[ICA2019] Improving in-situ sound absorption measures using sparse multichannel blind deconvolution
Channel: Prof. Bruno Masiero
Date: 2020-08-12

The sound absorption of materials is traditionally measured in laboratory condition with one of two methods:  random incidence in a reverberant chamber (ISO 354) or normal incidence in an impedance tube (ISO10534). Nevertheless, there are some materials that cannot be measured in the lab, e.g., road surfaces, which are recommended to be measured in-situ with the use of a single microphone (ISO 13472). The latter method is based on time-windowing the measured impulse response to compare the incident and reflected wave components. Depending on the measurement setup, the size of the window may result in degraded measurement quality, specially at low frequencies. With the intention to alleviate this effect we evaluate three blind de-convolution approaches.  These methods blindly estimates the response of the sound source, resulting in a cleaner (possibly more sparse) measurement that can than be used to estimate sound absorption. We compare the results of the aforementioned methods with free-field and averaged equalization for measurement at a wall covered with PET-wool.  Even though the evaluated methods were able to “sharpen” the measured impulse responses, it showed no improvement in the calculation of the absorption coefficient.


Thank you Sérgio Aguirre (https://www.youtube.com/user/serginhodjk) for the recording.