Hall 3 / Stand no: C3
GRAS Sound & Vibration UK Ltd (GRAS UK) will be highlighting its wide range of cutting edge measurement microphones and related acoustic accessories, including pre-amplifiers and signal conditioning devices. The company will be showing its newly launched KB5000/5001 right and left pinnas with anthropometric concha and ear canal for use with the 43BB low noise, highly sensitive ear simulator system designed to measure sound pressure levels close to or below the threshold of human hearing. The compact flush mount turbulence screen microphone kit, specially designed to enhance noise measurement for the automotive and aerospace sectors, will also be on display.
With consumers continually demanding a better sound experience from headphone technologies, GRAS UK has introduced the KB5000/KB5001 right and left anthropometric pinnas for better measurement at low frequencies, including Active Noise Cancellation below 1 kHz. The low frequency response is accurate every time allowing reduced test time whilst maintaining reliable measurements. Produced from soft silicone, the external shape of the pinna is identical to others on the market but the concha and canal have been modified so that they closely mimic the properties of a real human ear.
The GRAS UK 43BB has a very low noise floor – below 10.5 dB (A) – and has been developed to meet the consumer electronics industry’s need for R&D testing of headphones, especially in-ear systems with Active Noise Cancellation. Because it is capable of measuring down to and below the threshold of human hearing, it can assess the influence of the electronics on the audio response of the earphones. The low inherent noise of the 43BB also means that correlation to subjective listening results is extremely good, and that THD and rub and buzz at very low levels can be investigated.
Demonstrating its commitment to helping aircraft and motor vehicle manufacturers further reduce noise emissions, GRAS UK’s flush mount turbulence screen microphone kit significantly improves aeroacoustic testing in wind tunnels. With noise development having a considerable effect on a vehicle’s comfort and economy, the simple, robust and reliable flush mount turbulence screen microphone kit has been specially developed for accurate testing in solid walled wind tunnels in the near and far field, at low and high wind speeds. By attenuating the hydrodynamic component of turbulence up to as much as 25 dB, the acoustic signals of interest can now be identified and diagnosed with a much more reliable resolution.
The turbulence screen integrates the flush and recessed mounting techniques with a special wire mesh into one single unit and allows for adaptation of several mounting options. It comprises a state-of-the-art 47BX / ¼” flush mount microphone set which combines high precision and reliable noise measurement with the need for fitting sensors into very confined spaces and narrow structures. With an installation height of less than 10mm, thin coax wiring and front venting, this flush mount microphone can be integrated into literally any design and application.
In addition, the kit offers a turbulence frequency range between 500Hz – 10KHz; acoustic attenuation less than 3db; acoustic frequency range between 100Hz – 70kHz; dynamic range between 44dBA – 166dB; approach ±90 degrees and front venting.
GRAS UK’s aeroacoustic toolbox also includes surface microphones which are highly suited to in-flow testing of full scale objects in wind tunnels. The company’s nose cones are the result of a development project with German Dutch Wind Tunnel and offer superior in-flow noise rejection compared to existing designs.
In addition, the company is highlighting its 46AE microphone sets. Manufactured from stainless steel to ensure superior stability and less sensitivity to fluctuations in temperature, the 46AE is a plug and play IEEE 1451.4 accredited system. The underlying mechanism for plug and play identification is the standardisation of a Transducer Electronic Data Sheet (TEDS1).The 46AE sets are IEPE/ICP compatible which means that they can be connected directly to a range of front ends for easy set up.