The international standard IEC 60318-4 specifies an occluded ear simulator, often referred to as a 711-coupler, for testing headphones, earphones, hearing protectors, hearing aids etc. The standard specifies a specific microphone type which limits the dynamic range of the coupler both in the low range and in the high. To overcome these limitations, G.R.A.S. has developed two modified versions of the standard ear simulator: A high-sensitive, low-noise version that extends the lower dynamic range below the threshold of human hearing, and a high-pressure version that extends the upper dynamic limit to 178 dB. Also, a new anthropometric ear canal and pinna is introduced. With these, measurements not possible with the standardized configuration can now be made with confidence.
- G.R.A.S. Sound & Vibration A/S
- Two Modified IEC 60318-4 Ear Simulators for Extended Dynamic ...
Verification of CFD tool for simulation of cavitating flows in hydraulic systems
Cavitation is an undesirable phenomenon in hydraulic systems, as it causes erosion and noise. The main difficulty in cavitation prediction when using Fluent software is lack of an openly accessible tool for implementation of a freely chosen homogeneous cavitation model. In this paper the main challenge is to make such a tool, user defined function (UDF). The second challenge is to use a qualitative method in the assessment of the results of verification process. Three cavitation models are verified in Fluent...
Designing that unique Ferrari sound using NVH Simulation
Our NVH simulation technology enabled Ferrari to perform virtual evaluations of alternative design decisions in an interactive, free-driving scenario. Ferraris are distinguished by a unique sound that is as carefully tuned as a piece of music. Creating this characteristic sound authentically and yet keeping it within legal limits requires careful component design and selection. Our NVH simulation technology enabled Ferrari to perform virtual evaluations of alternative design decisions in an interactive, free-drivi...
Romax Consultancy Services Provide Reliability Solutions for European Rail OEM - Case Study
CAF MiiRA is a leading company in the design, manufacture and maintenance of railway wheelsets and their components. Currently, CAF MiiRA is the only manufacturer of wheels and axles capable of delivering the wheelset with a complete design: from the wheels, axles, axle boxes, and gearboxes. Mikel Oyarbide, Gearboxes Projects Engineer at CAF MiiRA, explains: “CAF offers comprehensive global rail solutions which, in addition to the supply of trains, include viability studies, civil work, electrification,...
Engineering Innovation into Driveline Design
Introduction: thinking differentlyWhat is innovation? How can you harness innovation in practical ways to support your business goals? In the driveline industry and for engineering in general, “innovation” is often synonymous with the use of new or novel technologies/methods to achieve design and development goals - and ultimately deliver a higher quality product - in faster, more efficient and lower cost ways. At Romax, we call such an approach Right First Time. It often involves gaining the ability...
How to test phones for noisy environments?
Whether walking down a noisy street or talking on speakerphone, telephone users expect clear voice transmission. Sophisticated signal processing enhances human speech above background noise, but as there are different methods to test this capability, manufacturers cannot always be sure of the best one to use on their products. To identify the best approach, Brüel & Kjær carried out an investigation contrasting five methods for the reproduction of background noise, including ETSI EG 202 396-1,...