Physics & Astronomy

There are several physical facilities available on campus at BYU for acoustics and structural dynamics research.  There is an anechoic chamber that simulates free-field radiation conditions.  The chamber has working dimensions of 14'6" X 14'10" X 29', and is anechoic down to approximately 70 Hz.  In addition, a measurement boom in the chamber has been built that allows the acquisition of global radiation data from a source.  This boom is a semi-circular boom with thirteen microphones mounted on it.  The boom is computer controlled and has a stepper motor which allows the boom to be rotated to map out the acoustic field over an entire hemisphere.  This provides the capability of measuring both the directivity function and the radiated acoustic power associated with a source.

In addition to the anechoic chamber, there is an additional chamber that is smaller in size, and has variable acoustic properties, such that various acoustic conditions can be established in the enclosure.  Furthermore, two new reverberation chambers have recently been constructed (210 cubic meters and 70 cubic meters) is underway.  These rooms are adjacent to each other and are acoustically coupled to allow transmission loss testing.

There are a number of resources available for performing the numerical analysis involved with projects.  The software packages SysNoise, VitrualLab, IDEAS, CATT, EASE/EARS, Fluent, and FIDAP are available.  Other fairly standard software packages, such as MATLAB and LabView are also available.  The research group has direct access to several PCs, and SGI workstations.  Furthermore, BYU has one of the largest university owned supercomputing facilities, being ranked in the top five nationally.  These supercomputers can run the SysNoise, IDEAS, and Fluent packages when needed, to take advantage of the parallel processing capabilities and faster computation times.

General purpose hardware, such as microphones, loudspeakers, signal filters, and amplifiers are also available to assist in the research.  Three Hewlett-Packard/Agilent dynamic signal analyzers (48 channels, 4 channels, and 2 channels) are available for general  purpose measurements as well as a Bruel and Kjaer Pulse system (12 channels). Two specialty analyzers (TEF 20 and MLSSA) are available for transducer and room acoustics measurements.  A computer-controlled turntable may be used to rotate booms, sources, sensors, or arrays within chambers if required.  An acoustic intensity probe is available for determining acoustic intensity in a sound field.  General purpose hardware such as microphones, accelerometers, loudspeakers, shakers, and so forth are also available.  A scanning laser Doppler vibrometer (SLDV) is available for nonintrusive structural vibration measurements.

Chambers

• Large anechoic chamber (14'6" x 14'10" x 29' working dimensions), anechoic down to approximately 70 Hz.
• Small hemi-anechoic chamber.
• Large 210 m³ reverberation chamber
• Small 65 m³ reverberation chamber

Analyzers

• Data Physics SignalCalc 620 48 channel dynamic signal analyzer based on the Agilent VXI platform.
• Hewlett-Packard HP35670A 4 channel dynamic signal analyzer.
• Hewlett-Packard HP35670A 2 channel dynamic signal analyzer.
• Bruel and Kjaer 12 channel Pulse system.
• Larson-Davis 2900B real-time analyzer.
• DRA MLSSA analyzer.
• Gold Line TEF 20 analyzer.
• SIA SMAART PC-based analyzer.
• Two Larson-Davis 824-2541 type 1 sound level meter/real-time analyzers.

Transducers

• Over 40 type 1 precision microphones with preamps and power supplies (Larson Davis, Bruel and Kjaer).
• Various directional condenser and dynamic microphones.
• Larson Davis intensity probe.
• Various energy density probe prototypes.
• Knowles KEMAR binaural dummy head.
• Various PCB accelerometers.
• PCB impact hammer kit.
• Wide selection of powered and unpowered full-range loudspeakers, subwoofers, etc.
• Various LDS shakers.
• Studio-grade headphones.
• Broad selection of "omnidirectional" platonic polyhedral loudspeakers (PPLs), e.g., tetrahedron, hexahedron, octahedron, dodecahedron, and icosahedron sources.

Electronics

• Various instrumentation-grade signal filters.
• Various instrumentation-grade signal amplifiers.
• Computer-controlled mixers with on-board DSPs.
• Various ICP power supplies and signal conditioners.
• Various power amplifiers.
• Various digital signal processing (DSP) system boards with associated multichannel I/O and software.
• Various analog and digitizing oscilloscopes.
• Other miscellaneous devices (arbitrary waveform generators, frequency counters, multimeters, etc).

Computers

• Various desktop PC’s and PC workstations.
• Various laptop PC’s.
• IBM SP-2 supercomputer.
• SGI Origin 3000 supercomputer.
• Two SGI Origin 2000 supercomputers

Specialized Software

• Fundamental mathematics packages (MATLAB, Maple, Mathcad, etc.).
• LMS SYSNOISE (acoustic finite element method and boundary element method).
• LMS VirtualLab (Acoustic modeling software including finite element method and boundary element method)
• ADA EASE/EARS (Acoustic ray tracing method, image source method, auralization).
• CATT Acoustics (Acoustic ray tracing method, image source method, auralization).
• Various PC-based data recording, editing, analysis and manipulation programs.

Other Devices

• Scanning Laser Doppler Vibrometer
• Computer-controlled turntable.
• Computer-controlled semicircular boom.
• Source directivity measurement arrays.
• Impedance tubes.
• Cartesian axis directional microphone positioning system.
• Spherical coordinate laser positioning system
• Optically based vibration measurement systems (Moire and electro-optic holography).