A city hall is a space in which, especially for medium and high frequencies (therefore, in particular: in the 500-2000 Hz frequency range):
- the sound level can be very high, because of the activities taking place there
- the noise can become troublesome with respect to activities such as relaxation, discussion
Such symptoms of a lack of acoustic comfort can often be directly related to excessive reverberation of the considered space, the results of measurements made then indicating that the internal acoustics is perfectible by the means of specific soundproofing means such as those studied and marketed by ITS in the field of sound insulation in buildings.
The human resource of ITS has extensive experience in the selection of materials and soundproofing products to improve the acoustic comfort of premises, whatever the type of building considered is (the sizing is generally based on acoustics calculations predictions, and the on-site result, if the installation is entrusted to a partner company, is subject to a guarantee); of course, the acoustic properties must be considered, but other technical characteristics must be the subject of an in-depth examination on a case-by-case basis e.g. the fire behavior (in terms of flammability and non-harmfulness of the fumes), the weight with regard to what is acceptable for the supports, and, in general, the methods of implementation.
The success of such projects of soundproofing in the construction sector is depending on all these aspects, and on other considerations relating in particular to decoration and cost.
ITS will participate in the soundproofing of a city hall, near Chatillon sur Chalaronne in the department of Ain (France - Auvergne Rhône-Alpes region) for which reverberation time measurements had shown poor quality of building acoustics.
This is not uncommon for such a public place which is made available to the inhabitants by a municipality for festive or cultural events, but it is nonetheless problematic, e.g. in terms of speech intelligibility and sound environment, a fortiori when considering the use of amplified music, the discomfort in terms of acoustics being able to be quite simply unbearable (in the case of an orchestra: as well for the spectators as for the musicians [1]).
A limitation of the amplification of sound levels will be achieved by the implementation of absorbent materials in the form of suspended ceiling panels for this city hall (their sound absorption coefficient, will constitute the ultimate for the frequency interval corresponding to the human voice, being equal to 100%, which corresponds to an absorption class A). .
No doubt that this treatment will significantly improve the acoustic comfort of this place used both for association meetings, receptions, banquets, entertainment and various events as well as for amplified music broadcast.
[1] the risks of occurrence of the Larsen effect (physical phenomenon of acoustic feedback between a loudspeaker and a microphone of an audio system, when the sound emitted by the transmitter is picked up by the receiver which retransmits it amplified transmitter, with a gradual increase in sound levels linked to whistling), are increased in such contexts - being, needless to say - highly undesirable