100%, not absorption of blankets (NRC 0.8). For example absorption of 1” foam is 50% (NRC 0.5) and absorption of blankets 80% (NRC 0.8). Therefore, 1 inch acoustic foam is 30% less absorptive and less efficient than acoustic blankets.)
- 1” acoustic foam is 30% less efficient than sound blankets but it is 5 times more expensive.
- 2” acoustic foam is 5% less efficient than sound blankets but it is more than 8 times more expensive.
- 3” acoustic foam is only 10% more absorbent than sound blankets but it is 12 times more expensive.
- 4” acoustic foam is 30% more absorbent than sound blankets and is 16.3 times more expensive. (Just imagine how many blankets you can get for that money!)
Practical Use
Ease of use is important, but it is difficult to quantify.
Acoustic foam comes in different colors and is trendy – looks cool. It is light and easy to stick to a wall or a ceiling. Unfortunately, once it is glued to a wall, it is not movable. It is too fragile and easy to tear to be able to peel off the wall to reuse elsewhere. Over time, the foam accumulates dust and disintegrates. We did not find any specific research to quote, but logically, acoustic foam performance has to deteriorate overtime as well.
Perfect for acoustical issues — such as on-stage performances in bars and other in-door settings.
Acoustic foam is an open-cell porous material. The open cells are the opening of long twisted tunnels.
To get absorbed, the sound has to get into the openings and flow through the tunnels, losing energy through friction. This is one of the reasons that sound foam has wedges – to increase the overall absorbing surface of the foam. But, this serrated edge, at the same time, makes acoustic foam a great dust collector!
Porosity and the flow resistivity are the most important parameters in determining the sound absorption. Imagine if the pores, or the openings of those tunnels, get clogged by dust — sound cannot get in, and therefore, sound absorption efficiency is reduced. Regardless of how thick the foam is or how well the tunnels are twisted, if the opening of those tunnels get blocked – the sound can not get it and, and therefore, sound absorption will be reduced.
Sound absorption mechanism of acoustic blankets is different. It is based on the sound waves spending their energy on vibrating the fibers of the inside filler. The sound gets in and goes through the blanket. As each fiber vibrates, sound energy gets lost by converting into heat.
Blankets do not need to be glued to the wall. In fact they are more effective when there is an air gap between the wall and the blanket. Acoustic blankets make it very easy to create a vocal booth or dedicated recording space simply by hanging the blankets off the ceiling. This makes acoustic blankets an irreplaceable sound absorption choice when there is lack of space, living arrangement in a rental property or anticipation of frequent moving from one location to the other. If the blankets get dusty or dirty, they can be easily be taken off – shaken up and/or washed.
Any way you look at it, acoustic blankets are more efficient, less costly and a healthier product than acoustic foam.
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