Since the establishment in 1994, G.R.A.S. have been 100% dedicated to developing and manufacturing high-quality measurement microphones and related acoustic equipment.
Since the establishment in 1994, G.R.A.S. have been 100% dedicated to developing and manufacturing high-quality measurement microphones and related acoustic equipment. We are founded by the Danish acoustics pioneer Gunnar Rasmussen who for more than 60 years has contributed to the world of sound and vibration with his unique ideas and designs. From the first reproducible 1” condenser measurement microphone that enabled quality measurements and instrumentation for acoustic calibration, Mr. Rasmussen’s ingenuity and foresight led to the world’s most popular acoustic sensor: The 1/2” measurement microphone. Then the 1/4” and 1/8” microphones followed with outstanding dynamic and high-frequency capability that brought higher definition and transparency into impulse noise diagnostics. Many variants have been made available over the years; all based on Gunnar Rasmussen’s original 1” pressure microphone design.
When celebrating our 20 years' anniversary in 2014 we documented the story of our founder, Gunnar Rasmussen. Order your copy of the G.R.A.S. jubilee book.
At G.R.A.S., we and our customers benefit daily from Mr. Rasmussen’s exceptional understanding of acoustics, physics, electronics and measurement needs. Not only in R&D but throughout the organisation, we are proud to develop, produce and offer the world's best measurement microphones and accessories. And as a family company, now owned and led by the two sons, Per Rasmussen and Peter Wulf-Andersen, we safeguard our heritage and knowledge to help create new opportunities with our customers. We work with everybody with an interest in sound or noise within the fields of aerospace, automotive, audiology, consumer electronics, noise monitoring, building acoustics and telecommunications, metrology, education, consultancy, legislation and system integration.
When our R&D team develops a measurement microphone, it must undergo the most demanding tests to prove that it deserves to bear the G.R.A.S. name. Using a series of “Highly Accelerated Life Tests” we ensure that our microphones live up to the high quality and precision that our customers have come to expect and trust. Our HALT tests actively accelerate the lifetime of a microphone by simulating the handling and use it is exposed to in real life situations.
We bake it, we humidify it, we shake it and we even try to break it, just to make sure that you get the very best measurement results every time. Learn more about our microphone HALT testing here.
All our microphones are solely produced in stainless steel and in a quality that allows for a 5 year warranty. Should you by mistake damage the diaphragm on a G.R.A.S. microphone, our special technique enables repair at very reasonable price.
G.R.A.S. is ISO 9001:2008 certified.
The 42AC is an extremely stable laboratory standard sound source which can also be used for field calibrations – it retains its high accuracy even under hostile environmental conditions.
The G.R.A.S. 43AG Ear and Cheek Simulator is a unique, multi-faceted and multi-purpose tool that helps you accomplish the job in an effective and efficient manner. We call it the table-top KEMAR as it offers you much of the KEMAR capability in a convenient and portable packaging.
KB5000 is a right pinna with anthropometric concha and ear canal for KEMAR. It is made of soft silicone, 35 Shore OO hardness.
Proper use of a microphone with a nosecone is to aim the nosecone towards the air flow. The nosecone has an inner threading and is installed by replacing the protection grid with the nosecone. G.R.A.S More Details: Nosecone
The G.R.A.S. 43BA-2 A high frequency 1/4" 0.4cc coupler kit for test of hearing aids at frequencies up to 16 kHz. It is a complete kit with a 1/4" Pressure Microphone and a 1/4" Preamplifier with BNC connection and the same adapters known from the reference 2cc coupler. (Coupler) More Details: G.R.A.S. 43BA-2
Typical applications and use Very Low Sound pressure measurements Lownoise product measurements Lowlevel Sound power measurements Measurements on hard-disk drives, computer products, quiet rooms etc. G.R.A.S.
The G.R.A.S. 47AC is a 1/2" CCP precision condenser microphone set for infra-sound measurements in open acoustic fields.
The G.R.A.S. 42AG Multifunction Sound Calibrator is a portable, battery operated sound source for calibration and check of microphones and sound level meters. It is designed for field use and comes with a protective casing. It conforms to the requirements in IEC 60942 for a class 1 sound calibrator.
The G.R.A.S. 46DE is a 1/8'' CCP Pressure Microphone Set. The preamplifier is 1/8", making it the world's smallest microphone set. --- Frequency Range : 6.5Hz to 140kHz Dynamic Range : 47 dB(A) to 175dB Sensitivity : 0.62 V/Pa