Acoustics: What is it? 

Have you tried having a conversation in a room filled with people, where, despite your strenuous efforts, it is impossible to hear what the other person is saying? 

That's acoustics. 

Or, to clarify, it's bad acoustics. 

Control and reduce the sound 

In short, acoustics is how sound travels in a room.

And to learn more about the acoustics this is what we need to dive into. So, what is sound?

Sound is sound, you might think, but no, not in the world of acoustics 😉

Sound is, in other words, the soundwaves that are created from e.g. our voices when we speak. It's these soundwaves that we want to "calm down" to avoid too much sound. If the soundwaves does not meet a surface that can absorb the sound, but only meets hard sound reflecting surfaces, like a living room wall, the sound waves will reflect back and be "thrown around" in the room. 

This is how unpleasant acoustics are created.

Technically a long reverberation time, also known as echo, is created and it's this - the reverberation time -  that's the star of creating good acoustics. 

Picture:
First - the sound meets a sound absorbing surface.
Second - the sound meets a hard surface and is reflected back. 

Example: If you have a conversation in a room with a long reverberation time, the first word you say will not die out before the next word reaches the listener. This means that the words will mix and it will almost be impossible to have a conversation. 

Technical speaking: Reverberation time and the alpha-values 

The acoustics are thereby determined by the reverberation time. 

The reverberation time is determined by how many seconds it takes the sound to drop 60 dB after the sound has stopped. The perfect reverberation time depends on the size of the room, the interior and the intended use of the room. 

This means that the perfect reverberation time will differ in the living room, the kitchen, the children's rooms and so on.

In our everyday life we of course do not consider how many seconds it takes for the sound to drop. But we consider and notice if we can't hear what our daughter is saying over dinner or if we keep needing to adjust the volume on the TV because the perfect volume does not seem to exist. 

The perceived reality is therefore just as important as the one we can measure.

And both are dependent on the sound being absorbed by different elements in the room.  

It's all about the balance 

So, the acoustics are sound that we want to calm down. 

To make sure this happens we need to add elements that can do just that - reduce the reverberation time.  

In theory, all objects and surfaces reduce the reverberation time, as the soundwaves will lose some of their energy when meeting a surface, it just depends on how much and whether it's sufficient to reduce the reverberation time enough to create good acoustics. This is determined by the object's sound absorbing properties, which are described by the alpha-value (0-1). 

A rule of thumb is that we want sound absorbing objects to have an alpha-value as close to 1 as possible as this means that all sound that meets the object is absorbed. 

A sound absorbing object can e.g. be our DAMPA® Silent Board, which has an alpha-value of 0.95. 

But, DAMPA, if all sound in the room is absorbed won't it be an unpleasant experience to be in? 

Yes, you a perfectly right. 

It is important to mention that the sound fans out, and it will only be some of the e.g. spoken sounds that hits the sound absorbing objects and are absorbed. This is why it is important to consider the placement of the acoustical objects. 

However, the acoustics are not only determined by the acoustic objects in your room. It is also determined by things like your decor and interior. Do you have a sound absorbing ceiling? Do you have many soft elements like pillows and blankets? 

All of this also affects the reverberation time. 

Click here and read more about how you should place your acoustic panels and how many you need.

To sum up: Acoustics are not easy 😅 and if you have any questions regarding acoustics, acoustic panels or likewise please do not hesitate to contact us at hello@dampa.dk