Amelia Trematerra

Acoustic Measurements and Correction of a Council Room

This paper presents the acoustic correction of a Council Room, with an original reverberation time of 1.0 kHz higher than 3.0 seconds and marble floors walls and ceiling in plaster smooth. The work was conducted in four phases: the first was the measurement of acoustic characteristics with the empty hall; the second phase was the identification of the soundproof material for the acoustic correction and the measurement of the absorption coefficients with the tube of “Kundt”; the third phase was the implementation of a numerical model with the software “Odeon” to choose the position of absorbent material and of the plaster surface to be coated; the latest phase, after the installation of soundproof panels, was the acoustic measurement to verify if the results of the acoustic measurements are equal to those one of the numerical model.

The Large Theatre of Pompeii: Acoustic Evolution

This paper reports the acoustic evolution of the “Large Theatre” of Pompeii: during the Greek-Hellenistic and Roman period, and through to the present time. Initially the style of the theatre was Greek-Hellenistic with an elongated U shape and a cavea built into the top of a hill. During the Roman period the theatre shape was changed with a larger scene and a summa cavea added to accommodate about 5.000 spectators. After being recovered from under the Vesuvius lava it was partially reconstructed. Most recently the original grass-covered cavea has been paved with bricks and today the theatre provides a venue for a variety of types of performance. Its acoustic characteristics have been analysed using a virtual model for the Greek- Hellenistic and Roman period, and then, for the later configurations, when the cavea was grass-covered and then paved with bricks, with acoustic measurements.

The acoustics of the catacombs of San Callisto in Rome

The present study shows the acoustic properties of the catacombs of “St. Callisto” in Rome. Same acoustic measurements were made to understand which type of religious functions could have been celebrated in them, in particular, if they were spoken or sung. The catacombs were places of burial, but they were also places of reunions and visits to the graves of the martyrs. The catacombs are places for burial, diffused in the different religions of the different zones of Europe and Mediterranean Asia, not only Christian, even if they reached the maximum diffusion with the Christianity, the presence of the catacombs in these places it is due to the fact that the subsoil is easily excavatable. The catacombs were generally built through the realization of burrows, with corridors that connected all the “cubicles,” rooms with a regular plant in which the burial happened. The acoustic measurements were carried out with an explosion of a balloon toy, with a microphone connected to a computer were measured the impuls...

Wind turbines acoustic measurements

The importance of wind turbines has increased over the last few years throughout the European Community. The European energy policy guidelines state that for the year 2020 20% of all energy must be produced by alternative energy sources. Wind turbines are an important type of energy production without petrol. A wind speed in a range from 2.5 m/s to 25.0 m/s is needed. One of the obstacles to the widespread diffusion of wind turbine is noise generation. This work presents some noise measurements of wind turbines in the South of Italy, and discusses the noise problems for the people living near wind farms.

Evaluation of noise when a disturbing sound source cannot be off

This article shows the results of a method of acoustic measurements performed when a disturbing sound source cannot be turned off. This case happens when it is not possible accessing to disturbing sound source that we want to characterize, or when it cannot be switched off for reasons linked to production cycle. It is possible to carry out acoustic measurement of residual noise (noise present when disturbing source is off) with the technique of acoustically similar place. The residual noise in a certain area is a result of noise level emitted from various sound sources operating with a certain typicality in a considered area. This noise is going to be combined with noise of disturbing sound source, in place where complaints show up. If it is not possible to control disturbing sound source, residual noise surveys may be carried out in a similar place, or in a place where an environmental noise is equal and the influence of disturbing sound source is negligible.

Sound absorption with green materials

Green materials are a valid alternative to traditional materials that are by-products of processing oil. At the end of their useful life, green materials can be disposed of without polluting the environment. They are now being used in the construction and automotive industries. While, studies are currently being carried out in the aviation sector on the use of green materials for non-structural components of airplanes. Green materials can be used to improve the acoustic comfort inside buildings as well as mitigate reverberation, echoes effects and reduce the transmission of noise between rooms. In this paper, the acoustic measurements of the properties of green materials are reported. The absorption coefficient of samples of the materials were measured in the frequency range from 200 Hz to 2,000 Hz with an impedance tube, with the flow resistance being measured.

Use of cork as absorbent material

Cork is a green and sustainable material. At the end of its useful life, it can be disposed of into the environment without causing any damage. It can be used to improve the acoustics inside environments, as a system for the reduction of reverberation time. Sound absorption systems consist of cork panels mounted at a distance onto a rigid wall. The thickness of the cork panels considered are 1.5 mm and 2.5 mm. While the distances considered from the rigid wall are 3 cm, 5 cm, 10 cm and 15 cm. The absorption coefficient of the samples was measured in the frequency range from 100 Hz to 2,000 Hz with an impedance tube (tube of Kundt). Furthermore, the problems relating to the realization of sound-absorption systems composed of cork panels are also discussed.Cork is a green and sustainable material. At the end of its useful life, it can be disposed of into the environment without causing any damage. It can be used to improve the acoustics inside environments, as a system for the reduction of reverberation time. Sound absorption systems consist of cork panels mounted at a distance onto a rigid wall. The thickness of the cork panels considered are 1.5 mm and 2.5 mm. While the distances considered from the rigid wall are 3 cm, 5 cm, 10 cm and 15 cm. The absorption coefficient of the samples was measured in the frequency range from 100 Hz to 2,000 Hz with an impedance tube (tube of Kundt). Furthermore, the problems relating to the realization of sound-absorption systems composed of cork panels are also discussed.

Acoustic Properties of Cork Sheets

Green materials can be considered as a valid alternative to traditional synthetic materials. The cork is a green material, in fact it is a sustainable material. Cork can be used to improve the acoustics inside buildings. The systems used consist of cork sheets mounted at a distance onto a rigid wall, with the thickness of the sheet being 1.5 mm. The distances from the rigid wall considered are equal to 5 cm, 10 cm and 15 cm. The absorption coefficient of the sample was measured in the frequency range from 100 Hz to 2000 Hz with an impedance tube.

Green Materials for Sound Absorption

Green materials are becoming a valid alternative to traditional synthetic materials. The green materials can be used in different fields of the building constructions. The green materials are sustainable, infact the at the end of its useful life they can be dispersed into the environment without damaging it. So the green material can be used in improving the acoustic comfort inside environment, as well as to mitigate noise pollution. In this paper are reported the acoustic measurements of the properties of green materials. The absorption coefficient of samples of the materials, were measured in the frequency range from 200 Hz to 2,000 Hz with an impedance tube (tube of ”Kundt”); the flow resistance was also measured. Furthermore the problems about the realization of sound-absorbing panels composed of green materials, used for the acoustic correction of classroom, were discussed.

The acoustics of the catacombs of Vigna Cassia in Syracuse

The aim of this study is the evaluation of acoustic characteristics of the burial place in particular the Vigna Cassia’s catacombs in Syracuse. In late antiquity (III - VI cent. A.D.), the catacombs were the burial places of the Christian communities, but they were also places for prayer and sacred functions, celebrated especially for the presence of the tombs of the martyrs. The study of the acoustics of the catacombs was performed with the technique of the impulse response, some firecrackers were detonated in different areas of the catacombs and the answers were realized in function of the monaural parameters STI, T30, EDT, C80 and D50. The acoustic study was performed to define whether in such places, with complex geometries and interconnected tunnels, there are favorable conditions for speech understanding and for meditation and prayer.