An analytical model for calculating the minimum space between restaurant tables in order to attenuate the Lombard effect

Abstract

Food establishments have the main need in the scope of acoustics to allow customers to talk at a normal voice level. Some psychoacoustic phenomena, such as the Lombard effect, can directly impact the acoustic comfort of the place. Many surveys and studies have being showed that noise, in addition to all the health issues it can be related, can have a big impact on restaurant finances. Some models to quantify the number of costumers a restaurant can hold simultaneously were proposted before, but no study concerning the miniminal distance between tables was found for the same topic. Here, an analytical model is proposed to calculate the minimum space between tables in order to attenuate the Lombard effect. The model uses as an approach the difference between the useful acoustic energy density (from a table conversation) and the disturbing acoustic energy density (from neighboring table conversations), linked to a value of signal-to-noise ration (SNR). The model allows the analysis of different styles of food establishments, ranging from the calmest and most intimate to the busiest and noisiest. Scenarios can be designed for different levels of acoustic conditioning, translated by the average absorption coefficient (a¯) of the place. A comparison between analytical model results and IMMI-simulated results proved the analytical model provides consistent results. The distance between tables depend on room parameters, but in general, results can be satisfactory and practicable, especially in establishments planned to be more calm and intimate.