Acoustical Engineer providing consultation and training in innovative methods and solutions for Product Sound Quality
EXAMPLE INNOVATIONS:
Percentile Frequency Method for Relative Frequency Content Evaluation Summed Exceedance Measure for Specifying Impulsive Sound Frequency Content Relative Pitch Evaluation of Variations in Tones from Electrically Powered Systems Music Analogy Requirement Strategy for Product Sound Quality
EMPLOYMENT HISTORY: April 1993 to May 2006(retired): General Motors Corp., GM Proving Grounds, Milford, MI Development Engineer: Noise and Vibration Center
Developed Sound Quality (SQ) measures for evaluating vehicle sounds, with emphasis on Customer Actuated Sounds (CAS) (i.e. power windows, power mirrors, door closings, etc.) especially impulsive sounds. Developed basic requirement strategy using the Music Analogy for SQ. Developed sound tests and specifications for frequency content and loudness as time-varying functions for shifter operations, door latches, solenoids and relays in shifters. Developed relative pitch specifications and evaluation methods for electrically powered CAS systems. Earned a DFSS Green Belt by participating in a Door Closing Sound Quality Project. Evaluated vehicle interior noise packages for GM trucks and cars. Evaluated vibration damping materials and assisted in selection and optimization using predictive methods. Developed method for evaluating material "itch" noise.
December 1982 to April 1993: General Motors Corp., GM Technical Center, Warren, MI Development Engineer: Product Testing Laboratory (1990 – 1993) Senior Experimental Engineer: (1985 - 1990) Experimental Engineer: (1982 - 1985)
Invented the Percentile Frequency method for evaluating the sound quality of door closing sounds (and impulsive sounds in general). Developed test methods and specifications for power accessory noise based on Zwicker Loudness. Introduced state-of-the-art testing methods and computerized sound absorption and vibration damping tests. Tested for acoustical properties of materials used in GM cars.
May 1981 to December 1982: General Motors Corp., GM Technical Center, Warren, MI Environmental Activities Staff Project Engineer: International Regulations Department
Analyzed regulations for possible areas of harmonization. Established computer database on foreign regulations and compliance interpretations.
November 1978 to May 1981: General Motors Corp., Environmental Activities Staff Environmental Activities Staff Project Engineer: Product Noise Control Department
Provided technical support for corporate positions on government noise control regulation proposals. Measured community traffic noise for math model verification. Performed property-line plant noise measurements and analysis. Helped develop an in-door, all-weather test procedure for trucks.
June 1976 to March 1978: Applied Research Lab, Pennsylvania State University, State College, PA Research Graduate Assistant: Interdisciplinary Acoustics Program
Performed research necessary for Master's thesis.
March 1974 to August 1975: Walker-Williams Assoc., Cleveland, OH Technical Contract & Consulting Services Consultant in Acoustics:
Performed industrial noise surveys, acoustical qualification testing and reverberation time measurements. Wrote original equipment noise control design specifications. Reduced in-cab noise in diesel trucks.
EDUCATION: 1966-1970 John Carroll University, Cleveland, OH Bachelor of Science in Physics
1970-1973 John Carroll University, Cleveland, OH Additional Study: Physics, Acoustics, Math
Aug. 1972 University of Michigan, Ann Arbor, MI Noise Reduction in Mechanical Systems: (summer program)
1976-1978 Pennsylvania State University, State College, PA Master of Science in Acoustics
Thesis: Reverberation Time Measurements in an Underwater Chamber with and without a Pressure Release Wall Covering
Academic Honors: Phi Kappa Phi Honor Society
PROFESSIONAL ORGANIZATIONS: Acoustical Society of America -- member Institute of Noise Control Engineering -- member SAE -- member (serving on Acoustical Materials committee – sponsor for revision of damping standard J1637) ASTM -- member - E33 Environmental Acoustics (Chair of Damping Task Group for revision of standard E756)
PUBLICATIONS: Documenting a Career of Continuing Innovation
1979, E.C. Andrews and R.J. Fridrich, The Effect of Wall Coverings on Acoustic Characteristics of a Water-Filled Test Chamber, U.S. Navy Journal of Underwater Acoustics, October 1979.
1984, R.J. Fridrich, Computer Data Acquisition from B & K Digital Frequency Analyzers 2131 / 2134 Using Their Memory as a Buffer, Bruel & Kjaer Technical Review, No. 4 - 1984
1991, R.J. Fridrich, Investigating Calculated Loudness ISO 532 for Evaluating Impulsive Sounds, Proceedings of the 1991 Noise and Vibration Conference, Society of Automotive Engineers, No. 911088, May 1991.
1993, R.J. Fridrich, Investigating Impulsive Sounds -- "Beyond Zwicker-Loudness," Proceedings of the 1993 Noise and Vibration Conference, Society of Automotive Engineers, No. 931329, May 1993.
1996, P.C. Wang and R.J. Fridrich, Influence of Thermal Aging on the Damping Properties of an Acrylic-Cored Laminated Steel, Journal of Composite Materials, Vol. 30, No. 15 / 1996.
1997, R.J. Fridrich, Pitch Matching for Impulsive Sounds, Proceedings of the 1997 Noise and Vibration Conference, Society of Automotive Engineers, No. 971981, May 1997.
1997, P.C. Wang and R.J. Fridrich, Influence of Thermal Aging on the Damping Properties of a Resistance Spot-Welded Acrylic-Cored Laminated Steel, Welding Research Journal (Supplement), October 1997.
1999, R.J. Fridrich, Percentile Frequency Method for Evaluating Impulsive Sounds, Proceedings of the 1999 Noise and Vibration Conference, Society of Automotive Engineers, No. 1999-01-1851, May 1999.
2002, R.J. Fridrich, Percentile Frequency Method and Zwicker Loudness, Proceedings of the 2002 International Congress on Noise Control Engineering, August 2002.
2003, R.J. Fridrich, Pitch Intervals: Linking Sound Quality Engineering and Musical Acoustics, Proceedings of the 2003 Noise and Vibration Conference, Society of Automotive Engineers, No. 2003-01-1503, May 2003.
2003, Hua He, Qijun Zhang and R.J. Fridrich, Vehicle Panel Vibro-Acoustics Behaviors and Damping, Proceedings of the 2003 Noise and Vibration Conference, Society of Automotive Engineers, No. 2003-01-1406, May 2003.
2005, R.J. Fridrich, Music Analogy: An Alternative Strategy for Sound Quality Requirements, Proceedings of the 2005 Noise and Vibration Conference, Society of Automotive Engineers, No. 2005-01-2477, May 2005.
2007, R.J. Fridrich, Measuring the Pitch of Door Closing Sounds – The Sound Quality Issue of Door “Thump”, Proceedings of the 2007 Noise and Vibration Conference, Society of Automotive Engineers, No. 2007-01-2216, May 2007.
2007, R.J. Fridrich, Is This Room Anechoic? A New Anechoic Room Qualification Standard May Be Needed for Impulsive Sound Quality Tests, Proceedings of the 2007 Noise and Vibration Conference, Society of Automotive Engineers, No. 2007-01-2217, May 2007.
POSTER PRESENTATIONS:
1989, Loudness Calculation (ISO 532) for Evaluating Components and Vehicles, 1989 Noise and Vibration Conference, Society of Automotive Engineers, May 1989.
