Foam Grades

It is a well known fact that using acoustic foam in your studio will improve the sound quality of your studio. you need to be informed on some basic facts about foam and what is acoustic foam and “Why is acoustic foam so expensive?” ( truth told it isn’t ).

Polyurethane Acoustic Foam Polyether and Polyester

Polyurethane foam is made in two main types polyester and polyether both of these types of foam are manufactured by the large chemical foam manufacturing companies to grades designed for acoustic applications. These are tested to see if they meet the correct noise reduction coefficients that set them apart from other foam grades. The determining factors of the foams physical structure that will set it apart are the foams density, porosity, hardness and a regular cell structure, the right combination will ensure you have the right foam grade suitable for acoustic applications.

Where did Acoustic Foam Technology Come From

Most acoustic foam grades are derived from foam grades that were developed to be used for automotive applications where the reduction of sound was a major consideration. These foam grades do have a premium on price compared to other foam grades, but not as much as you think. The main reason acoustic foam is sold at a high price is simply added mark up and high profit margins.

Why is Acoustic Foam so Expensive

The vast majority of acoustic foam sellers are simply reselling foam they have had cut by someone else and resold at hyped up prices. All your acoustic foam will have been manufactured by large foam manufacturing and conversion companies. and then sold on to the acoustic foam resellers who in turn have the added costs of transport storage warehousing distribution promotion marketing and their own profit margin to add on..

Pro-Acoustic Foam

The Pro Acoustic range is made from a specifically formulated acoustic foam grade in a 25kgm3 foam we chose this as it outperformed other grades we had tested, the two main polyether acoustic foam grades being a 25kgM3 ( which has a density range of 25 to 27 kilos per m3) and a 28kgm3 ( which has a density range of 28 to 30kgm3) many sellers call this grade 30 kilo to always air on the heavier side as they will try an say the heavier the foam the better its acoustic properties “Absolute Rubbish” heavier doesn’t make it a better acoustic foam. Look for the NRC data on the tiles to ensure you are getting a foam product to deal with the acoustic issues you need to attend to. This article compares our Block 45 tile with another similar sized 30 kilo tile sold in the same price range

Furniture Foam is not Acoustic Foam

Do not take much heed to the spin that manufacturers use furniture foam passing it off as acoustic foam, why would a large manufacturer use a foam grade not suited to the products application. if you were a clothing manufacturer would you buy a roll of thick blue denim to make a thin white cotton shirt? you buy the grade needed for the application. Its Simple. Acoustic foam re-sellers will often use this type of shallow scare mongering as a vein spin to discredit companies who manufacture and sell direct as obviously they can drastically undercut their prices.

Specifically Formulated Acoustic Foam

In our factory we only use Specifically formulated grades of foam developed for acoustic applications. We do not make furniture products and the only other grey foam used in our factory apart from the acoustic foam grade we buy is also a specialist foam that is for medical bedding applications and is a high density 41 kilo high resilience foam with a totally different cell structure. being 41 kilo per m3 it is far more expensive per M3 than any standard acoustic foam grade. whether 25 or 28 kilo.

Acoustic Foam The Most Popular Room Treatment

Acoustic foam has become the treatment material of choice for many home music producers for a number of reasons however the top three reasons are;

Acoustic foam offers great absorption for mid to high end frequencies.

Acoustic foam is relatively more affordable compared to high end options.

Acoustic foam is easy to handle and shape into aesthetically pleasing and performance enhancing shapes.

Acoustic Foam Types Polyester Polyether and Melamine

Broadly speaking, there are three types of foam used for acoustic applications. These are, in order of increasing price.

Polyurethane polyether foam

Polyurethane polyester foam

Melamine foam

Polyurethane polyether acoustic foam grades

Polyurethane polyether foam has a large range of applications and comes in a very limited range of densities and colours. Acoustic applications are best suited to densities between 25kg/m3 up to 30Kg/m3 this is quite a limited scope as density range within a block of foam itself can alter by 2 kilos per m3 being heavier at the bottom of a block compared to the top. This is why only 2 specific acoustic polyether foam grades are used in the UK these are 25kilo 25 to 27kilos per m3 and 28 kilo 28 to 30 kilos per m3. and in all honesty there’s not much between them. Look for the NRC test data on a tile its the only real measure of the products performance.

Acoustic Foam Colour Why not White

The reason acoustic foam is dark grey coloured as these foam can discolour with time ( look up “phenolic yellowing” it is the anti oxidants used in polyurethane foam manufacture reacting against pollutants in the atmosphere) darker colours age gracefully. Also consider the fire rating used on the foams UL 94 HF1 is an automotive based fire rating test. as mentioned above most acoustic foam was developed for automotive applications. It falls far short of the tests needed to ensure the foam is suitable for use in a building not only should the foam meet UL 94HF1 it should also the Furniture and Furnishings British standards, look to see if the foam grades meet this test acoustic foam fire test and means you are not taking chances in your studio.

Polyurethane polyester foam grades

Polyurethane polyester foam grades are also very good of acoustic foams again being derived from the automotive field , and come at a premium price which reflects their manufacturing process. The way in which Polyester foam is manufactured gives it a very regular cell structure which make it very good as and acoustic foam. the main difference is that polyester foam can be flame bonded to fabric and is used for applications such as the headlining’s in cars. because of this it is often cut very thin as this makes the regular the cell structure is very important.

Polyester acoustic foam grades lends its great performance to the greater percentage of open cells meaning more air pockets exist which soak up the energy of sound waves. Polyester foam is manufactured in blocks and tested for air resistance at intervals to ensure that the performance is uniform which ever part of the block is used. This precision led manufacturing process means that polyester foams aren’t riddled with blow holes leaving a shiny aesthetic surface that delivers performance time after time.

Polyester foam grades provide controlled absorption across the entire spectrum with thicker foams offering effective absorption down to 125Hz right through to the top end of the frequency spectrum. This wide band of performance means polyester foam grades are the choice for professionals looking to introduce absorption into their studios. Polyester foam can also take longer to discolour when compared to their polyether counterparts, again this is all down to the pollutants in an atmosphere reacting with the foams anti oxidants. look up phenolic yellowing to see more on this.

Melamine Foam grades

Whilst not traditionally used in music studios melamine foams are fast gaining recognition as an acoustic treatment option for studio acoustic treatment. Priced higher than polyester and polyether foams melamine foam offers the perfect combination of absorption and light weight. This type of foam is currently mostly made by BASF in germany and sold under licence under the name Basotech.

Melamine foam grades achieve this extraordinary feat by exhibiting a true 3D filament structure. This structure means that melamine foam doesn’t have any closed cells but rather millions of air chambers which significantly increase its performance in the mid to high frequencies. Although thicker panels will shift the absorption down to the lower end of the spectrum for domestic purposes the cost doesn’t justify the performance.

So where then does melamine foam come in handy? The answer is simple. Firstly the extremely light weight nature of these foam grades means that melamine foam panels can be stuck on to ceilings of large buildings without any concern of the impact on roof loading. This property means that melamine baffles and blocks are used in large building, factories, gymnasiums, churches and swimming pools.

Secondly melamine foam grades are available in brilliant white and is the only type of foam which holds its colour without getting discoloured when exposed to the atmosphere. This lends it well to use for indoor applications where darker coloured tiles would present an aesthetic challenge. Melamine panels are handy for home cinemas and used for treating walls and ceilings at reflection points as well as treating home studios that double up as work offices.

Melamine foam grades can be cut into a number of shapes although most popular are flat panels with beveled edges. Melamine comes in standard White, grey and light grey however the white panels may be spray painted using specialist equipment to any colour.

Finally melamine foam is class 0 fire rated which is lends it well to applications where building regulations mean only materials with high fire ratings can be used without impacting on the aesthetic of the room it is applied to. Other foams can be treated to make them class 0 rated but this involves impregnating them with graphite and carbon which results in black sheets. Not exactly the best for indoor use.

Melamine foam grades are however quite brittle and can easily get damaged so needs to be handled with caution.