Articles and Case Studies from Norsonic AS

Case Study - Siemens Industrial Turbomachinery AB

Problem Two large gas turbines (approximately 25m x 12m x 10m) were installed in an industrial area nearby an office building. The gas turbines generate a tonal noise component at around 2700Hz caused by the inlet channel blades pass frequency. ...

Jan. 12, 2017

Case study - Use of the Nor848A acoustic camera on wind turbines

The acoustic camera system Nor848 is a powerful tool to investigate noise sources. In realtime you listen to a beamformed audio signal so that you can hear individual sources one by one. Immediately you can identify the strongest over all noise ...

Jan. 12, 2017

Acoustic camera and beampattern

Abstract—The wavenumber-frequency response of an array describes the response to an arbitrary plane wave both in time and space. When the input consists of a single monochromatic plane wave, the response of the array is referred to as the ...

Jan. 12, 2017 Jørgen Grythe

Array gain and reduction of self-noise

Abstract—Because an array is composed of many sensors, each making an independent measurement of the wavefield, intelligent combination of the sensor signals should lead to an overall increase in the signal-to-noise ratio. What we are trying ...

Jan. 12, 2017 Jørgen Grythe

Beamforming algorithms - beamformers

Abstract—Beamforming is the name given to a wide variety of array processing algorithms that focus or steer the array in a particular direction. Beamforming techniques are used to enhance directivity, and to aim the focus of the array without ...

Jan. 12, 2017 Jørgen Grythe

Sparse arrays and array health check tool

Abstract—Removing one or several microphones from an array creates a so called sparse array compared to the original design. The array geometry is then an altered version of the intended design, with a different beampattern than the full ...

Jan. 12, 2017 Jørgen Grythe

Cloud computing for noise monitoring

ABSTRACT Cloud computing is the use of computing resources that are delivered as a service over the Internet. This means that software, hardware and network resources are centrally managed. The ubiquitous availability of high-capacity networks and ...

Jan. 9, 2017 Thorvald Wetlesen

Case study - Filming sound leakages in highly reflective office environment

Problem A newly built office complex is designed with glass facades between the offices and the hallway. The glass facades include a glass door. Although the glass structures themselves have a sufficient sound reduction value, the sound insulation ...

Apr. 1, 2016

Case study - Filming breakout noise from café and concert venue

Problem A combined bar, bistro and concert venue in the city center has been renovated with a great emphasis on acoustic noise dampening. Nevertheless, the venue is still getting complaints from neighbours close by due to breakout noise from the ...

Mar. 1, 2016

Case study - Measuring impact of traffic noise in apartment living room

Problem An apartment on the ground floor of a two story house in the city lies close to a busy road. The living room in the apartment is facing the road, and the inhabitants are bothered by traffic noise, especially in the morning and the ...

Feb. 1, 2016

Case study - Wall leakage testing in the lab with acoustic camera

Problem Facade insulation testing is usually performed by using a loudspeaker in the sending room, and record the sound pressure level (SPL) with microphones in both the sending and receiving room. The difference in SPL adjusted for the size of the ...

Nov. 1, 2015

Case study - Using acoustic camera inside caravan car to find squeak and rattle noise

Problem When driving a caravan car, the driver could hear annoying noises from behind the driver’s cab in the living compartment. Even though the noises could be heard clearly, it was very difficult to discover the exact location and cause of ...

Oct. 1, 2015

Case study - Filming low-frequency structure born noise with acoustic camera

Problem An apartment complex consists of five floors, with several apartments over four floors, and an attic on the top floor. In the attic an air circulation system is installed to provide circulation in the bathroms of all the apartments in the ...

Sep. 1, 2015

Case study - Pinpointing low level sanitary noise in apartment building

Problem A newly built apartment building consists of several floors with multiple apartments on each floor. One of the ground floor apartments is disturbed by sanitary noise from the apartment above, which is heard whenever the toilets in the top ...

Apr. 1, 2015

Case study - Finding acoustical weak points in room dividing modular walls

Problem A conference hotel is using modular walls to divide large halls into several smaller conference rooms. The rooms are divided by modular walls that provide several different opportunities for subdivision and multipurpose use of the large ...

Nov. 1, 2014

Case study - Identifying low-frequency tonal noise in windy and noisy conditions

Problem A large LNG gas facility (approximately 300m x 150m) producing 300 000 tons of LNG annually is situated in a terminal area with the nearest populated area at a distance of around 1 km. Within the gas production facility, a low-frequency ...

Sep. 1, 2014

Case study - Nor848A Acoustic Camera Metro station in Taipei, Taiwan

After the construction of the elevated sky train, too high noise levels were appearing under the line and local communities were complaining. Therefore acoustic absorbing panels were mounted under the metro line at critical sites in order to reduce ...

May 1, 2013

Norsonic AS Articles