Acoustics Course Research Articles

Engaging musical acoustics instructors beyond the members of the Acoustical Society of America

The members of the Technical Committee on Musical Acoustics (TCMU) of the Acoustical Society of America (ASA) have demonstrated their commitment to education in acoustics regularly by organizing and cosponsoring numerous education-related sessions at ASA meetings. Musical acoustics as a topic for general education science courses is a popular offering at many colleges and universities. A brief survey of the musical acoustics course offerings at various colleges is presented. Many of these courses are taught by instructors who have not interacted with TCMU members or attended ASA meetings. It is possible that the musical acoustics community is missing out on opportunities to interact with a population of educators who share our interests. Our community should be looking for ways to engage the instructors of musical acoustics courses in dialogue which is mutually beneficial; members of the TCMU may find that they will discover new ideas for teaching musical acoustics from beyond the ASA membership.

Explaining microphones and loudspeakers in a musical acoustics course for non-scientists

Contemporary courses in the field of musical acoustics rely upon basic audio engineering components such as acoustical transducers: microphones, accelerometers, and loudspeakers. Most students are very aware of the practical use and behavior of such devices, but they seldom have a useful understanding of the physical and engineering principles behind the design of these essential components. This paper presents a lesson example explaining microphones and loudspeakers for a general-interest undergraduate college course entitled “The Science of Sound.” The lesson includes a descriptive lecture component, examples and discussion, and a hands-on demonstration.

Standards-based assessment and reporting in introductory acoustics courses

Standards-based assessment and reporting (SBAR), also referred to as standards-based grading and other names, is a system for tracking student learning in a course and assigning a grade. SBAR replaces traditional grading systems by eschewing points-based assignments and evaluations. Instead, students are assessed over specific learning objectives called standards. SBAR has several advantages including: emphasis on topic mastery, development of intrinsic motivation for learning, and simplifying the grading process. I have implemented SBAR in an introductory acoustics course for music technology, sonography, and general education students. In order to change from a traditional grading system to SBAR several steps were taken. Standards were developed, assessments were written, and course policies were drafted. I will discuss the system as implemented, some of the challenges faced, and suggest ways in which the acoustics education community might provide support for others wanting to implement SBAR in their courses.

Characterization and design of sound absorber materials

Sound absorbing materials are widely used to mitigate noise in indoor environments. Foams and fiberglass are commonly used for passive noise control in the automotive, aerospace industries and for architectural design. The physics of sound absorption in porous materials is not typically included in introductory acoustics courses. However, characterization and design of sound absorbing materials and modeling of their properties can be valuable for students interested in applied acoustics. In this laboratory-oriented course at the Catholic University of America, we cover design of multilayered sound absorbers and experimental procedures for testing such materials. These include an introduction to data acquisition using LabVIEW and post-processing (with Matlab) of recorded sound as well as microphone calibration, and measurement of sound pressure level, and the frequency response function of a speaker. The second part of the course focuses on room acoustics, acoustic properties of materials, impedance tube measurements, modeling of sound propagation in porous media, and design of sound absorbers. We validate the Zwikker and Kosten model using a sample with straight cylindrical pores and apply the Delany-Bazley model to predict acoustic behavior of fibrous materials. Finally, multilayered materials are designed using the impedance translation theorem and tested with impedance tube measurements.

Impedance tube experiments as a tool to teach acoustics of porous media

As a practical matter, sound propagation in many everyday situations includes interactions with porous materials. Such materials include textiles, foams, gravel, grass-covered ground, asphalt, and trees. Modeling sound propagation in complex environments, such as passenger cabins or urban spaces, with porous materials like these is essential to understanding realistic acoustics problems. The theory behind the sound absorption in porous material is not typically included in introductory acoustics courses. This is, at least in part, attributable to the mathematical complexity of the topic. Despite this barrier, acoustic properties of porous material can be easily introduced to typical undergraduate students using simple experiments to demonstrate the acoustic effects of different materials. This presentation describes acoustic property measurements of rigid-frame porous material with straight cylindrical pores as well as foam and soil included in an “Introduction to Acoustics” class at the Catholic University of America. The apparatus is composed of a LabVIEW measurement interface, a pair of microphones, and a simple aluminum impedance tube. The modular design allows students to adapt the software or hardware for other experiments. These hands-on experiences are intended to impart a conceptual understanding of the theory of sound absorption and the acoustic performance of sound absorbing (porous) media.

Preparing University of Mississippi graduate students for careers in acoustics

The acoustics program at the University of Mississippi originated in the Physics Department and is still closely associated with physics. The physics department requires all students teach two semesters of laboratory under the supervision of a laboratory physicist. The required physics curriculum is extensive so that the acoustics students only receive two semesters of acoustics courses. This leads to careful course design so that our students are broadly literate in acoustics. The necessary compression of class work means that speaking and writing skills are taught to the student by their research advisor in preparing conference talks, written papers, and dissertations.

Navigating and developing acoustics research and curriculum within the Georgia Tech Center for Music Technology

Acoustics at the Georgia Institute of Technology has primarily been based within mechanical engineering with various other faculty spread throughout the university. Within the last decade, the School of Music has developed an internationally recognized graduate degree program and research center in music technology. Since winning the Student Paper Award, my professional career has started in a unique faculty position within the School of Music at Georgia Tech, where my responsibilities are split between being an ensemble/choral conductor and an active member of the Center for Music Technology. One of the recent challenges is the development of an innovative undergraduate curriculum model that fuses music fundamentals, music technology, general musicianship, and engineering/computer science. At the graduate level, new coursework I have created has included a musical acoustics course for music technologists and a historical acoustics and modeling course. Additionally, developing a research track of acoustics within the confines of music technology has allowed my research to morph into musically related areas that my graduate research did not allow. Areas of current research include historical architectural acoustics, active temperament, synthesis, and noise control.

Using acoustics and vibrations to teach experimental concepts and technical communications

This work describes an experience-based conceptual course in vibrations and acoustics. This one-hour course is designed with the goal of framing general experimental issues, interpreting experimental results, and developing technical communication skills in engineering by way of acoustics and vibrations experiments. Like other laboratory experiences, the goal is to support the skill of making the connection between experimental results and the physical system. Unlike other courses offered at East Carolina University and The Catholic University of America, the primary learning objectives are those connections and technical communication skills rather than the acoustics and vibrations content. Experimental issues explored include error, repeatability, linearity, uncertainty, and general experimental design. This particular set of acoustics and vibrations experiments is well suited to this purpose because they do not require extensive laboratory infrastructure, they are inherently safe, and they use commonplace tools. These tools include a speaker, microphone, and accelerometer, which the students already have as part of their laptop and/or smartphone. These tools, along with a copy of MATLAB, provide the opportunity to perform a wide array of experiments, which can illustrate sophisticated concepts using these basic, familiar items.

Reminiscences on Laymon Miller's remarkable twenty seven year consulting career at Bolt Beranek and Newman in Cambridge

Laymon Miller joined the noise control engineering consulting staff of Bolt Beranek and Newman (BBN) on August 1, 1954, bringing an impressive record of experience in acoustics from Harvard University's top secret Underwater Sound Lab (HUSL) during WWll followed by ten years as head of the acoustics section at Penn State's Ordinance Research Lab (ORL). Laymon provided invaluable mentoring for many new BBN consulting staff members like this author whose only experience in acoustics were introductory courses in architectural acoustics taught by Physics Professor Richard Bolt at MIT's School of Architecture and the MIT Acoustics Lab, Laymon quickly established a reputation among BBN employees and clients alike as an outstanding teacher and contributed to BBN's unofficial title as the “third important graduate school in Cambridge.” He documented his diverse consulting career through numerous technical papers and articles, through technical brochures he prepared for clients like the US Army Corps of Engineers,manufactures like the Baltimore Air Coil Company and through reports he prepared for thousands of BBN projects on which he served as principal consultant. Laymon retired from BBN in 1981 after a remarkable 27 year career making quieter buildings, concert halls, workplaces, communities, transportation vehicles, and in general, “the world a better place.”

Use of Multimedia Case Studies for Teaching Acoustics

Use of Multimedia Case Studies for Teaching Acoustics Pramod Rajan, P. K. Raju, Chetan S. Sankar, A. Ramachandraiah Abstract Faculty members teaching acoustic courses feel that there is a strong need to bridge the gap between theory and practice. Engineering acoustic course assignments tend to focus on oversimplified representations of acoustic problems that provide a good understanding of the concepts involved, but do not expose the students to real-world issues. This paper demonstrates the use of a multimedia case study in teaching auditoria acoustic concepts via a global real-world problem. It also discusses the design and development of the case study and presents details of the classroom implementation and evaluation aspects. The classroom implementation of this case study helped improve students’ higher-order cognitive, team-working, and problem-solving skills. In addition, students also reported the case study methodology to be a beneficial learning experience. Full Text: PDF DOI: 10.15640/jea.v3n2a19

Graduate acoustics education in the Cockrell School of Engineering at The University of Texas at Austin

While graduate study in acoustics takes place in several colleges and schools at The University of Texas at Austin (UT Austin), including Communication, Fine Arts, Geosciences, and Natural Sciences, this poster focuses on the acoustics program in Engineering. The core of this program resides in the Departments of Mechanical Engineering (ME) and Electrical and Computer Engineering (ECE). Acoustics faculty in each department supervise graduate students in both departments. One undergraduate and seven graduate acoustics courses are cross-listed in ME and ECE. Instructors for these courses include staff at Applied Research Laboratories at UT Austin, where many of the graduate students have research assistantships. The undergraduate course, taught every fall, begins with basic physical acoustics and proceeds to draw examples from different areas of engineering acoustics. Three of the graduate courses are taught every year: a two-course sequence on physical acoustics, and a transducers course. The remaining four graduate acoustics courses, taught in alternate years, are on nonlinear acoustics, underwater acoustics, ultrasonics, and architectural acoustics. An acoustics seminar is held most Fridays during the long semesters, averaging over ten per semester since 1984. The ME and ECE departments both offer Ph.D. qualifying exams in acoustics.

Underwater acoustics education at the University of Texas at Austin

The University of Texas at Austin has supported education and research in acoustics since the 1930s. The Cockrell School of Engineering currently offers a wide range of graduate courses and two undergraduate courses in acoustics, not counting the many courses in hearing, speech, seismology, and other areas of acoustics at the university. An important adjunct to the academic program in acoustics has been the Applied Research Laboratories (ARL). Spun off in 1945 from the WW II Harvard Underwater Sound Laboratory (1941–1949) and founded as the Defense Research Laboratory, ARL is one of five University Affiliated Research Centers formally recognized by the US Navy for their prominence in underwater acoustics research and development. ARL is an integral part of UT Austin, and this symbiotic combination of graduate and undergraduate courses, and laboratory and field work, provides one of the leading underwater acoustics education programs in the nation. In this talk, the underwater acoustics education program will be described with special emphasis on the underwater acoustics course and its place in the larger acoustics program. Statistics on education, funding, and placement of graduate students in the program will also be presented.

Underwater acoustics education in Harbin Engineering University

College of Underwater Acoustic Engineering in Harbin Engineering University is the earliest institution engaging in underwater acoustics education in Chinese universities, which has complete types of high education training levels and subject directions. There are 124 teachers in the college engaging in underwater acoustics research, of which there are 30 professors and 36 associate professors. The developments of underwater acoustic transducer technology, underwater positioning and navigation technology, underwater target detecting technology, underwater acoustic communication technique, multi-beam echo sounding technique, and high resolution image sonar technique new theory and technology of underwater acoustic reach the leading level in China. Every year, the college attracts more than 200 excellent students whose entrance examination marks is 80 points higher than the key fraction stroke. There are three education program levels in this specialty (undergraduate-level, graduate-level, and Ph.D.-level), and students may study underwater acoustics within any of our three programs, besides which, the college has special education programs for foreign students. Graduate employments are underwater acoustic institution, electronic institution, communication company, and IT enterprise. In this paper, descriptions of underwater acoustics education programs, curriculum systems, and teaching contents of acoustics courses will be introduced.

Graduate study in Architectural Acoustics within the Durham School at the University of Nebraska—Lincoln

Persons interested in pursuing graduate study in architectural acoustics are encouraged to consider joining the Architectural Engineering Program within the Durham School of Architectural Engineering and Construction at the University of Nebraska—Lincoln (UNL). Among the 21 ABET-accredited Architectural Engineering (AE) programs across the United States, the Durham School’s program is one of the few that offers graduate engineering degree programs (MAE, MS, and PhD) and one of only two that offers an area of concentration in architectural acoustics. Acoustics students in the Durham School benefit both from the multidisciplinary environment in an AE program and from our particularly strong ties to the building industry, since three of the largest architectural engineering companies in the United States are headquartered in Omaha, Nebraska. Descriptions will be given on the graduate-level acoustics courses, newly renovated acoustic lab facilities, the research interests and achievements of our acoustics faculty and students, and where our graduates are to date. Our group is also active in extracurricular activities, particularly through the University of Nebraska Acoustical Society of America Student Chapter. More information on the “Nebraska Acoustics Group” at the Durham School may be found online at http://nebraskaacousticsgroup.org/.

Resource Letter APPO-1: Acoustics for Physics Pedagogy and Outreach

This Resource Letter provides a guide to the use of acoustics in physics pedagogy, whether in stand-alone courses, or as examples, analogies, or demonstrations in other contexts. Included are the principal journals and conference proceedings in the field, references to descriptions of existing acoustics courses, textbooks at different levels, and myriad online resources appropriate for courses at both the introductory and advanced undergraduate levels and for outreach. Also provided are topic-specific references that are divided into source, resonance, and traveling-wave phenomena. Because of the ability of sound to bridge the gap between mathematical understanding and everyday human experience, acoustical examples and demonstrations may deepen understanding of physical phenomena at all levels.

Amar Gopal Bose

Amar Gopal Bose

Kenneth McKechnie Eldred—A distinguished noise control engineer I

Elected in mid-career in 1975 to the U.S. National Academy of Engineering (NAE) “For outstanding accomplishments in noise and vibration control of air, space, and transportation vehicles and in delineating acceptable noise environments for people.” His NAE peers recognized him “...as one of the five best noise and vibration control engineers in the country.” Ken's first job after graduating from M.I.T. in 1950 with studies of advanced courses in acoustics was as head of the Boston Naval Shipyard's lab working on the reduction of the noise and vibrations of submarine auxiliary equipment. In 1953 on active duty in the U.S. Air Force, he became Chief of the Bio-Acoustics Branch, Wright Air Development Center. In 1957, he moved to California for a career with Western Electro-Acoustic Laboratory and Wyle Laboratories prior to joining Bolt Beranek and Newman. This paper is primarily devoted to his activities in support of INCE/USA, his role in the passage of the Noise Control Act of 1972, and his activities in connection with the Office of Noise Abatement and Control in the U.S. Environmental Protection Agency.

Using Python to teach mathematics, physics, and acoustics

Advanced technical courses often suffer from a lack of interactive materials. Common tools to remedy this deficiency include MATLAB and Mathematica, both of which can be prohibitively expensive to obtain outside of the university environment. Python is a scripted language that is easy to read and use and is rapidly emerging as a lingua franca for scientific computing due to the flexibility and facility of the language, the large and active community, and the large number of high quality scientific libraries that are available in Python. Python provides a free and open source tool to develop classroom materials that students can modify and extend. We discuss the use of Python in teaching advanced topics in mathematics, physics, and acoustics. Examples are drawn from courses in acoustics, mechanics, and mathematical and computational physics

Demonstrations and laboratory experiments in a senior level acoustics course

The Physics Department at the U.S. Naval Academy has a senior level four credit course (SP436) in acoustics (called “Acoustics”) that features a well-equipped laboratory including an anechoic chamber. The course is populated by Physics Majors along with a few Engineering Majors at times. This presentation will show how Mathematica 9 is used in the laboratory portion of the course to enhance lecture topics and student computational assignments. It is “hands-on” which helps motivate and enhance learning. Students learn the fundamentals of Mathematica as part of the laboratory experience. Tasks after data collection, including analysis and write-up, are done with this software. Workstations include laptop personal computers, spectrum analyzers, oscilloscopes, laser Doppler vibrometers, and various accelerometers, mics, hydrophones, and ultrasonic transducers. A demonstration of standing waves in a cylindrical cavity will be presented as a representation of some of our featured lab experiments—including: Helmholtz resonators, linear and nonlinear vibration of a circular membrane, or circular elastic plate, flexural waves on a thin bar, Chladni plates, the hanging oscillating chain, spectral analysis (Fourier series, Fourier integral), sound speed vs. temperature and salinity, acoustic landmine detection, moving coil loud speaker, waves on strings, transmitting arrays, and wave guide studies.

Resources for teaching near-field acoustical holography in advanced acoustics courses

The principles of planar near-field acoustical holography (NAH) can be used to motivate discussion of, or illustrate, physics of sound radiation or topics in signal processing. These include separable geometries, the Helmholtz equation, spatial Fourier transforms and the wavenumber domain, superposition of waves, the relationship between pressure and particle velocity, near and far fields, the radiation circle and evanescence, filtering, and signal-to-noise ratio. This paper describes the incorporation of NAH as part of a graduate-course unit on structural acoustics. Resources discussed, and which will be made available to educators, include a basic NAH processing script and example data collected by students using an automated positioning system in Brigham Young University's fully anechoic chamber.