Brüel Acoustics

Studies and Research Projects

Brüel Acoustics, with some Universities and Research Centers, is working on important european projects and studies:

Studies:
2) Noise evaluation of light propeller-driven aircraft.
3) Noise from smaller Airport.
4) Time constants in the human ear and their consequences.
5) New form for acoustic instruments: SPHERES.
6) Quality Acoustics in Rooms: STI.
7) Noise Barriers.
8) Durst Measurements: a new test chamber.

Research projects:
1) A new method for Measuring Vibration Flow.
2) Microburst.
3) Acoustical Absorption:
4) Noise effect on human ear and Coclear Mechanics with A.I.R.S. a no profit Italian Association for Research on deafness.

Research Project on
Acoustical Absorption as Function of Angle of Incidence and Distributing of Material:

As already mentioned Brüel Acoustics think that reverberation time RT is not the best parameter for describing the acoustical quality of a room due to the large spreading in the measurement of RT.
Consequently, to determine the absorption as function of frequency, by using the ISO standardized methods, is a very doubtful business.
Brüel Acoustics prefer to evaluate absorbing material with a SWT which give a very precise value for perpendicular incidence.

Brüel Acoustics have already confirmed some theoretical results for or as function of the angle of incidence, see fig. 1.
We can therefore already now, as seen, convert results measured with a SWT to any angle of incidence or to diffuse field.
We have also some preliminary results for the increase in absorption when the absorbing material is divided.
It can be seen that the absorption per m2 increase when the material is set up in smaller areas. But these latter results will be further investigated in a future research project.

Brüel Acoustics have already used these preliminary results for developement of AcoustiCone 61 BA and AcoustiCassini 61 BB.

With these results in hand we have a cheap and fast method to develop and optimize absorbing material.
Some Results 1 (77 Kb)
Some Results 2 (100 Kb)

Acoustical Quality at the Opera Theatre of Roma (69 Kb)

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