Areas of Acoustics

With sound touching our lives in so many different ways, it is no surprise that acoustics, the study of sound and vibration, addresses a great variety of issues. The areas of study can be grouped in different ways, though most groupings are similar to the definition of technical committees in the Acoustical Society of America (see Appendix A of the ASA Rules). Using the ASA approach as a starting point, we have the following areas of acoustics:

• Acoustical Oceanography
• Animal Bioacoustics
• Architectural Acoustics
• Biomedical Acoustics
• Engineering Acoustics
• Musical Acoustics
• Noise
• Physical Acoustics
• Psychological and Physiological Acoustics
• Signal Processing in Acoustics
• Speech Communication
• Structural Acoustics and Vibration
• Underwater Acoustics

Acoustical Oceanography

Concerned with the use of acoustical techniques to measure and understand physical, biological, geological, and chemical parameters and processes of the sea.

Animal Bioacoustics

Concerned with:

1. Animal communication, biosonar, and associated behavior
2. Sound production anatomy and neurophysiology of animals
3. Auditory capacities and mechanisms, anatomy, and neurophysiology of animals
4. Acoustic methods for use in population assessment, identification, and behavior
5. Acoustic ecology and effects of sound on animals
6. Instrumentation, algorithms and analysis methods for animal acoustics

Architectural Acoustics

Encompasses the following areas of interest as applied to sound in and around buildings:

1. Room finish treatments, surface shaping, volumes, and geometries
2. Airborne and structureborne sound isolation and noise control
3. Noise and vibration control of building systems
4. Electroacoustic and media systems
5. Perception and psychoacoustics

Biomedical Acoustics

Concerned with the study of the interactions of acoustic waves with biological materials, including cells, tissues, organ systems and entire organisms. Relevant areas of interest include but are not limited to:

1. Diagnostic and therapeutic applications of acoustics in medicine
2. Biological effects of exposure to mechanical vibration and acoustic waves
3. Acoustic propagation in biological materials
4. Instrumentation
5. Ultrasound field calibration, exposimetry and dosimetry
6. Ultrasound contrast agents
7. Medical image and signal processing
8. Characterization and processing of biological materials
9. Physiological measurements

Engineering Acoustics

Encompasses the theory and practice of creating tools for investigating acoustical phenomena and applying knowledge of acoustics to practical utility. This includes:

1. The design and modeling of acoustical and vibrational transducers, arrays, and transduction systems in all media and frequency ranges
2. Instrumentation, metrology, and calibration
3. Measurement and computational techniques as they relate to acoustical phenomena and their utility
4. The engineering of materials and devices

Musical Acoustics

Concerned with the application of science and technology to the field of music. Of particular current interest are the following topics:

1. Physics of musical sound production
2. Music perception and cognition
3. Analysis and synthesis of musical sounds and compositions

Noise

To increase and diffuse knowledge of noise generation and propagation, passive and active noise control, perception and the effects of noise, and the management of exposure to noise. Activities embrace the practical and theoretical aspects of noise in all areas of acoustics. Specific topics of interest include:

1. Measurement, prediction, and modeling of noise and vibration
2. Soundscapes, urban and natural
3. Product sound quality
4. Classroom acoustics
5. Quiet system design
6. Occupational and recreational exposure to noise
7. Speech privacy
8. Legal aspects of noise
9. Codes and standards

Physical Acoustics

Concerned with fundamental acoustic wave phenomena from infrasonic to ultrasonic frequencies. Theoretical, computational, and experimental approaches are used. Topics being investigated include:

1. Use of acoustics in probing the physical properties of materials and other systems with relevance to physics and geophysics
2. Sound and vibrations in fluid-filled media, including porous media
3. Thermoacoustics
4. Propagation of sound in planetary atmospheres
5. Nonlinear acoustics and shock waves in gases, liquids, and solids
6. Cavitation phenomena in physical and biological media
7. Interaction of sound with light and other forms of radiation
8. Attenuative processes and dispersion of sound

Psychological and Physiological Acoustics

concerned with the investigation and the dissemination of information about psychological and physiological responses to sound in humans and other species. Areas of interest include, but are not limited to:

1. Perception and perceptual organization of simple and complex sounds, including speech
2. Anatomy and function of the auditory pathways, including all physical and biological responses to auditory stimulation
3. Hearing disorders, hearing loss, and auditory prostheses
4. Vibrotactile and vestibular sensation, and the interaction of hearing with other sensory modalities
5. Developmental, aging, learning and plasticity effects in auditory function
6. Theories and models of auditory processes

Signal Processing in Acoustics

Signal processing is the acquisition and generation of signals and the extraction of information from signals. It is an important tool in all areas of acoustics. Using signal processing algorithms, acousticians are able to extract signals from noise, to compress information for more efficient storage or transmission, to perform active noise cancellation, etc. The continuing technological advances in high-speed processing and memory will open more avenues of investigation in acoustics.

Speech Communication

Concerned with the study of the production, transmission, and perception of speech, including the following:

1. Speech production: physiology, mechanics, and acoustics of speech and voice production; models of speech production; first-language and second-language speech production
2. Acoustic phonetics, including segmental and suprasegmental aspects of speech
3. Speech perception: physiological and psychological aspects of speech perception; voice quality perception; models of speech perception; first-language, cross-language, and second-language speech perception
4. Speech acquisition: acquisition of speech production and perception; first-language and second-language speech acquisition; models of speech acquisition
5. Speech and hearing disorders: effects of speech production disorders on the articulation, acoustics, and perception of speech; effects of hearing impairment on speech perception and production; effects of aided hearing or speech (e.g., hearing aids, cochlear implants, electrolarynx) on speech perception and production
6. Neuroscience of speech production and perception
7. Speech intelligibility: perception and intelligibility of accented, disordered, and synthetic speech, and of speech degraded by noise or transmission channel; production and perception of speech in acoustically adverse environments
8. Communicative aspects of singing: production and perception of phonetic or emotional content in song
9. Speaker classification and speaker identity: articulatory, acoustic, and perceptual properties of speech linked to a speaker’s sex, gender, age, and emotional state; sociophonetics; speaker, language, and dialect recognition by humans and machines; forensic voice comparison
10. Audiovisual and other multimodal speech perception
11. Speech processing and speech technology: signal processing of speech; speech synthesis; automatic speech recognition

Structural Acoustics and Vibration

Structural Acoustics is the study of the interaction of vibrating structures with adjacent fluid along with the accompanying radiated or scattered sound. Structural Vibrations is the study of the linear and nonlinear vibration of structural components and waves in solid media. Applications of research outlined in the technical areas of SAV are found in a number of compelling and important applications that affect our health, safety, as well as the effectiveness of the products we engineer. Topics of interest include:

1. Prediction of structural acoustics and vibration using analytic techniques, numerical approaches (e.g., finite element methods, boundary element methods, and statistical energy analysis), and benchmark comparisons of predictions to experiments
2. Inverse methods (e.g., estimating structural response from the measured sound field and the radiated/scattered field from structural measurements) including nearfield acoustical holography (NAH) /Statistically optimized NAH (SONAH) and finite element model updating (using measurements to update the FE model)
3. Control of structural acoustics and vibration using active control, passive control with optimization, treatments, and material selection, design methodology for vibration control, smart structural methods
4. Advanced instrumentation for structural acoustics and vibration, including microphone/hydrophones and arrays, optical (e.g., laser Doppler velocimetry), accelerometers, geophones, and structural intensity sensors, and power harvesting
5. Constitutive modeling and the influence of the material behavior on the response (e.g., piezoelectricity, friction, damping and viscoelasticity)
6. Waves in solid media

Underwater Acoustics

Sound-wave phenomena in the ocean and seabed, with primary emphasis on the following topics:

1. Propagation phenomena: steady-state and transient solutions of the wave equation, including boundary effects, and seismoacoustics
2. Scattering and reverberation: characterization and quantification
3. Ambient noise: noise sources, spectra, directionality, and spatial/temporal fluctuations
4. Signal processing and sonar algorithms, with emphasis on the detection of signals in noise and statistical analysis