Menu
We carry out acoustic design activities for traditional office buildings, schools, hospitals and housing, as well as for large entertainment venues such as cinemas, theatres, auditoriums and opera houses.
We take care of all aspects of projects, studying the acoustic quality of the spaces, sound insulation between adjacent areas and protection from noise and the vibrations generated by mechanical systems.
We work on all the planning and design phases, from the preliminary studies to the final design, working drawings and specifications and the construction stage. We monitor the work carried out by conducting specialised observations in indoor and outdoor environments, with a view to guaranteeing compliance with the acoustic objectives established.
We provide support to professionals and businesses, because maximising the acoustic quality of a project and its implementation means improving people’s lives.
The acoustic behaviour of a closed space can be described using statistical theory, founded on the hypothesis of a perfectly uniform acoustic field throughout the environment on account of the absolutely random distribution of the propagation directions of the sound waves it is derived from. It will therefore be described by the mean values of the characteristic magnitudes. This method, based on the Sabine equation, can be used to effectively describe the reverberation phenomenon and to conduct a “quantitative” analysis of the materials that can effectively be used to control it.
The acoustic behaviour of a closed space can be described using the geometric method, which simplifies the situation by representing the sound waves using rays, derived from a source, which can propagate through the environment, reflecting off surfaces according to the laws of geometric optics. This is the system used in the acoustic simulation software used for “qualitative” project assessments, which evaluate the position and efficacy of the materials proposed, provided that the larger dimensions of the room studied is much larger than the wavelengths involved. This approach has no sense for smaller rooms with smaller volumes, for which the statistical method approach is sufficient.
To aid the design of acoustic insulation in buildings, the evaluation of passive acoustic requirements (Prime Ministerial Decree of 5/12/1997 and and UNI 12354 standards) and the acoustic classification of buildings according to the UNI 11367 standard, a software modelling tool should be used to take account of all possible structure-borne noise, in addition to the manual calculations of the construction packages.
When sound waves collide with a surface, they generate sound reflection, sound diffusion and sound absorption phenomena, depending on the physical properties of the materials the surface is made of. The acoustic quality of a confined environment will therefore depend directly on how these phenomena are managed and on the choices that must be accompanied by a detailed predictive study using all the methods and technologies available in order to optimise project choices.
Quando le onde sonore impattano contro una superficie, si generano fenomeni di fonoriflessione, fonodiffusione e fonoassorbimento del suono a seconda delle proprietà fisiche intrinseche dei materiali che la costituiscono. La qualità acustica di un ambiente confinato, dunque, dipenderà direttamente dalla gestione di tali fenomeni e dalle scelte che dovranno essere accompagnate da uno studio previsionale dettagliato che utilizzi tutti i metodi e le tecnologie a disposizione al fine di ottimizzare le scelte progettuali.
When a system of sound waves meets an object that is unable to vibrate, the waves reflect with a norm common to all such phenomena, according to which the angle of incidence is equal to the angle of reflection. The intensity and quality of the reflection depends on the characteristics of the reflecting surface. In any case, the part of the energy that is not reflected is absorbed or refracted. To study the contribution made by sound reflecting panels, in order to optimise positioning in section and in plan, a study is carried out of the first reflections and the “sound illumination fields” produced by the sound reflections according to the acoustic theory of ray optics. The calculation of the contribution made by sound reflecting panels to listening quality, and therefore of the different routes travelled by direct sound and reflected sound, and of the range of frequencies of interest the pertinent reflections should be applied to, enable the identification of the positioning in plan and in section and the angulations, as well as the depth, density and thickness of the individual panels.
To optimise sound insulation, the construction packages that make up the vertical and horizontal partitions of a building, as well as the door and window frames, must be designed adequately. For this purpose, there are two physical principles that can boost the sound insulation performance of walls and floors: the “law of mass action”, suitable to assess the performance of monolithic walls, and the principle known as “mass-spring-mass, to be applied to counter-walls or light walls. Choices must be made based on the limits set by the regulations in force and the performance objectives established.
An EVAC system is “an electroacoustic system mainly designed to transmit information to protect people in one or more specified areas during an emergency […]. It is used for the swift, orderly mobilisation of the occupants of an area inside or outside, in an emergency situation”: this is the definition provided in the current CEI EN 50849 Standard “Sound alarm systems of emergency applications”, in force since February 2019. This system is mentioned in the Fire Prevention Code, in paragraph G.1.14 “Active protection”, meaning the antifire measures suitable to reduce the consequences of a fire, requiring either human intervention or the activation of an antifire system.
We design audio video systems for conference rooms, meeting rooms, public entertainment venues, cinemas, theaters and auditoriums according to the latest generation standards and technologies.
Compliance with passive acoustic requirements requires works not only to be designed effectively, but also to be carried out properly. To verify that the requirements established at the design stage have been achieved and that the regulatory limits set out in the Prime Ministerial Decree of 5/12/97 have been complied with, the passive acoustic requirements must be tested on-site. This testing must be conducted by an environmental acoustics technician, using measurements performed in accordance with the procedures indicated in the UNI EN ISO 140 standards, using the appropriate instruments (class 1 sound level metre, dodecahedral source, unidirectional speakers and tapping machine). Once the measurements have been taken, the technician calculates the assessment scores in accordance with UNI EN ISO 717-1/2 and drafts the test report indicating whether the passive acoustic requirements have been complied with.
The first environmental acoustic parameter to be measured was reverberation time, by Sabine, at the end of the 19th century, and this remains the most important descriptor in analysis and in the acoustic design of a confined space. Reverberation time is defined as the time interval between the moment the source of the acoustic signal has been turned off and the moment the energy density is reduced to one millionth of its original intensity. Reverberation time is measured by estimating the decay of the sound produced by the sound excitation, which may occur in three ways: interrupted noise, impulsive source and ‘Sweep-Sine’ exponential sinusoidal sweep. Interrupted noise consists of excitation of the environment using an omnidirectional source driven by a power amplifier that generates a broad-spectrum (from 50 Hz to 10 kHz) white noise, and when the source is interrupted, using a sound level meter, the decay time is measured. The advantage of the impulsive signal is that it can be generated easily by an explosion, which can be obtained, for example, by firing a gun; the impulsive signal is short and thus allows excitation to be distributed simultaneously across a broad frequency band.
The Speech Transmission Index (STI) is an indicator of mean speech intelligibility. STI scores range from 0 (completely unintelligible) to 1 (excellent intelligibility). The STI has been correlated to subjective intelligibility scales. The methods for measuring intelligibility are based on the determination of the modulation transfer function (MTF) in 7 octave bands, and must be carried out using specific instruments. STI measurement is one of the methods applied to test, for example, signalling and alarm systems.
Surveys conducted in living environments measure levels of both environmental and residual noise. Environmental noise level is the A-weighted equivalent continuous noise level, produced by all the sources of noise present in the environment under investigation; therefore, it is made up of residual noise plus the noise produced by the specific disturbing noise sources, with the exclusion of individually identifiable sound events of an exceptional nature, and is the level that is compared with the maximum exposure limits. Residual noise level is detected when the specific disturbing noise source is excluded from the measurement. It must be measured with methods identical to those used for measuring environmental noise.
Prime Ministerial Decree no. 215/99 established the maximum noise levels permissible in entertainment and public performance venues and in public establishments (excluding temporary and mobile activities) equipped with electrical sound transmission and amplification systems. The regulation establishes the maximum sound pressure limits to be complied with in order to limit exposure to noise. It is necessary to verify whether the system is equipped with features able to potentially exceed the limits.
If the system is able to exceed the limits, an acoustics technician will indicate the actions necessary to bring the system back within the limits established in the regulations. Once these actions have been implemented, the technician must test the system and issue a technical report to be attached to the Self Declaration made by the manager of the activity.
