Installation

1. Coupled semi-anechoic and reverberant chambers

Measurements:

  • Diffuse field sound absorption coefficient according to ASTM C423-09a or ISO 354
  • Sound transmission loss of partitions according to standard ISO 15186-1 or ASTM E2249 − 02
  • Sound power level of noise sources according to standard ISO 3745, ISO 9614-1 and ISO 9614-2
  • Localization and noise maping of acoustics sources using acoustical imaging techniques (sound intensity ans beamforming)
  • Acoustic attenuation (IL) provided by hearing protector devices (HPDs) using test subjects or acoustic test fixture (ATF)
  • Occlusion effect provided by HPDs using test subjects or realisitic artificial ears developed during our research projects

2. Audiometric booths (x2)


Measurements:

Measurement of the acoustic attenuation provided by hearing protector devices using the audiometric thresholds techniques:

3. Characterization of acoustical materials


Measurements:

  • Sound absorption coefficient and sound transmission loss of acoustical materials submitted to normal incidence plane waves (impedance tube techniques) according to standards  ISO 10534-2, ASTM E1050 and ASTM E2611. Three different impedance tubes allow to cover the frequency range [50Hz-6000Hz].
  • Airflow resistivity of acoustical materials  according to standard ISO-9053
  • Open porosity : isothermal pressure/masse method for which the weight of the sample is measured when it is submitted to various static pressure and various gazes. This method is weel adapted for sound absorbing materials (low density and high open porosity).
  • Tortuosity using ultrasound techniques (transmission et en reflection methods)
  • Mechanical properties (Young’s modulus, Poisson coefficient, loss factor) at low frequencies using quasistatic technique according to standard ISO-18437-5
  • Insertion loss of hearing protectors devices submitted to low or high sound pressure levels (<155 dB): this method is based on the use of an impedance tube and it is currently under development.

4. Noise source localization

Measurements:

The methods developed and performed at ICAR allow to localize both stationary and non-stationary noise sources, broadband (white noise, road traffic) or tonal (pure tone, whistling) sources situated either in free field or in a reverberant acoustic field (multiple reflections on the walls). The main used methods are:

  • Beamforming in the frequency domain
  • Beamforming in the time domain
  • Intensimetry
  • 2D or 3D acoustic maps

Equipment:

  • Pulse data acquisition system with 42 inputs (Brüel&Kjaer)
  • Intensimetry probe I-Track coupled to video camera and a maping software
  • Spherical antennas optimized during our research projects