The noise emissions of wind turbines lead to extensive problems for manufacturers as the approval process and the development site are influenced. Against this back­ ground the industry requires immediate action. Due to legal requirements and acceptance problems of wind tur­ bines in the population, acoustic emissions are a signifi­ cant issue for manufacturers. Over the last decade the average...

background and aim: speech understanding almost never occurs in silence. verbal communication often occurs in environments where multiple speakers are talking. in such environments, babbling noise masks speech comprehension. consonants, in comparison to vowels, are more sensitive to noise masking. consonants provide most acoustic information needed for comprehending the meaning of the word. sin...

The practical usefulness of long-range acoustic measurements of ocean acidity-linked sound absorption is analyzed. There are two applications: Determining spatially-averaged pH via absorption measurement and verifying absorption effects in an area of known pH. The method is a differential-attenuation technique, with the difference taken across frequency. Measurement performance versus mean freq...

The primary source of aircraft noise is the fan noise from the engines; natural approaches to reducing this noise involve acoustic shape optimization of the inlet and impedance optimization of the liner. This project will use optimal control to systematically determine the inlet shape and the linear material impedance factor that minimize the fan noise. A novel feature of this approach is that ...

Airborne sound insulation index of the noise barrier panel and the sound absorption coefficient of the barrier surface are the acoustic parameters that are usually determined in specialized laboratories, however they can be also determined in situ. Acoustic characteristics of a barrier include also the diffraction index difference determined from comparison of barriers with plain top edges and ...

We present an initial parametric investigation of fan flow deflectors for suppressing noise from supersonic turbofan engines. Realistic exhaust geometry and flow conditions for bypass ratio 2.7 were simulated in a subscale experiment. The study encompassed acoustic measurement and mean velocity surveys. The deflectors comprised internal vanes with both symmetric and cambered airfoil sections an...

Wind induced noise is one of the major concerns of outdoor acoustic signal acquisition. It affects many field measurement and audio recording scenarios. Filtering such noise is known to be difficult due to its broadband and time varying nature. In this paper, a new method to mitigate wind induced noise in microphone signals is developed. Instead of applying filtering techniques, wind induced no...