Experimental Acoustics
Cooper Union faculty and students take advantage of our location in New York City pursuing research projects in experimental acoustics, noise monitoring and control. Students take sound data from our HVAC equipment and evaluate the room acoustics of spaces in our state-of-the-art 41 Cooper Square academic building, in the Great Hall of our landmarked Foundation Building, and in our community. Students have access to industry standard data acquisition equipment and the anechoic chamber in our Vibration and Acoustics Laboratory. We are developing protocols and evaluating low-cost microphones and sound measurement systems for use in various applications including speech language pathology, urban noise monitoring and architectural acoustics.
Sounds of New York City, Urban Acoustic Monitoring and Deciphering the Code
New York City’s sound environment can be perceived as vibrant and energetic or loud and disturbing. Citizen complaints registered with the NYC 311 information/complaints line establishes noise as a major quality-of-life issue; although not all noise issues are reported. Cooper Union students are gaining a deeper understanding of the urban sound environment, the NYC Noise Code, and how noise complaints are addressed and mitigated. Students have taken sound level measurements in a number of East Village apartments and compared these measurements to the noise code.
Cooper Union is also collaborating with the NYU Center for Urban Science + Progress on the Sounds of New York City (SONYC) project to evaluate the frequency response of low-cost, acoustic sensing devices for monitoring the urban sound environment of New York City. To learn more, below is a link to a Sounds of New York City video submitted to the 2015 NYC BigApps Competition:
Related Publications:
Mydlarz, C., Shamoon, C., Baglione, M., Pimpinella, M., "The design and calibration of low cost urban acoustic sensing devices," 10th European Congress and Exposition on Noise Control, May 31-June 3, 2015, Maastricht, Netherlands. Best Paper and Presentation Award.
Evaluating Low-cost Speech-Language Pathology Measurement Systems
Mike Pimpinella (M.Eng. '16)
Speech-Language Pathology focuses on the diagnosis, treatment, and post-therapy assessment of communication issues arising from diseases and disorders such as Parkinson's disease, strokes, cleft palates, and more. This relies on the recording and measurement of voice with microphones and sound level meters (SLMs) for the determination of voice perturbation metrics and vocal intensity measurements. This thesis involves the development of test and analysis protocols for comparing measurements acquired with low-cost options to those obtained with calibrated equipment designed for measurement purposes. These methods will be applied to a selection of low-cost microphones and sound level meters to determine whether they are suitable as substitutions for precision instrumentation. The performance characteristics are compared to a set of guidelines developed by experts in the field.
Related Publications:
Oliveira, G., Fava, G., Baglione, M., Pimpinella, M., “Mobile Digital Recording: Adequacy of the iRig and iOS device for Acoustic and Perceptual Analysis of Normal Voice,” Journal of Voice, March 2017, Vol. 31 (2), 236-242.
Fava, G., Oliveira, G., Baglione, M., Pimpinella, M., Spitzer, J., "The Use of Sound Level Meter Apps in the Clinical Setting," American Journal of Speech-Language Pathology, February 2016, Vol. 25, 14-28.
Acoustic Properties of Auditoriums
Yueyue Li (ME '18), Independent Study Project
Reverberation time is an important indicator for a room’s acoustics; it is the time it takes for a 60 dB sound decay. Analyzing the reverberation time can reveal which functions are most suited for a particular space. The Interrupted and Impulse Methods were used to measure the reverberation time in The Great Hall and Rose Auditorium. The Interrupted Method involves an omnidirectional speaker playing white or pink sound, and the Impulse Method uses a balloon-pop as a triggering sound source. A Larson-Davis 831 sound level meter is used to measure the decay of different frequency sound and to calculate the reverberation time. The average reverberation time is 1.43 seconds for The Great Hall and 0.709 seconds for Rose Auditorium. Considering the volumes of the two auditoriums, The Great Hall is best suited for concerts, while Rose Auditorium is best for speeches.
Acoustic Characterization of 41 Cooper Square
Jacob Fern (ME '11), Senior Capstone Design Project
The acoustics of Cooper Union's 41 Cooper Square building were tested for two di fferent acoustical parameters: reverberation time and ambient sound levels. These measurements were compared with ANSI/ASA S12.60-2010.
Based on the overall ambient sound pressure level and reverberation time measurements, 41 Cooper Square does not meet ANSI standards for academic acoustical characteristics. Although most rooms were just below
the maximum limit for reverberation times of 0.7 seconds, almost every room that was tested failed to fall below the
ANSI standard for the ambient sound levels of the room. In many cases, this was due to external noise from the city, and in almost all cases, the HVAC system seemed to be at fault. Click here for final report. Click here for poster.
Musical Instrument Design and Analysis
Investigating the Suppression of Mid-Range Harmonics in Violins
Stephanie Kwan (Stuyvesant High School 2013-2014), 2014 New York City Science and Engineering Fair and Intel Science Search project, Co-advised by David Tan (ME’14)
The development of a way to alter an ordinary violin to improve its sound quality has implications in the music industry and the education sector. A simple way of improving a violin’s sound will give more students the chance to play and own high-quality violins that they otherwise couldn't afford. Building on prior findings by a researcher named William F. Fry, this experiment investigates his claim that removing wood from the interior of a violin at certain locations (called Stradivari Holes #2, #3, and #4) will alter the vibrational characteristics of the violin, and suppress shrill, undesirable harmonics in the violin’s sound. An original experimentation setup was designed to meet the needs of this project. A violin was bowed by an automated machine inside an anechoic chamber, and 1/24th octave band analysis was applied to the microphone data in order to determine the violin's frequency content. The peak amplitudes of the frequencies were computed, and the frequencies falling in the mid-range of 1500 Hz - 4000 Hz were compared before and after the alteration to the violin's structure. Click here for NYCSEF report.
Additional musical instrument design and analysis student projects can be found on the Advanced Vibrations (ME401) website.
Other example acoustics, vibration and noise control student projects can be found on the Acoustics (EID260) and Vibrations (ME301) websites.