Evolution Dome – a sound case for noise reduction
We have just completed independent acoustic testing of our inflatable domes and the results show a substantial drop in noise across the 700mm wall of our inflatable structures.
We have always received compliments from clients that our inflatable structures provide good sound insulation from whatever noise is generated outside the structures. Whilst this is always nice to hear we decided that we needed to test this so that we could provide customers with hard evidence as to exactly what frequencies were dampened and by how much.
To retain objectivity, the tests were carried out by sound engineer, Dick Crabbe, of Ease Audio. A signal of pink noise was fed to a loudspeaker at the centre of the structure, and a measurement was taken 5m outside the dome.
The results show a good reduction of sound across the inflatable structure walls but the most noticeable drop was in the upper range of frequency, the ones most encountered in settings with conversation and the general noise of business.
The diagram shows a green trace, taken 2m from the loudspeaker inside the dome, recording a level of 86dB. The purple trace was taken outside, at a level of 68dB. It is notable that there is much less sound reduction through the structure at lower frequencies, typically about a 6dB reduction. However, in the range of the human voice, this increases to about 12dB reduction. This reduction is typically thought of as being about half as loud. In the vocal clarity range, needed for intelligibility, that reduction increases to around 20dB.
As the research shows, the structures are less likely to reduce the deep sounds of a bass guitar or kick-drum, but for those intrusive frequencies that can make conversations difficult in high-traffic areas of an event, the reduction is significant.
The report is available for download from the Evolution Dome website .