SOUND KNOWLEDGE

These articles provide general sound knowledge and explore
sound - a phenomenon so common we rarely appreciate
all of its functions despite it touches nearly all areas of our lives.

Sound Intensity: Theory and Measurements

Sound intensity measurement is a powerful technique that allows us to measure the flow of sound energy as a time-averaged vector quantity. The properties of sound intensity allow us to separate sound sources and to distinguish direct sound from reverberant sound in a room. This guide introduces the subject of sound intensity measurement, including the basic theory, how it is measured in practice, and common applications.

Essais de bruits de passage réalisés à l'intérieur : une solution à un problème extérieur

Les essais de bruits de passage réalisés à l'intérieur aident les équipementiers automobiles à respecter les nouvelles limites de bruit, mais aussi à étudier et à optimiser leurs designs de manière rentable.

Pass-by Noise Regulations – Meet the Latest Indoor Standards

To avoid excessive traffic noise in urban environments, pass-by noise measurements are mandatory to meet the strict regulations for vehicle noise certification. As of December 29, 2018, homologation and conformance of production for cars, buses and trucks by indoor pass-by measurement is now allowed.

Testing Futuristic Fighter Jets

Collaborating with Lockheed Martin for many years, Brüel & Kjær is supporting the demand for ‘right-first-time’ engineering and supplying reliable, high-quality, goal-focussed solutions for noise and vibration testing and analysis. This partnership is helping ensure the high performance of some of the most technologically sophisticated machines ever built.

Sound Intensity and Sound Power Relationship

Que sont la puissance acoustique et la pression acoustique ?

La puissance acoustique correspond à l’énergie sonore totale émise par une source acoustique par unité de temps. La pression acoustique est, en revanche, le résultat de l’émission d’énergie sonore par des sources qui rayonnent dans un environnement acoustique spécifique et est mesurée en un point précis. La puissance acoustique est la cause et la pression acoustique est l’effet.

Class-D technology: Enhancing sound quality

Class-D audio systems are the practical choice when you need more audio power.

The Longest Reverb

In 2014, acoustics expert Trevor Cox crawled through a narrow pipe into a subterranean oil tank in Inchindown, Scotland. One gunshot and 75 seconds later, he had set a new world record for the longest echo in a man-made structure. Learn more about reverberation time, and listen to the record-holding gunshot in the underground chamber.

Anatomie de l’oreille humaine

L’oreille humaine est un système complexe composé de trois parties distinctes, chacune jouant un rôle spécifique dans le processus de captage et d’analyse du son.

Étude approfondie de la cochlée. - L'anatomie de l'oreille humaine, partie 2

Ce deuxième article sur le thème l'anatomie de l'oreille humaine est consacré au processus de transformation des sons provenant de vibrations mécaniques en signaux neurologiques. Nous étudions plus en détail la cochlée et sa fonction par rapport aux cellules ciliées situées dans l’oreille interne et externe qui régissent notre sensibilité auditive.

Philharmonie bestial

Ils rugissent, claquent, frappent, gazouillent et hurlent. Le répertoire des sons et vibrations de ces animaux offre une symphonie fascinante. Essentiels à leur survie, ces étranges et merveilleuses créatures utilisent les sons et les vibrations pour se diriger, chasser, communiquer, séduire leurs partenaires et éloigner les prédateurs.

What is Cavitation?

Cavitation is a primary source of propeller noise. The noise is caused by popping bubbles, sort of. They aren’t air bubbles, and they’re not actually popping. They are imploding bubbles of steam.   

Not so Long Ago in a Movie Right by You....

The sound of explosions, vehicles, weapons, rustling trees and even breathing – in one famous case – are carefully orchestrated elements that can make or break the audience’s immersion. But particular real-life noises might be kind of underwhelming, so where does that perfect sound come from?

Reigniting Guitar Evolution

In Spain, an aura of mysticism surrounds the construction of guitars, with the best concert-level instruments commanding enormous respect.

The Acoustic Properties Of A Ripe Watermelon

Many of our customers are engineers, and the different applications they explore outside the scope of their daily work are quite extraordinary.

Sound Art in Extremis: Mapping The Sound Ecology of Antarctic Weather

Sound artist and RMIT University academic, Dr Philip Samartzis, travelled to the Antarctic’s Casey Station as an Australian Antarctic Arts Fellow in early 2016, to explore the interaction of katabatic wind with the built and natural environments.

Fusing Form and Function In Room Acoustics

Keith Yates and his team have been engineering purpose-built director screening rooms and private theatres for 26 years, serving an international client base that ranges from well known directors, to private, unknown movie lovers.

AIISH - Developing Speech and Hearing

The All India Institute of Speech and Hearing (AIISH) develops methods for assessing and rehabilitating people with communication disorders all across India.

The Father of Dolby Technology

Learn about the pioneering legend who revolutionized the recording industry with Dolby Technology in this article.

The Next Generation of Sound

Future challenges of electric vehicle noise control.

Savings in The Pipeline

According to the EU, one of our most promising untapped sources of renewable energy is the energy we can save by mitigating leakage and waste. Arne Jensen is at the forefront of harnessing wasted energy with his acoustic technology that detects and stops leakage in district heating systems – before it even begins.

Wavelength to Frequency, and the Speed of Sound

When you play music through a loudspeaker, the loudspeaker’s membrane is set in motion, alternately moving in and out. On its way out, the membrane compresses the air right in front; when moving back into the loudspeaker cabinet, it leaves more space for the air in front, causing it to rarefy.

Anechoic Chambers: MSC Application Resarch Center (ARC)

For the past decade, the MSC Application Research Center (ARC) - a unique noise and vibration solution facility - has provided state-of-the-art NVH testing capabilities for a broad range of projects. This year, the ARC, located just outside Detroit, Michigan, celebrates its 10th anniversary.

Le silence est en marche

Historiquement, les mesures de bruit au passage sont exigées pour tous les constructeurs automobiles dans le cadre de la certification de leurs véhicules. Les procédures de mesure sont définies par des normes nationales et internationales afin de respecter les niveaux de bruit, mais les choses évoluent. Le développement de véhicules électriques (VE) et hybrides (HV) particulièrement silencieux implique des changements et des défis qui dépassent la simple problématique du mode de propulsion. En effet, le...

Exterior Noise Of A High-Speed Train

Transport by high-speed train is becoming more widespread particularly in these climate-conscious times. How can the external noise from these moving sources be efficiently measured and assessed?

My car. My engine. My sound

There’s not a cloud in the sky, and the empty highway beckons through your windshield. You nudge the pedal closer to the floor, and the roar of the engine feels like joy. But who decides how that roar sounds?

All quiet on board

Noise is a significant issue for anyone working on ships. Even moderate noise and vibration can affect comfort and lead to a drop in performance. Professor Hideyuki Shuri, an authority on ship noise, has been working for many years to overcome the challenges.

Predicting EV Warning Sounds

Electric vehicles (EVs) are so quiet at low speeds that they can be a danger to pedestrians, cyclists, and other road users. So the challenge for car manufacturers is to create sounds that are detectable but not annoying.

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