In the article ” What are good acoustics?”, we described how hard surfaces create a long reverberation time and unpleasant acoustics. But how can metal, which has a reflective surface, be the main element in our acoustic solutions?

The answer to this question is (almost) simple.

Acoustic absorbents

By making perforations in the metal’s robust surface, our products activate all three absorbent types: porous-, membrane-, and resonance absorbent. Since 1951 we have created acoustic solutions of high quality by combining all three absorbent types.

To better understand how our metal ceilings and wall panels can be acoustic, we will have a look at the different absorbent types.

Porous absorbent

A porous absorbent consists of fibres, which start to move when they are hit by sound waves. The sound waves will in this process be stopped and converted to heat through the moving fibers.

An example of places, which are filled with porous absorbents are clothing shops. Where one would experience different sounds and acoustics in other shops, the clothes (or porous absorbents) will lower the reverberation time significantly and make the shop a pleasant place to shop and stay.

The porous absorbent is effective in high-frequency areas such as whistles, computer devices, screaming, glass breaking or nails on a chalkboard, but not the lower.

Membrane absorbent

A membrane absorbent is created in the space between two slabs. An example is the membrane absorbent created in the space between the unperforated area of our wall panels and the wall.

The air in the underlying space works as a spring and together with our metal sheet, it constitutes a swinging system, which constantly searches to neutralize the sound waves.

This absorbent is a contrast to the porous absorbent and is most effective in low-frequency areas, sounds such as severe weather, sound waves that often sound “lower’ to the human ear, “rumbly” sounds that you feel as just as much as you hear.

Resonance absorbent

The last absorbent type is the resonance absorbent, which is a development of the above-mentioned membrane absorbent. The resonance absorbent is also using the hard surface, however this time it is the perforation and its edge which is the main element.

In these holes, you will find “air plugs”, which, when they are hit by sound waves, will make vibrations, which will be affected by the air or porous materials in the underlying space. The air or the porous material will work as a spring, which seeks to calm down the vibrating “air plugs”. This vibrating system is created by the energy of the sound waves, and therefore the sound is no longer reflected in the room.

Just as the membrane absorbent this absorbent is most effective in the lower frequencies.

The best from the acoustic world

In our acoustic metal solutions, we achieve the best acoustic experience by using a perforated metal surface combined with a porous absorbent e.g., our acoustic felt. When combining these three different absorbent types we can create an acoustic solution customized to the use of the room and the user’s needs.

Robust acoustic solutions

It is not only because of the acoustics that metal is an ideal building material. By exploiting the metal’s robust qualities, it is possible, even in the bustling areas, to achieve long-lasting solutions – this is both an advantage for the planet and the operating budget.

At the same time, it is a hygienic material, which makes our acoustic solutions to walls and ceilings ideal for hospitals, children’s institutions, schools, restaurants and many more places, as it can easily be cleaned and wiped off.

Furthermore, the metal surface gives you total freedom to design the surface as you wish, whether it is colourful or with digital print.

Metal and sustainability

Metal and sustainability do not often appear in the same sentence. When metal is produced from new it is a heavy material to extract, it uses a lot of energy and produces a lot of waste. However, when the metal is produced it can, with relatively few resources, be recycled 100 % without leaving the circular orbit. At DAMPA we respect the materials and are always securing the right waste sorting at source, so we can secure that the material does not cease to exist.

Read more about our sustainability work.

Takeaways from the article

• By making perforation in the metal, we can activate all three acoustic absorbents
• A Porous absorbent consists of fibres, which start to move when hit by sound waves and this way stops the sound. For example clothes, carpets, curtains etc.
• A membrane absorbent is created in the space between two slabs. The air in the space works as a spring, which neutralizes the sound waves.
• The resonance absorbent is created in our perforation, where “air-plugs” make vibrations when hit by sound and calm down the sound waves.
• When combining all three absorbents we can create an acoustic solution, which is perfectly matched to the use of the room and needs of the users.