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GFI Test Technologies (CT, MA, ME, NH, RI, VT)

PO Box 320

MA 01929 Essex

+1 978-801-3114

GRAS worldwide


Since its establishment in 1994, GRAS has been totally dedicated to the development and manufacture of high-quality measurement microphones and related acoustic equipment.  It was founded by the Danish acoustics pioneer, Gunnar Rasmussen, who has been a major contributor 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, Gunnar’s ingenuity and foresight led to the world’s most popular acoustic sensor:  the ½” measurement microphone.  The ¼” 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 for the years; all based on Gunnar’s original 1” pressure microphone design.



GRAS NA, Inc. was established in May 2002. As a subsidiary of GRAS Sound & Vibration A/S in Denmark, our main goal is to provide excellent customer service and support as well as grow the GRAS experiences in the United States.

Ed Okorn

Ed Okorn

General Manager NA


Robert K. O’Neil

Applications Engineer


Bob joined GRAS Sound & Vibration in 2013 as a general Field Applications Engineer.

Bob has many years of experience in Ultrasonics, working with polycrystalline piezo ceramic and single crystal PMN-PT materials. Bob has degrees in both Physics and Electrical Engineering with many graduate classes such as MEM's, Finite Element Analysis, Optics, Acoustics, Continuum Mechanics, and Transducers from several fields of study. His primary interest is in transducers, their performance and how they solve the customers’ challenges/application.

His focus is to support our Industry Managers, Sales Partners and customers in any application. Bob spends a lot of time with telephone support, testing and calibration in our in-house calibration lab and visiting customer with local sales partners.