Everything you need to know about acoustic foam!
It is important for you to know what makes a good acoustic foam, so that you are not misled by the many offers found online.
Sadly, there is a lot of misinformation in this sector, and we repeatedly see people being wrongly advised and incorrect information being provided in product descriptions. Once fitted, you cannot return the foam and you have to live with the result; even if different materials would have provided a better solution.
As such, it is worth spending five minutes to find out how to differentiate between a good and a poor acoustic foam, and where it is better to to opt for a lower-priced foam rather than an expensive acoustic foam. You will also discover how foams can contribute to an improvement in sound quality, and how you can insulate walls effectively.
What exactly is "acoustic foam"?
Strictly speaking, the term "acoustic foam" is an invention of the industry – upholstery foam or even a mattress have acoustic effects due to the open porosity of the foam. However, you cannot use these types of foam to systematically solve acoustic problems; or rather, we don't know what the end result would look like.
There are no measurement tables with frequencies etc., and no empirical values for forum discussions, as you are unlikely to find someone who has placed a mattress against the walls of their recording studio. Acoustic foams have been specially designed for the acoustics segment, and come with different surfaces, panel thicknesses, weights, porosities, colours and profile/base ratios. Depending on the issue, tested foams are used or recommended to specifically solve the problem.
There are two basic acoustic applications: reverberation reduction within rooms, or sound insulation or noise insulation between rooms – i.e. preventing sound from passing through solid surfaces, for example in a badly sound-proofed flat or a badly sound-proofed waiting room (and also for insulating machinery, compressors, etc. in the technical sector). This is soundproofing (within a room) and sound insulation (between two rooms, for example). To find out more, please click on The difference between soundproofing and sound insulation.
What acoustic material do I need to resolve my issue?
If you want to reduce the reverberations in a room:
...you will need e.g. convoluted foam or pyramid foam (please note that these profiled foams only tend to reduce higher frequencies), or, even better, flat absorbers without any profiling, which can absorb sound across all frequencies and are also effective in the lower frequency range. Convoluted foam and pyramids are, therefore, found frequently in recording studios and music rooms where only very specific frequencies are to be eliminated. In contrast, flat absorbers are best used in areas in which as much sound as possible is to be absorbed, such as in offices, bars, waiting rooms, bowling alleys, nurseries, schools, universities etc.
Absorbers with a comparable panel thickness will always absorb far more sound than convoluted or pyramid foams of an equivalent thickness. It is also important to pay attention to the level of fire protection provided by the acoustic foams – it must comply with the level of protection that you need or want on site. We have various products with different fire protection levels. Our Basotect acoustic foam is in line with the highest standard here, for example, and can generally be used anywhere (if in doubt, always check on site). We stock all of these products.
The idea that profiled surfaces are needed to dampen noise is a fallacy. It is the panel thickness that is decisive, and not the surface area of individual panels, as many claim. Data provides clear proof of this. Many people mistake the surface of a panel with the overall area of the room in m² that is to be covered! The total area laid does, of course, have an important effect on total absorption. The more that is laid, the less reverberation you have.
Along with these classical profiled or non-profiled panels there are specialists, such as bass absorbers or broadband absorbers, which absorb in the low-frequency range in particular. It is also not essential to use rectangular panels to reduce reverberation – you can use circular, oval or star-shaped panels, or panels in any other shape. The decisive things are the panel thickness and the total surface area of the ceiling in m² that is to be absorbed. We also offer acoustic images or ceiling sails and movable partitions for offices. Our online assistant addresses many standard problems together with our recommendations for products, quantities, panel thicknesses etc.
If you want effective sound insulation...
...you won't get far with convoluted foam or pyramid foam. Pyramid and convoluted foam are wrongly recommended in the field of insulation again and again; they may have an effect, but it is risible in comparison with more suitable materials. To insulate correctly – whether it is a room wall, a machine or a motor – you need heavyweight flat absorbers. Because only mass and panel thickness are able to effectively prevent sound waves from spreading or passing through walls.
Our products in the category Sound insulation fall in this area. Here you can find dense acoustic foams, such as our very popular composite foam in various thicknesses, as well as other supporting materials, such as bituminous foil or bituminous felt, which also insulate sound effectively, or deaden metal surfaces. It contains all the information you need if you are looking for effective insulation. We have also produced our own wall insulation kit, which can be used to insulate walls retrospectively (e.g. walls to neighbours).
How can I identify the quality of a foam?
Not just by the product description! In the case of professional retailers, you can also tell based on the price. It may sound strange at first, but that's how it is. All retailers do essentially the same thing, and the basic components, e.g. for PU foam, are the same all over the world. You can produce the convoluted or pyramid foam cheaply or to a higher grade with more or with better quality foam; or, with profiled foams, you can leave a thin base and cut the naps or pyramids very high – this saves material, but considerably reduces the effect.
The problem is that in both cases the product is sold as "convoluted foam" or "pyramid foam". As such, you can assume that very low prices that are far below the average are almost 100% guaranteed to mean poor quality foam that will not be up to much acoustically – unless the retailer is running a sale and reducing the prices, meaning a real bargain for you. Unfortunately, there is also another situation: some retailers demand an exorbitant price for poor or mediocre foam – this may be due to the retailer's storage costs, or because they are not specialists, or because their turnover is not very high and along with foam they sell flowers and postcards, or they sell foam as a marginal product and just a few sales at a high price are sufficient.
That is why we generally sell various qualities of the most common acoustic foams. Our solid Eco quality (cost-effective but not cheap!); our very high-quality MicroPor foam with very fine porosity, very good absorption and a flame-retardant finish; and our high-end product made of Basotect, which has excellent absorbing properties, does not readily ignite and does not turn yellow.