RESEARCH ARTICLES

Articles covering all aspects of research within sound
and vibration testing and measurement applications
within a wide range of industries.

Europe’s Largest Refrigeration And Air Conditioning Laboratory

It covers an astounding 8500 square metres, houses an interdisciplinary team of 40 engineers and technicians, has temperatures ranging from +50°C to –40°C and climate chambers big enough to accommodate a refrigerated trailer – welcome to Europe’s largest independent testing laboratory, the Center of Competence for Refrigeration and Air Conditioning.

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.

Structure-borne Sound: Part 1

Previous articles covered the transmission of sound through air and how it is picked up by human hearing. This article addresses sound generation, particularly the vibration of solids and how that leads to sound – using an acoustic guitar as an example.

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.

Technical Review 2017

The Brüel & Kjær ‘Technical Review’ offers a deeper understanding of the many specialized disciplines within sound and vibration. It is where you will find the latest in-depth theory, measurement techniques, and details about specific instrumentation and technology.

Ensuring Stealth With Self-Noise Monitoring

As a world-class naval engineering business, BAE Systems has been working with the UK Ministry of Defence (MOD) to design a new class of frigate: the Type 26 Frigate. To ensure the acoustic stealth of this new class of combat ship, BAE Systems needed a world-class self-noise monitoring system.

Nowhere to Hide

In 1984, we breathed a sigh of relief when we realized that we had not become the totalitarian state described in George Orwell’s novel. There were no thought police, Big Brother wasn’t watching us from giant screens and computing and surveillance technologies were still rudimentary.

Bringing Communities on Board

How Manchester Airports Group’s new noise and operations management system is building trust through transparency.

Cutting-edge Blade Maintenance

Since September 2011, an exciting EUDP project has been underway to develop a practical way to detect, localize and predict damage to wind turbine blades. The associated cost of maintaining and repairing blades is a very real issue for wind farm operators and so far no remote inspection method has offered a viable solution. Thanks to the project, the best answer could lie in sophisticated algorithms using vibration measurements with considerable potential above and beyond the wind industry.

Class-D technology: Enhancing sound quality

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

Good Vibrations - Interview With Doctor Nielsen

What happens when a budding rock star trades in his electric guitar for medical books? In Peter Michael Nielsen’s case, the result is an invention that relieves pain in a unique way.

Listening to the Community

At BHP Billiton, the way results are achieved is just as important as the results themselves, and the impact of mining on surrounding communities is a concern that is taken very seriously. In Western Australia, measures to reduce noise for neighbours to a bauxite mine involved close consultation with the public, monitoring noise at residential locations and creating community forums.

MONICA Takes on Techno

The April issue of WAVES 2018 introduced the MONICA project, and its ambitious plan to help cities use the Internet of Things (IoT) to manage sound and security at large, open-air events. In July 2018, MONICA made its real-world debut: at the Kappa FuturFestival in Torino, Italy.

The Technical Challenges of The Omnidirectional Sound Source

The omnidirectional sound source is the most described and used source in building and room acoustic measurements. Usually, little thought is given to it, yet this seemingly simple device has several interesting aspects of which many may not be aware. Here, we focus on some of the technical challenges we encountered when designing and constructing an omnidirectional sound source.

Not Just a Wind Tunnel

Named after a Danish scientist and passionate inventor recognized for his early work on wind power, the Poul La Cour wind tunnel at DTU Risø Campus, Roskilde Denmark, is among the biggest university-owned wind tunnels in the world.

Outsource or in-house?

For the past 20 years, Pro-Plan Ltd. has provided architectural and engineering services to support sound and vibration testing, including tailor-made, turnkey acoustic test rooms and cabins, on-site training and in-house testing.

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 Fauna Philharmonics

They howl, thump, bang, chirp and rumble. The sound and vibration repertoire of these animals would indeed make an interesting symphony.

Why do Cats Purr? Solving The Mystery!

Ever since the Egyptians started worshipping the cat, philosophers, scientists and cat lovers worldwide have wondered: Why do cats purr? Today, Brüel & Kjær has solved the age-old mystery using accelerometers.

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.

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.

Uplifting Sound Quality

Today, sound is being recognized more and more as an important parameter when defining product quality.

The Purrfect Power

A purring cat is a contented cat, and although that is often the case, cats also purr when injured, frightened or giving birth.

Why do Circadas Chirp? The Sound of Summer

Summer is watermelons, rainstorms, mosquitoes, burning sunshine and air conditioning. But a summer is not a summer without the chirping of cicadas.

Can You Play The Asphaltophone?

When you drive over lumps and bumps on the road, the sounds rumble up into your car. But you might be surprised to learn just how much road makers can control theses sounds.

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.

A Practical Guide to Using MIMO Vibration Control

For MIL-STD-810 single-axis transport testing of large, resonant, land-based military payloads.

The Loudest Sound, Naturally

The loudest sound in recorded history came from the volcanic eruption on the Indonesian island Krakatoa at 10.02 a.m. on August 27, 1883. The explosion caused two thirds of the island to collapse and formed tsunami waves as high as 46 m (151 ft) rocking ships as far away as South Africa.

Realistic Simulation of Background Noise With Multiple Loudspeakers

Whether walking down a street, or multi-tasking with our phone on ‘speaker’, we expect clear voice transmission. Sophisticated signal processing enhances our speech above background noise, but which method is best to test this capability?

Hand-held Arrays In NVH Measurements

Microphone arrays help engineers develop sound quality on vehicles, giving fast and effective noise source identification. Now, advanced new techniques improve the insights possible.

Spy on The Wall

The goodwill gesture that was a master stroke of electronic bugging.

75 Years of Progress

For the past 75 years, visionary engineers and inventors at Brüel & Kjær have been responsible for innovative breakthroughs and many world-firsts. We have a long and impressive track record and, as we look back, we wanted to share with you some of the highlights.

The Screaming Void: An Hour In An Anechoic Chamber

As you walk into an anechoic chamber, you enter a strange new world: spiky, soft walls enclose every surface of the room. And when you look down, the floor is just a see-through mesh. Bouncing on the criss-crossed wires, the atmosphere seems to thicken around you – closing in more than the densest fog.

Prone to Excellence

French engineering student Raphaël Chevalier has developed a device that helps Olympic prone shooters improve their accuracy by up to 24%.

Vibration Analysis Helps Neutrino Experiment

Fermilab is America’s leading particle physics laboratory and operates the world’s most advanced particle accelerators. Scientists use particle accelerators to research some of the least understood particles in the universe: neutrinos. A vibration analysis project recently helped discover the cause of a small fracture in the powerful magnetic horn used to send neutrino beams to Minnesota.

Vibrations in Ice

From building giant ice sculptures in the Rocky Mountains in Colorado to creating Ice Music in Swedish Lapland, Tim Linhart is pushing the boundaries of what can be done with ice.

Multiple Vehicle Pass-by Tests

Engineers can assess noise from many vehicles at the same time with data acquisition synchronized by GPS.

Today's proving ground for vehicles of the future

Mercedes-Benz’ decision to build a new proving ground was spurred by its global target of achieving homologation of all vehicles so that any vehicle will meet or exceed projected global standards regardless of country or region of origin, combined with the need for durability testing.

Vehicle noise tests are getting tighter

The new pass-by tests coming in 2016 will help prevent ‘noisy’ vehicles from being able to satisfy legal sound limits in very specific test conditions – by broadening the scope of the tests.

Leap through jet engine testing

As aircraft engine makers like Snecma address emissions and cost challenges, scalable, high-performance test and analysis systems lie behind their rapid responsel.

Wind Tunnel Vision

High in the French Alps on what could be a James Bond film set, ONERA’s large wind tunnel helps to perfect future aircraft. As they master the challenges of extracting precise acoustic data, ONERA Modane will soon offer a one-stop shop for both aerodynamics and aircraft noise.

Educator and Problem Solver

Growing up in Stockton, a city on the San Joaquin River in California’s Central Valley, Matt Allen’s passion for learning led to a career in research and education. Today, he’s still sharing knowledge and inspiring generations of engineers to come.

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