Environmental Acoustics Articles

  • 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 source in a multisource environment, and you can do the same analysis for single frequencies, 1/3 or 1/1 octave bands or any given frequency range. This ...


    By Norsonic AS

  • On the right track

    High-speed train manufacturer, CAF, rely on world-class beamforming technology to reduce the noise generated by their trains – helping to make high-speed trains a more viable option for travellers and operators alike. Because of its relatively low levels of CO2 emissions, train travel is considered one of the ...

  • Optimus and Invictus are the Classic Combination - Case Study

    Imagine a perfect summer’s evening with a 40-strong classical orchestra playing to an appreciative audience in a leafy green park. So far, so very English. Add in the fact the Park is in the heart of Lancaster city surrounded by thousands of homes and the orchestra is playing sets of the Hacienda’s classic 90s house music hits and you can understand the headache facing Acoustic ...


    By Cirrus Research plc

  • 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 between office and hallway was measured at 19 dB, which was far below the sound insulation criteria for offices given in the regulations. It ...


    By Norsonic AS

  • Cam correlation analysis using Acoustic discharge measurement

    The low head hydro power plant in Wettingen, Switzerland, is in operation since 1933 and no effective cam optimization has been carried out up to now. The goal of the measuring campaign was to provide data enabling an economic study for a retrofit and upgrade project of the plant and the measurement of the efficiency improvement of turbines after refurbishment. The contribution discusses cam ...


    By HydroVision GmbH

  • Discharge Measurement in a Short Intake with a Converging Section – a Case Study

    In the context of a planned retrofit and upgrade of the hydropower plant Wettingen, operated by the Elektrizitätswerke Zürich, three intakes were equipped with acoustic transit time flow measuring devices. Since the flow meters are installed in a converging section, downstream of a pier, it became necessary to perform numerical flow simulations in order to weight the acoustic path ...


    By HydroVision GmbH

  • 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 dividing wall element will then give an estimate of the sound reduction quality of that element. However these measurements will not say ...


    By Norsonic AS

  • Sensitivity of response of LISST-ABS and OBS to size distribution changes

    This Note shows how the calibration of the LISST-ABS acoustic backscatter sensor and of optical backscatter sensor (OBS) changes when water contains a broad distribution of particle sizes, and why LISST-ABS is inherently superior. Particle size distributions in water are usually not very narrow, i.e. particles of more than a single size exist in suspension. It is common practice to consider ...


    By Sequoia Scientific, Inc.

  • 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 the various annoying sounds due to overwhelming background noise. When the car was standing still with the engine running, no extra ...


    By Norsonic AS

  • Acoustically induced vibration: A review of industry best practice

    WKC Partner and Noise and Vibration practice leader, Richard Palmer, has recently had an article published in the Institute of Acoustics (IOA) Journal titled ‘Acoustically Induced Vibration: A Review of Industry Best Practice’. This technical paper, which provides the reader with a better understanding of the AIV phenomenon, was published in the IOA Journal in September 2015.  ...


    By WKC Group

  • Port of London Authority Tidal Monitoring System - POLATIDE 5: Detailed - Case Study

    Introduction: Valeport and OceanWise have designed and delivered a complete tidal monitoring system, including tide gauges, telemetry equipment, servers, databases, system control, data management and display software, to the Port of London Authority. The system was installed in October 2013 and rigorous testing completed in February 2014.  Background: ...


    By Valeport Ltd

  • How Often You Should Calibrate A Sound Level Meter

    Do you calibrate a sound level meter frequently? Most sound level meter users know they must calibrate their sound level meters but a questions I frequently get asked if “how often?” Here’s my best practice advice so you can calibrate with confidence. What Do We Mean by Sound Level Meter ...


    By Cirrus Research plc

  • Short-term noise monitoring with Delta Acoustics case study

    Noise monitoring does not require a large amount of expertise or investment in expensive equipment. DELTA learned how measurement projects with high technology demands could easily be solved with a Noise Sentinel On Demand subscription. Challenge Demands for quick calculation validations on noise measurements that had to comply with strict ISO regulations ...

  • Development of a long duration, free swimming, inline acoustic leak detection inspection tool

    Abstract Acoustic leak detection inspection tools have become a common technique to identify minute pipeline leakage before the leak and the defect producing it can become a larger problem or even a rupture level event. While these inspection tools only identify small ...


    By Pure Technologies

  • Numbers don’t Lie, PCCP performance and deterioration based on a statistical review of a decade of condition assessment data

    Abstract Since the late 1990s there have been numerous inspection and monitoring projects focused on identifying and quantifying wire break damage in PCCP water and wastewater pressure mains. The pressing need to identify and manage deterioration of PCCP has resulted in the rapid development of a small but highly focused niche industry of condition assessment of PCCP mains. During this ...


    By Pure Technologies

  • Enclosure for small laboratory equipment case study

    Process Details Large cryogenic mill designed for cryogenic grinding and pulverising tough and temperature sensitive samples immersed in liquid nitrogen. Supply Stainless steel desktop acoustic enclosure 760mm wide x 720mm deep x 710mm high Product selection Enclosure needed to be lockable, able to collect ...


    By Wakefield Acoustics Ltd

  • A study of the coincidence effect and critical frequency of a dash panel using the hybrid FEA–SEA and experimental methods

    This paper provides a new method to determine critical frequencies of any engineering structures by identification of peak frequencies of their internal damping loss factor curves. The novelty embodies the following aspects: first, the indirect method was applied to measure the critical frequencies of large complex thin–walled panels; second, the hybrid FEA–SEA was applied to analyse the sound ...


    By Inderscience Publishers

  • 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 area spaces. When measuring the sound insulation between adjacent rooms through the modular walls, the resulting value was found to be too ...


    By Norsonic AS

  • Compact disk parts precision machining --- The Hermos CNC Grinder

    MGK20 CNC grinder is an internal grinder which is specially manufactured to produce micro and mini disk parts and other small parts. Shenyang Hermos Machine Tool Co. is manufacturing MGK20 of Alzheimer CNC high-precision grinder, especially for micro and small parts machining and design. MGK20 CNC internal grinder is suitable for batch processing of high-precision parts, machining precision ...

  • A novel acoustic imaging tool for monitoring the state of rapid sand filters

    A new technology based on acoustic waves is developed to monitor the state of sand filters used in drinking water treatment. Changes in the sand filter, due to the removal of suspended particles from the water and their accumulation in the pores, result in an increase of the bulk density and acoustic speed of the granular material. Consequently, the reflected acoustic response changes as the ...


    By IWA Publishing

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