Multiple-driver dodecahedron loudspeakers are commonly used in room acoustics measurements as omnidirectional sources of sound. Yet they and other regular polyhedron loudspeakers become "multidirectional" above their omnidirectional cutoff frequencies ͑often near 1 kHz͒. Because these cutoff frequencies normally fall within common measurement bandwidths, one might question whether anything is really extraordinary about the dodecahedron loudspeaker or whether another regular polyhedron geometry would actually produce better average omnidirectionality over these bandwidths. This paper explores these questions through measured data, analysis, and comparison of frequency-dependent directivities of several regular polyhedron loudspeaker prototypes. It provides insights into their radiation properties and introduces an alternative method of quantifying omnidirectionality: the area-weighted spatial standard deviation of radiated levels over a free-field measurement sphere. It compares this method to the ISO 3382:1997͑E͒ standard method, revealing certain discrepancies between the two approaches. A dodecahedron loudspeaker is shown to produce a relatively high cutoff frequency and reasonable radiation uniformity over measurement bandwidths. However, it does not necessarily excel as a better omnidirectional source than other regular polyhedron loudspeakers. A tetrahedron loudspeaker with an equal midradius provides the best average radiation uniformity over a 4 kHz bandwidth, even though it exhibits the lowest cutoff frequency.

An acoustical survey of the Salt Lake Mormon Tabernacle has been performed to assess the behavior of the hall in its current state. The tabernacle is a well-known historical building with a large elongated dome ceiling. This paper discusses the measurements used to characterize the hall. Several parameters derived from omnidirectional, directional, and binaural impulse response measurements are presented. Color maps of the parameters over audience seating areas reveal their spatial variations. These maps and the statistical properties of the parameters aid in clarifying the acoustical characteristics and anomalies of the hall.

The Salt Lake Tabernacle and LDS Conference Center have interesting acoustical properties. Due to the elongated domed ceiling of the Tabernacle, there are audible focusing effects throughout the hall. In order to characterize the Tabernacle’s unique acoustics prior to its seismic renovation, the acoustical properties of the hall were investigated through impulse response measurements and computer modeling. This paper will show how the measurements and model were used to see the focusing effects in the Tabernacle. The acoustics of the LDS Conference Center have also been extensively measured. This paper will show various methods that were used to investigate the sound focusing effects that were audible in the Conference Center.

Current and historical properties of the Salt Lake Tabernacle have been investigated to characterize its unique acoustics. This characterization will be used to help maintain the current acoustical conditions after a seismic renovation. This paper discusses computer models developed for this purpose and impulse response measurements taken to quantify the acoustics in their current state. It also explores spatial variation of room acoustic parameters derived from the models and measurements.

Auralizations in computer modeling are affected by many different variables, such as absorption coefficients, scattering coefficients, and the complexity of the model. However, scattering coefficients are often determined by the best guess of the consultant. In order to isolate the changes due to the scattering coefficient for comparison with measured data, a simple rectilinear room was measured and modeled. This paper will show how changing the architectural surface and audience scattering coefficients affects the auralizations for this room. For comparison, the effects of changing these same coefficients in a larger venue will also be presented.