Former Church of the Battuti

NEEDS

CURRENT SITUATION

The Rooms to be set up present different situations that require technological improvements in favor of more effective communication.

In various rooms, the difficulty in using the audio which does not give the desired feedback in terms of speech intelligibility was underlined, due to the type of loudspeakers used, their positioning, the type of microphones and the switchboard which are inadequate.

Furthermore, the acoustics of the restaurant rooms negatively affect the understanding of the word due to the reverberation present and therefore a difficulty has been detected in maintaining a pleasant conversation without effort.

DESIDERATA

In particolare, dal colloquio intercorso, è emersa la volontà di ottenere questa nuova situazione ideale:

La sala polivalente dovrà poter essere utilizzata con maggiore facilità e quindi sia come sala conferenze che meeting per poter ospitare lo svolgimento di eventi o meeting o feste o cene. Sarebbe quindi gradita la presenza di un impianto audio completamente intelligibile, fedele ed utilizzabile da tutti e idoneo per lo svolgimento di eventi. L’audio dovrà inoltre essere amplificato all’esterno, con la possibilità di suddividere le varie zone in base alle esigenze e ai diversi tipi di eventi. La sala dovrà essere inoltre corretta acusticamente per consentire all’impianto di funzionare in modo ancora più agevole ed ottimale.

Le sale ristoranti necessiteranno anch’esse di essere corrette acusticamente al fine di permettere una conversazione piacevole dei commensali.

BENEFITS

You will have Environments designed and organized to work at the maximum technological possibilities.

Anyone who uses your Sale will find a wonderful coherence between the advanced technology and the contents conveyed.

You will have continuously guaranteed assistance to handle any emergency with elegance and competence.

Sound and Images will become perfect allies to bring every word and every conscious and unconscious concept to the heart of the listener.

You will have the certainty of using every single instrumentation with the maximum technological response obtainable from your working environments.

Acoustic and audio comfort will be total: both on the part of those who will provide the interventions, and on the part of those who will be able to enjoy the best possible technological response.

It will be a pleasure to talk, listen and see everything around you.

The natural transmission of both sound and images will give you the sensation of being in the right place and having (and also giving) the best.

PREMISE

“Every environment requires a made-to-measure suit that corresponds to the values to be transmitted. Only in this way will the message be coherent.”

In any closed environment, the sound that is heard is the result of a combination of sound waves that reach the listener directly and sound waves that arrive reflected, or that propagate from the source until they affect the various rigid surfaces that delimit the environment from where they are reflected, often several times, before reaching the listener. The quantity that describes this acoustic characteristic of closed environments, often erroneously referred to as “echo”, is the reverberation time (TR), i.e. the time during which a certain amount of sound energy continues to persist inside a closed environment after the beep has stopped. The longer this time is, the greater the contribution of the reflected sound compared to the direct one. For example, if a sound source ceases to radiate in a room, the sound level decreases the more slowly the lower the sound absorption of the walls.

Reverberation has negative aspects, such as the risk of masking speech syllables or musical phrasing, and positive aspects, such as reinforcing the intensity of the source; however, the latter aspect can become a negative aspect in potentially noisy environments such as canteens, corridors, and gyms, as the internal reverberation contributes decisively to increasing the sound intensity, leading to excessively noisy environments. The elements present inside a closed environment (walls, furnishings, people, etc.) condition the acoustic propagation, since they absorb the sound energy that affects them to varying degrees. These phenomena can alter and deteriorate the quality of the sound perceived by the receiver, causing, for example, the degradation of verbal communication or listening to music.

To define the acoustic quality of a room, the quantity called “reverberation time” has been identified, which indicates the time, in seconds, necessary for the sound level to decrease by a certain amount in a point of a closed room compared to that which occurs when a sound source is interrupted. As a rule, the reverberation time T60 is used, i.e. the time interval in which the sound energy decreases by 60 dB after the source is switched off. In an environment having spatial dimensions fairly close to each other, the value of T60 can be calculated according to Sabine’s formula.

T=0.161V/A (s)

where V is the room volume in m3 and A is the total absorption equivalent area in m2. The value of A is obtained with the following relationship:

A = Σ αi Si (m2)

where αi is the i-th absorption coefficient and Si is the i-th surface area of the elements present in the environment. Acoustic absorption represents the ability of a material to convert the energy of an incident sound wave into a form of energy other than acoustic energy (usually into heat).

The determination of the reverberation time of an environment is therefore fundamental in order to be able to judge its acoustic characteristics and decide whether to intervene on the structures that delimit it, increasing its sound absorption capacity. It is necessary to intervene if the value of the reverberation time T60 is not at least close to the optimal value, obtained on the basis of table values in the literature or from sector standards.

By way of example, the diagram below shows the optimal values of the reverberation times as a function of the volume of the room and its intended use, taken from the literature on the subject.

However, the phenomenon of reverberation has both positive and negative aspects. In fact, if a certain value of the reverberation time helps to reinforce the direct sound and therefore to improve listening, on the other hand, an excessive value of the sound tail compromises its quality, making the sound muddy. Obtaining optimal reverberation time values represents the right compromise between achieving a sufficient sound level for effortless hearing, in all points of the room, and reducing the disturbance caused by an excess of reverberation. In general, for rooms intended for listening to speech, the ideal values of T60 are shorter than those for rooms intended for listening to music, as the diffusion of music requires a greater emphasis on the spatial effect. Furthermore, it is necessary to consider that an increase in the volume of the environment corresponds to an increase in the optimal reverberation time. In this case, it is necessary to slightly compromise listening in favor of a higher sound level value.

Regulatory framework

With regard to the passive acoustic requirements and the acoustic quality of the environments, it is useful at this point to underline that in July 2010 the UNI 1136700_2010 standard was published which establishes the new evaluation criteria of the acoustic requirements and the acoustic classification of the buildings, going to correct the gaps in the law in force (DPCM 5/12/97); this legislation has not yet been implemented by the legislator, therefore it is currently a voluntary acoustic quality standard.

It should be emphasized that this technical standard in Appendix C also takes into consideration the internal acoustic quality of the rooms on a general level, indicating some acoustic quality parameters including the reverberation time:

See below an extract from the aforementioned appendix C, which indicates a method for determining the optimal reverberation time for different types of environments, i.e. environments used for speech or used for sporting activities.

ACOUSTIC EVALUATIONS

The venue under analysis consists of a multi-purpose hall with a rectangular plan with a portion of the wall on the entrance side and a raised area for the stage.
Being a former church, the venue consists of a high barrel vault, with 4 nails on the long walls and an apse area behind the stage.

The room is heated by 8 electric radiant panels suspended from 4 metal rods placed at the height of the vault frame.

It should be noted that the project and the calculation of the volumes and internal surfaces was made on the basis of the measurements received, as well as the photographic images.

First of all, using the formula proposed by UNI 1136700_2010, we are going to calculate the optimal reverberation time for the rooms in relation to their internal volume, which has been calculated to be:

Multi-purpose hall Internal volume = approximately 663 m3

Since these environments are not for sports, but essentially environments dedicated to listening to the word, it is believed that the Tott calculated using formulas C.1 proposed by UNI 1136700 should be indicated as the optimal reverberation time

So the average optimal reverberation time between 500 and 1000 Hz for the room under analysis is:

Tott C.1 Multipurpose room = 1.06 s (rooms dedicated to listening to the word) Tmax Multipurpose room = 1.27 s (rooms dedicated to listening to the word)

The plan of the environment under analysis is shown below and it is once again highlighted that, in the absence of a survey, the same was done on the basis of the few measurements and images received. Therefore the position and size of the radiating elements suspended from the metal tie rods has been deduced from the images and therefore must be proven on site.

ACOUSTIC ANALYSIS

Based on the internal surfaces of the hall, taken from the architectural project as well as from the images received, the estimated internal acoustic analysis of the current hall is reported below.
It should be emphasized that an acoustic absorption quota has also been introduced due to the furnishings present and to a minimum of people inside the environment.

Room volume 1620.00 m3

SOLUTION

The solution, already mentioned during the inspection and considering the architectural form of the environment that you want to keep as unchanged and completely visible as possible, is the addition of melamine foam cylinders with a diameter of 24 cm and a height of 120 cm, which therefore they develop about 1 m2 of sound-absorbing surface.

Below is the calculation of the living room in the same configuration calculated previously with the addition of 86 melamine cylinders which will be suspended by means of nylon cables at various heights and distributed over the entire surface of the room for a total of approximately 86 square meters sound absorbing.

Room volume 1620.00 m3

With the insertion of sound-absorbing material, the internal reverberation time is considerably reduced, even if not such as to reach the optimal reverberation time, but in any case such as to reduce the reverberation time by about 2 seconds with obvious benefits for the acoustics of the hall and with a notable improvement in terms of speech intelligibility, even in the absence of the sound diffusion system.

Below is a hypothetical arrangement of the cylinders placed on a 0.95×1 m grid where space has been left for the suspended heating elements:

SELECTED MATERIAL

TOTO MELA©

Of great aesthetic prestige, these cylinders belong to the family of expanded resin panels and are dedicated to correcting acoustic problems in open space rooms with large volumes and are particularly suitable for installation in high-rise rooms. The Cylindrical sound-absorbing elements are made in a single monolithic block of acoustic resin, by means of a double axis cutting machine which allows to obtain each required section. The particular method of installation suspended from the ceiling allows the elements to be placed in an intermediate position with respect to the free volumes of the rooms, interposing themselves with the trajectories of reflection of the sound waves between the various surfaces and producing a cut in the “sound tail” of the sounds, thus generating considerable benefits on the Reverberation Time. The panels in the Cilindri series have high sound absorption properties due to porosity, due to the physical alveolar structure of the expanded resin, with excellent performance even at low frequencies thanks to the high thickness of the material that makes up the elements.