reference sound source Articles

  • Noise, sound, decibels, hearing

    A decibel–a measure of sound. Like all short answers, this one leaves out a lot. When we hear a sound, its because our brain has received a nerve impulse from the nerve cells in the Inner Ear, which consist of a bone, called the Cochlea because it resembles a snail shell. These cells have long “hairs” that project into fluid inside the cochlea. There is a hole in the cochlea ...

  • Research & development of sound quality in lifts

    The Consortium Orona S. Coop. (manufacturer of lifts), Mondragon Goi Eskola Politeknikoa (MGEP) S. Coop. (Engineering Faculty of Mondragon University) and Ikerlan S. Coop. (Research Centre) have formed a consortium and established a stable working group of engineers to investigate the Sound Quality in Orona’s lifts. MGEP, Ikerlan and Orona MGEP, the ...

  • Sound Level Meter Apps – How Accurate Are They?

    There has been a growing awareness of the availability and application of sound level meter apps providing noise measurement functions. Some of these sound level meter apps have been designed to meet, when used with a suitable external microphone, compliance with the relevant instrumentation standards. The vast majority of these are available as free downloads from the Google Play Store or the ...


    By Cirrus Research plc

  • The Basics of Sound Theory and Testing Principles: A Brief Guide for Environmental Professionals

    As awareness of environmental noise pollution grows, environmental professionals not specifically trained or experienced in the field of acoustics or noise control are being increasingly called upon to assess, predict,and/or quantify sound emissions from a variety of industrial sources. This article provides an overview of basic acoustical fundamentals, including the frequency ranges of primary ...

  • 50th anniversary of world`s first sound level meter

    Sound Level Meter Celebrates 50th Anniversary 2010 is the year we celebrate the 50th anniversary of Type 2203, the mother of all sound level meters. It was the world’s first precision hand-held and transitorised sound level meter. Produced for 21 years, it sold a record number of 17300 units. With its upgrades Type 2204 (Impulse time constant) and 2209 (peak detector), it accounted for a ...

  • Suzuki Wind Tunnel used for full-vehicle noise source identification case study

    The Suzuki name can be seen on a full range of motorcycles, automobiles, outboard motors, and related products and is recognised throughout the world for quality products offering both reliability and originality. And Suzuki is always creating advanced ‘value-packed products’ for their customers. So, in 2006, as one of their investments, Suzuki’s R&D division built a new ...

  • What is reverberation time and how it is calculated?

    What is the reverberation time of a room? Reverberation time is the time required for the sound to “fade away” or decay in a closed space. Sound in a room will repeatedly bounce off surfaces such as the floor, walls, ceiling, windows or tables. When these reflections mix, a phenomeon known as reverberation is created. Reverberation reduces when the reflections hit ...


    By Cirrus Research plc

  • INTA – exterior noise certification of Airbus A330 MRTT

    INTA is a Public Research Body specialising in aeronautic and space research and technological development. It owns a multitude of Brüel & Kjær products including a 30-channel PULSE system and a 6-channel LAN-XI system which are used daily. One of the latest and most important jobs performed by INTA is the Noise Certification of Airbus Military’s A330 MRTT which it achieved ...

  • Seeking Clarity in Noise

    Environmental noise regulation can be frustrating. The noise limits, applicable measurement metrics, assessment methods and level of enforcement vary a lot by region and jurisdiction and rarely do they all align. Historically, noise emitters and sensitive receivers could afford to use distance to separate themselves. Consequently, environmental noise laws were first developed in regions with high ...


    By Innova Global Limited.

  • Environmental Noise

    Introduction The ability to hear sounds is a sensory function vital for human survival and communication. However, not all sounds are wanted. 'Unwanted sounds', for which the term 'noise' is normally used, often have their origin in human activities (mainly transport, industry and households). This article addresses environmental noise ­ also referred to in the scientific literature as ...

  • Eionet connects Sharing environmental information in Europe

    The European environment information and observation network (Eionet) aims to provide timely and quality-assured data, information and expertise for assessing both the state of the environment in Europe and the pressures and driving forces acting upon it. This enables policymakers to decide on appropriate measures for protecting the environment at national and European level and to monitor the ...

  • Urban legends—Compliance pitfalls

    Maintaining update knowledge of OSHA requirements and keeping company safety policies current is a daunting task. There are many sources to turn to in order to obtain information about OSHA standards. There is the OSHA web site, seminars, consultants, professional organizations, colleagues, and countless other sources. As if the regulatory jungle isn’t difficult enough to navigate, the accuracy ...

  • Overview of Major Changes in EPA Draft Guidance for Vapor Intrusion

    The following provides a brief summary of the Draft Guidance for Evaluating the Vapor Intrusion to Indoor Air Pathway From Groundwater and Soils (Subsurface Vapor Intrusion Guidance). November 2002, EPA530-F-02-052. Major Points: This draft guidance supersedes the draft RCRA EI Supplemental Guidance for Evaluating the Vapor Intrusion to Indoor Air Pathway (Dec. 2001). It does not supersede ...

  • Monitoring - Pollution Prevention Guidelines

    Introduction Pollution Prevention Guidelines to provide technical advice and guidance to staff and consultants involved in pollution-related projects. The guidelines represent state-of-the-art thinking on how to reduce pollution emissions from the production process. In many cases, the guidelines provide numerical targets for reducing pollution, as well as maximum ...


    By The World Bank

  • ‘Kyoto cost’ of various production and recycling processes

    ‘Kyoto cost' of various production and recycling processes: An interesting take on the the total CO2 emissions released during the lifetime of various containers used in the manufacturing and delivery of bottled water and other fluid products typically consumed in North America ...


    By Baum Publications Ltd.

  • Noise at Work: Frequently asked questions

    Controlling Noise at Work: Frequently asked questions Pulsar Instruments are the experts when it comes to noise at work measurement. The company was formed 45 years ago and, over the years, the team has answered numerous phone calls or met new and existing customers at Trade shows, professional meetings or in their place of work to answer their queries. Very ...


    By Pulsar Instruments plc

  • North American Experience with Centrate Treatment Technologies for Amonia and Nitrogen Removal

    ABSTRACTThe discharge of ammonia and nitrogen to receiving bodies of water is becoming more strictly regulated at municipal wastewater treatment plants throughout North America. The dewatering of anaerobically digested biosolids creates a reject water stream (often referred to as centrate or dewatering filtrate) that can contribute to an additional 15 to 20 percent of the ammonia load to a ...

  • I Say Duplex, You Say Tandem, Let’s Call The Whole Thing Pumped!

    If you believe everything you read on the internet (even after Abraham Lincoln told you not to), you will get confused pretty quickly. Because the internet itself is often fairly confused, and thus confusing. And you really don’t need me to tell you; you already know. (Also confusing: does the internet have a self? Does it need self to be confused?) For example, you could ask the internet ...

  • Case Study: Glastonbury Festival - Noise Monitoring At Glastonbury Festival

    In 1970, an entrance fee of just 1.00 would have permitted you, and about another 1500 'free spirits' to enjoy a weekend of listening to the likes of Quintessence, Marc Bolan and T-Rex, while at the same time savouring the undoubted 'delights' of free raw milk!! Almost three decades later, and at slightly greater expense, you and over 100,000 other people can now enjoy the delights and unique ...

  • Managing Compliance: Taking Stock of Your Regulatory and Product Data in 2012

    As we head into 2012, the regulatory landscape remains volatile and unpredictable. OSHA’s adoption of the Globally Harmonized System (GHS) was announced in March, significant progress is being made on the Safe Chemicals Act and the new requirement to produce REACH exposure scenarios (ES) further burdens manufacturers and distributors who already are struggling to conform to REACH’s ...


    By Verisk 3E

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