Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Measurement scientists set a new standard in 3-D ears

13.10.2010
'HATS' off to the National Physical Laboratory for innovation in sound measurement

Scientists at the UK's National Physical Laboratory (NPL) have developed a means of representing a 3D model ear, to help redefine the standard for a pinna simulator (the pinna is the outer part of the ear) – used to measure sound in the way we perceive it.

The nature of human hearing is heavily dependent on the shape of the head and torso, and their interaction with sound reaching the ears allows for the perception of location within a 3D sound field.

Head and Torso Simulators (HATS) are designed to model this behaviour, enabling measurements and recordings to be made taking account of the Head Related Transfer Function (HRTF) - the difference between a sound in free air and the sound as it arrives at the eardrum.

HATS are mannequins with built-in calibrated ear simulators (and sometimes mouth simulators), that provide realistic reproduction of the acoustic properties of an average adult human head and torso. They are ideal for performing in-situ electro-acoustic tests on, telephone handsets (including mobile and cordless), headsets, audio conference devices, microphones, headphones, hearing aids and hearing protectors.

Critically the shape of the pinna has a large effect on the behaviour, and as a result it is defined for HATS by its own standard (IEC TR 60959:1990) to provide consistency across measurements. However, this standard defines the shape of the pinna through a series of 2D cross-sectional profiles. This form of specification and definition has on occasion proven to be an inadequate guide for manufacturing processes.

As part of a revision of this standard, the Acoustics Team at NPL teamed up with the National Freeform Centre in a novel move to redefine the standard through an on-line 3D CAD specification. A model ear was measured using a coordinate-measuring machine with laser scanner to produce a 3D scan of the ear, which can then be used to provide manufacturers with a more practical specification for reproduction and a standard that is easily comparable with similar non-contact freeform measurement techniques.

Ian Butterworth from NPL, said:

"Having a 2D pinna in an artificial ear has some inherent frequency limitations. For example, when sound spreads through structures like narrow tubes, annular slits or over sharp corners, noticeable thermal and viscous effects take place causing further departure from the lumped parameter model. The new standard for the 3D model has been developed to give proper consideration to these effects. We worked with the National Freeform Centre, experts in measuring items that are unconventional in shape or design, to develop the new standard – which will now help manufacturers develop better products."

The National Physical Laboratory

The National Physical Laboratory (NPL) in Teddington is one of the UK's leading science facilities and research centres. It is a world-leading centre of excellence in developing and applying the most accurate standards, science and technology available.

NPL occupies a unique position as the UK's National Measurement Institute and sits at the intersection between scientific discovery and real world application. Its expertise and original research have underpinned quality of life, innovation and competitiveness for UK citizens and business for more than a century:

NPL provides companies with access to world leading support and technical expertise, inspiring the absolute confidence required to realise competitive advantage from new materials, techniques and technologies.

NPL expertise and services are crucial in a wide range of social applications - helping to save lives, protect the environment and enable citizens to feel safe and secure. Support in areas such as the development of advanced medical treatments and environmental monitoring helps secure a better quality of life for all.

NPL develops and maintains the nation's primary measurement standards, supporting an infrastructure of traceable measurement throughout the UK and the world, to ensure accuracy and consistency.

The National Freeform Centre at NPL

The National Freeform Centre at NPL supports UK end-users, manufacturers and academics in freeform measurement by providing evaluation and traceability for CMMs with tactile and non-contact probes, laser scanners, articulated arms, fringe projection systems, and point cloud processing software. Examples of the gains potentially achievable with suitable advances in freeform manufacture include efficiency of aero engines, drag reduction for automotive bodies and increased life span of prosthetics.

Efficiency of aero engines, drag reduction for automotive bodies and increased life span of prosthetics are just some examples of the gains potentially achievable with suitable advances in freeform manufacture. However, such advances are partly limited by poor metrology infrastructure, lack of measurement traceability and absence of specialised facilities and knowledge base.

Joe Meaney | EurekAlert!
Further information:
http://www.npl.co.uk

More articles from Physics and Astronomy:

nachricht New NASA study improves search for habitable worlds
20.10.2017 | NASA/Goddard Space Flight Center

nachricht Physics boosts artificial intelligence methods
19.10.2017 | California Institute of Technology

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Neutron star merger directly observed for the first time

University of Maryland researchers contribute to historic detection of gravitational waves and light created by event

On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...

Im Focus: Breaking: the first light from two neutron stars merging

Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.

Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....

Im Focus: Smart sensors for efficient processes

Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).

When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...

Im Focus: Cold molecules on collision course

Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.

How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...

Im Focus: Shrinking the proton again!

Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.

It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ASEAN Member States discuss the future role of renewable energy

17.10.2017 | Event News

World Health Summit 2017: International experts set the course for the future of Global Health

10.10.2017 | Event News

Climate Engineering Conference 2017 Opens in Berlin

10.10.2017 | Event News

 
Latest News

Terahertz spectroscopy goes nano

20.10.2017 | Information Technology

Strange but true: Turning a material upside down can sometimes make it softer

20.10.2017 | Materials Sciences

NRL clarifies valley polarization for electronic and optoelectronic technologies

20.10.2017 | Interdisciplinary Research

VideoLinks
B2B-VideoLinks
More VideoLinks >>>