Gary W. Siebein

Chronological analysis of architectural and acoustical indices in music performance halls

This study aims to identify the changes in architectural and acoustical indices in halls for music performance built in the 18th through the 20th Centuries. Seventy-one halls are classified in five specific periods from the Classical Period (1751-1820) to the Contemporary Period (1981-2000) based on chronology in music and architectural acoustics. Architectural indices such as room shape, seating capacity, room volume, balcony configuration, and the like as well as acoustical indices such as RT, EDT, G, C80, IACC, and the like for the halls found in the literature are chronologically tabulated and statistically analyzed to identify trends and relationships in architectural and acoustical design for each of the historical periods identified. Some indices appear correlated with each other.

Case study of soundscape assessment and design methods

A case study of the soundscape assessment and design process for an urban design intervention in a medium‐sized city was conducted as an investigation of acoustical assessment and design methods. A series of long‐term acoustical measurements of average sound levels in the community as well as more detailed measurements and aural recordings of specific acoustic events that comprised the ambient sounds were mapped for the community. Measurements included overall A‐weighted and octave band sound levels and calibrated audio recordings. Sound walks were conducted at various times of day to understand the dynamics of the acoustical environment and to identify issues. Focus group discussions among stakeholders and team members developed the long‐term plans for the community and determined appropriate architectural and acoustical design criteria for the project. The acoustical data were used as the basis for determining design strategies for the urban interventions including reducing, buffering, and mitigating un...

Acoustical case studies of three green buildings

Case studies of 3 green buildings with LEED certifications that required extensive acoustical retrofit work to become satisfactory work environments for their intended user groups will be used to define areas where green building design concepts and acoustical design concepts require reconciliation. Case study 1 is an office and conference center for a city environmental education agency. Large open spaces intended to collect daylight through clerestory windows provided large, reverberant volumes with few acoustic finishes that rendered them unsuitable as open office space and a conference room/auditorium. Case Study 2 describes one of the first gold LEED buildings in the southeast whose primary design concepts were so narrowly focused on thermal and lighting issues that they often worked directly against basic acoustical requirements resulting in sound levels of NC 50–55 in classrooms and faculty offices, crosstalk between classrooms and poor room acoustics. Case study 3 is an environmental education and conference center with open public areas, very high ceilings, and all reflective surfaces made from wood and other environmentally friendly materials that result in excessive loudness when the building is used by the numbers of people which it was intended to serve.

Computer model studies of RASTI values in classrooms

Computer models of classrooms were used to study the effects of room shape, furniture arrangement and interior finish materials at various background noise levels. The background noise levels used in the computer models were obtained in field measurements of actual classrooms and varied from approximately Noise Criterion (NC) 25 to NC 65. A sound source was configured to approximate the level, frequency and directionality of the normal speaking voice of a teacher in the room. RASTI, reverberation time, loudness, and early energy ratios were estimated for multiple seating locations in each room for each background noise level. RASTI was related to background noise level (NC rating), distance and room finish materials with a second order equation with a model r2 of 0.96. The background noise level had the primary effect on RASTI values in the rooms. Once a background noise level of NC 35 or less was achieved, the amount and distribution of absorbent materials in the room became important factors. Reflective...

Classroom acoustics III: Acoustical model studies of elementary school classrooms

A 1:4 scale model was constructed with a series of interchangeable wall and ceiling panels to allow a battery of acoustical tests to be conducted for a variety of classroom designs. The walls and ceiling of the room could be changed from sound absorbent to sound reflective materials quickly. Scale furniture was also constructed for the room. The walls of the model could be adjusted from approximately 7 to 10 meters in length and from 2.5 m in height to 7 m in height. Acoustical measurements of speech transmission index, reverberation time, early reverberation time, early‐to‐late energy ratios, loudness (or relative strength), and articulation index were made in a number of simulated elementary school classrooms using both a TEF analyzer and impulse spark techniques. Classrooms where field measurements were taken as described in Classroom Acoustics II were modified to attempt to improve acoustical conditions in the rooms. The location and amount of absorbent material, the location and amount of sound refle...

Subjective and objective evaluations of rooms for music

A dedicated, computer‐based analysis system was developed to perform a complete set of acoustical measurements of recent interest in full‐size rooms and in scale models of rooms. The measurements included reverberation time, early reverberation time, loudness, early to late temporal energy ratios, lateral energy fractions, interaural cross correlation, and speech transmission index among others. Measurements were made at multiple locations in ten large concert halls. Groups of listeners evaluated live music performances at three locations in each of the rooms using a seven point semantic differential rating scale. Correlation analysis and statistical modeling identified significant relationships among the qualities of the music in the room rated by the listeners with the physical measurements made in the rooms. Variations of subjective qualities were identified among the different rooms and within each of the rooms as well. The subjective qualities that contributed to overall acoustical impression were al...

Soundscape study for the improvement of neonatal intensive care units

Guidelines for healthcare spaces address day and nighttime Leq and peak levels. However, there are many complex and transient sounds that make up the overall sound levels in healthcare environments. Many of these sounds contribute to the background level, while others are transient noises and alerts to professionals who must hear them to care for their patients. Unfortunately, these noisy environments are also where the patient is placed to heal. Three different Neonatal Intensive Care Units (NICUs) built in different years in Florida were observed and categories of sounds in each were documented. Overall level vs. time measurements made over a one week time period in each NICU were compared with WHO guidelines. Spectral level measurements of individual and combined sounds are also documented in each NICU. The individual sounds were classified into necessary and unnecessary criteria that orchestrate at all times of the day by observing and documenting them. The results of this study show how changes being...

Local sonic wonders: Tectonics of measuring, modeling, and mapping aspects of soundscapes.

Soundscape theory is based on the premise that the ambient sound in an area is composed of a series of specific acoustic events that can be measured and modeled. In order to technically execute the process of measuring the specific acoustic events in a soundscape, each event must first be identified in an acoustic taxonomy and then measured in sufficient detail to allow modeling of the perceptually robust aspects of the event, so auralizations or other assessments of existing and future sounds can be made. The evaluation of site planning strategies was based on whether the sound levels at the proposed site would first comply with the noise ordinance, and second, be audible at homes when windows were open late at night at levels that might disturb sleep or be otherwise annoying. Full size simulations of sounds from entertainment establishments played into neighborhoods so people could listen to proposed sounds in their homes and yards as a method to allow citizens to participate in public hearings where ac...

Soundscape documentation of parks and natural areas.

A multi‐media method to document the distinctions among qualities of sounds with relatively similar levels in a natural, outdoor environment was developed. Simultaneous recordings of sound levels, calibrated aural recordings of .wav files of specific acoustic events, and video photography of the events were overlaid on a map of the site to document the itinerary of the observer. The multi‐media method attempted to more completely document the nature of the soundscape with its subtle changes in sources of sound, level, frequency, and time duration than typical environmental noise metrics such as Leq’s, LDN’s and other long term average sound metrics. The sound levels measured near the road are similar to those taken at locations within the park; however, the quality of sounds is very different from each other. The acoustical transition from a street edge into a dense, natural park was examined. The experiment shows how the nature of sound shifts dramatically through the site while the perceived average sou...

Background noise levels in classrooms

Field measurements of background noise levels produced by air‐conditioning systems were taken in a sample of 47 elementary school classrooms. Noise levels were grouped by air‐conditioning system type and resulting noise criterion (NC) levels. Eight computer models of classrooms were constructed with varying combinations of absorbent materials on the surfaces of the rooms. A sound source was configured to approximate the normal speaking voice of a teacher in the room. RASTI measures were estimated for six seating locations in each room for background noise levels from 0 dB to NC‐ 55 in 5‐NC point increments. RASTI values remained above 0.8 in seven of the eight rooms at NC levels of 32 and below. RASTI levels decreased to 0.50 and less in all eight rooms at levels of NC‐ 45. The one exception to this was the room constructed with a gypsum board ceiling, vinyl tile floor, and gypsum board walls. Even with no background noise, RASTI values in this room never exceeded 0.60. Background noise levels of NC 32 or...