ITS participated in improving the sound environment of a noisy restaurant near Saint-Denis de la Réunion (France).

This constituted, once again, an opportunity to contribute to the resolution of a fairly recurrent problem of acoustic discomfort in spaces such as the one considered in the context of this project.

Indeed: that a restaurant is noisy and that its sound ambiance leaves something to be desired is a commonly observed reality, whether it is a question of places that one frequents by pure need to sustain oneself (canteen, refectory, self-service, company or community restaurant) or places that are chosen with a view to combining what is usefull (eating) and what is pleasant (having a good time, finding an environment calm enough to encourage discussions or conviviality for festivities e.g. celebration halls); the literature does not lack illustrations of such situations, as already reported elsewhere in this blog [1] [2] [3], and as mentioned - in connection with a brasserie which has been a high place of Parisian life since almost a century - in the book by the French writer Eric Zemmour - France has not said its last word "The immense hall of the Coupole resounds with a brouhaha that forces us to raise our voice. » [4]

It is of course highly undesirable for everyone wishing to be heard - and finding it difficult to do so - to speak louder (i.e. to increase the acoustic power of their voice), because the resulting chain reaction mechanism, which is uncontrollable, is very detrimental to the sound ambiance (this is commonly referred to as the "Lombard effect"), and leads to nothing other than an increase in discomfort on an acoustic level, concomitant with the rise in sound levels (since the noise is itself increased), which is counterproductive in the perspective of obtaining a sufficiently quiet ambiance.

As on the occasion of the quote above, "brouhaha" is often the word used to describe a sound environment that leaves something to be desired in a restaurant (including: when it is fast e.g. in bars , pubs, cafeterias); synonyms e.g. “hum”, “hubbub”, “hurly-burly”, “tumult” are used in different contexts often referring to other spaces.

To avoid this (sometimes: to prevent this, sometimes to remedy this), one of the aspects of the acoustic insulation of buildings that should not be neglected for restaurant rooms is the reverberation control, which requires the implementation of sound-absorbing materials :

  • in sufficient quality i.e. with a sound absorption coefficient as close as possible to 100% at medium-high frequencies (i.e. in the 1/1 octave frequency bands centered on 500 Hz to 2 kHz), corresponding (for humans) :
    • to maximum ordinary human sound emissions (foreign legion songs and opera songs not included ?)
    • to maximum average hearing sensitivity
  • with a sufficiently homogeneous distribution in the considered space (and of course: in sufficient quantity, with regard to its volume)

This is precisely what can be made effective by the implementation of screens with high sound absorption such as those marketed by ITS, for the improvement of the sound ambiance of noisy restaurant rooms within the framework of this project.

Another mode of action of these soundproofing dividers, which is decisive for the noise reduction, is the screen effect (i.e. the ability to oppose the propagation of noise towards a specified location) which is induced by their installation, which depends on the relative positioning of the noise source (in this case: a speaker at a given table) and the point of reception (a seat, at a neighboring table - for the user of a canteen or the customer of a restaurant -), the dimensions of the acoustic screen and also the properties (in terms of sound absorption) of the adjacent surfaces (e.g. the ceiling, a fortiori when it is low). What results (and which is important in terms of subjective evaluation of the sound ambiance of a restaurant):

  • discretion: this is the situation obtained when an effort is required to understand the content of a conversation which is generated; then the conversation is not a distraction
  • confidentiality: this is the situation obtained when even with an effort to understand a conversation which is generated, it remains incomprehensible

Thus, among the means for the improvement of the sound ambiance of a noisy dining room [5], the soundproofing screens marketed by ITS occupy a place of choice, since combining the two fundamental functionalities in terms of acoustics that limitation of reverberation and increase in spatial sound decay are [6].

In addition, they have recognized advantages :

  • their modularity and their mobility: they adapt to all premises layouts
  • their decorative feature: they embellish the space (i.e. they also improve the visual atmosphere), the color chart offering, for the surfacing of the sound-absorbing material (of course: incombustible) shades all more shimmering than the other
  • their durability

Moreover, they can be combined, for an even greater improvement in the acoustic quality of some spaces (for noise limitation) such as restaurants (this was not the case in the context of this project) with sound-absorbing wall linings and sound-absorbing suspended elements perfectly matching i.e. made with the same filling material and with comparable structural elements.

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[1] Marketing of acoustic screens for noise reduction in premises requiring soundproofing
[2] Noise reduction in a dining room to improve acoustic comfort
[3] Improved restaurant acoustics for noise limitation
[4] (Rubempré, 2021 page 166)
[5] also: for other premises that are noisy or likely to be noisy, in some contexts e.g. collective open spaces, offices and reception desks for the public in public buildings, activity rooms in nurseries and in other spaces accommodating children
[6] with regard to the acoustic quality of buildings and premises such as restaurant rooms, the usual measurable performance indicators are the reverberation time - usually expressed in seconds, per frequency band - and the spatial noise decay rate - in dB(A) by doubling the distance to a sound source