Acoustic treatment of a conference hall: to ensure a proper audibility at medium and long distance

Acustica Sala Conferenze Pannelli fonoassorbenti

Project: Large conference hall with seats on steps
Room size: 780 m³
Acoustic problem: High reverberation timesdue to the height of the place

In a conference hall, acoustic comfort is a fundamental requirement for a good listening quality at medium and long distance. The DIN 18041:2004-05 standard, in fact, establish the acoustic quality criteria of places by dividing them in two groups, A and B, according to the listening level required. Group A, audibility at medium and long distance; group B, audibility at short distance.

The proposed acoustic correction project concerns a conference hall with rectangular layout; the volume of the hall is about 780 m³. During the design phase, the functional needs of the place have been studied and then, a phono-metric analysis has been carried out to calculate the reverberation time before the acoustic treatment and the results achievable after the installation of Caruso Acoustic sound-absorbing panels.

The result was an average reverberation time (Rt) of 2,745 s, with empty room. According to the DIN standard and given the volume of the place concerned, the achievement of a reverberation time of 1.13 s at an average of 250-2000 Hz has been set as a goal to ensure the proper acoustic comfort in the hall.

Distribuzione pannelli fonoassorbenti sala conferenze

As shown in the graph, on the basis of the acoustic absorption coefficients of the products – tested in a reverberation chamber according to the ISO 354 standard – it has been possible to determine the quantity of sound-absorbing panels needed to achieve the goal. Thanks to the installation of 38 Hanging Silente panels with size of 120x120x5 cm, the average reverberation time has decreased from 2,75 s to 1,15 s, in line with the optimal value prescribed by the standard.

In the design of a conference hall, we should therefore pay particular attention to the choice of finishing materials to ensure a low reverberation time, suitable for the intended use of the hall. Equally important is the distribution of the sound-absorbing material: in this case, Silente panels have been installed on the back and side walls. On the ceiling, however, they have been distributed in order to ease the proper sound propagation and, at the same time, to obtain an adequate level of speech intelligibility from every listening position in the room.