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Open Office


Sounds Of Science - SOFSCI - Voice energyTo work in an open office where sound absorption is nonexistent, or at best poor, is not a very pleasant experience. Especially not if you are supposed to think while working: Which most jobs today require.
An open office environment is filled with many different kinds of sound, all of which needs to be dealt with, absorbed. It can be anything from fans working to footsteps to conversations between co-workers to phone calls being made. Therefore we have the whole register of frequencies, from the lowest to the highest, and all those creates echoes, or reverberations, bouncing back and forth.
The first thing is to ask ourselves where absorbers would do the most good and the answer is probably close to the source and where the primary echoes are being created. That is, beside and above work spaces and other sound emitters such as pathways. With wall panels on the walls closest to the work space and ceiling panels above you will find that most of the echoes are taken care of and that the acoustic environment becomes a more pleasant one:
Good and functional sound absorbers placed where it counts really makes a difference. However, buying some pieces of nicely designed felt or cloth and hanging them on the walls here and there will not help you very much. No matter if the manufacturers say that they absorb sound or not all it does is leave a big hole in your wallet while your co-workers are just as troubled by the acoustic environments as before – resulting in stress and unhealthiness. By now you know that they need to absorb both high and low frequencies and in order to do that they need to be constructed out of a hearty amount of absorbing material, not fastened directly on the wall or ceiling but with a good air column in between.
The same thinking as with open offices applies to restaurants, hospitals, museums, hotel lounges, shopping centers and any other space that many people share which has multiple sound sources and usually very echoic.
The human voice has a range of between 300 and 3000 Hz, therefore we need sound absorbers that are effective within these ranges. And especially in the lower range for this is where the most energy is.
As you can see in this graph the most energy in the human voice is actually around 300 Hz, which is quite low.
Most products aimed for conference rooms, open offices and similar are fairly ineffective on the lower part of the voice bandwidth and thus they only manage to absorb the higher parts: leaving the user with a bad acoustic environment.  The absorbers should be placed in such a way that the primary echoes are the first points of attack. That is, they should be placed on the walls and in the ceiling.

What works then?

There are lots of products on the market, aimed for the Open Office market, that are usually quite pretty to look at. Usually they also cost quite a lot of money. Problem is they don´t work. If you put a piece of felt directly to the wall then this is quite useless. Same thing with sound absorbing paintings that are usually around three centimeters thick and sits directly on the wall or has plywood or similar on the back. This is not adequate when it comes to dealing with human speech - products like this removes the higher frequencies but nothing else. Thus leaving all the lower frequencies bouncing back and forth, actually creating a worse acoustic environment than before it was hung on the wall. Have a peek at our animation for more info about sound and sound absorption.