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.

音響インテンシティ：理論と測定

音響測定と音響理論は、常に隣り合わせで進んできたわけではありません。現代の音響学の基礎を築いたのは、レイリー卿の名著「The Theory of Sound」の出版でした。この理論の基礎となるのが、音響インテンシティという物理量です。しかし、十分実用的な音響インテンシティの測定方法が登場するまでには、それから実に100年もの歳月が必要でした。

インドアパスバイ：屋外試験における問題の解決策

インドアパスバイ試験は、車両OEMが新しい騒音規制値に準拠するためだけでなく、費用効果の高い方法で設計を調査し、最適化するのに役立ちます。

通過騒音規制-最新のインドアパスバイ規格に適合

都市環境での過度な交通騒音を防ぐことを目的とした、車両騒音認証の厳しい規制を満たす通過騒音の測定が義務付けられています。 2018年12月29日現在、インドアパスバイ測定による自動車、バス、トラックの認証試験および生産の適合性検査が認められています。

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

音響パワーと音圧

音響パワーとは、単位時間あたりに音源が放射した空気中の音響エネルギーの総量です。一方音圧は、音源が放射した音のエネルギーが、その場の音響環境の影響を受けて測定された物理量です。音響パワーは原因、音圧は環境の影響を受けた結果といえます。

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.

人間の耳のしくみ

人間の耳の構造は複雑で、聴覚系とも呼ばれます。三つの異なる部分から成り、それぞれが音を収集して分析するための特定の役割を担っています。外耳では音を収集、内耳では音を脳が処理できる神経信号に変換、そして中耳では鼓膜で音響結合をします。

Cochlea Function: A Closer Look at the Ear

In this second article on the anatomy of the human ear, we look at the process of transforming sound from mechanical vibrations into neurological signals. We take a closer look at the cochlea, and the cochlea function in relation to the hair cells located in the inner and outer ear that control our hearing sensitivity.

The Fauna Philharmonics

They howl, thump, bang, chirp and rumble. The sound and vibration repertoire of these animals would indeed make an interesting symphony. Key to their survival, these weird and wonderful creatures use sound and vibration to navigate, hunt, communicate, attract mates and ward off predators.

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.

極限のサウンドアート：南極の気象で「音の生態」をマッピング

サウンドアーティストでRMIT大学の学者であるPhilip Samartzis博士は、2016年初頭にAustralian Antarctic Artsのフェローとして南極のケイシー基地を訪れ、そこでカタバ風（カタバティック風、斜面降下風）と構造物、自然環境の相互作用を調査しました。

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.

Something quiet this way comes

Traditionally pass-by noise measurement is a requirement for all automotive manufacturers as part of product certification, with measurement procedures defined in local and regional standards to ensure that noise levels are not exceeded, but times change. The introduction of extremely quiet electric vehicles (EVs) and hybrid vehicles (HVs) introduces more changes and challenges than just a different propulsion method; ‘too loud’ now only covers half of the problem.

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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