Measuring different acoustical properties have been the key in reducing noise and improving the sound quality from various sources. In this report, a broadband (200 Hz – 6.5 kHz) three-dimensional seven-microphone intensity probe system is developed to measure the sound intensity, and total energy density in different acoustical environments. Limitations of most commercial intensity probes in measuring the three-dimensional intensity for a broadband sound field was the main motivation in developing this probe. The finite-difference error and the phase mismatch error which are the two main errors associated with the intensity measurements are addressed in this report. As for the physical design, seven microphones were arranged in a two-concentric arrays with one microphone located at the center of the probe. The outer array is for low-frequencies (200 Hz – 1.0 kHz), and the inner one is for high-frequencies (1.0 kHz – 6.5 kHz). The screw adjustable center microphone is used for the microphone calibration, and as the reference microphone of the probe. The simultaneous calibrations of all the microphones in the probe were done in the anechoic room. Theories for the intensity and the energy densities calculations for the probe were derived from the existing four-microphone probe configuration. Reflection and diffraction effects on the intensity measurements due to the presence of the microphones, and the supporting structures were also investigated in this report. Directivity patterns of the calculated intensity showed the omnidirectional nature of the probe. The intensity, and total energy density were calculated and compared with the ideal values in the anechoic room environment. Characterization of sound fields in a reverberant enclosed space, and sound source identification are some applications that were investigated using this probe. Results of different measurements showed effectiveness of the probe as a tool to measure key acoustical properties in many practical environments. / text

The specific problems investigated involved identifying and describing the characteristics of fundamental frequency, overall intensity, and spectral content in unaccompanied and ensemble performance settings. Additionally, comparisons and descriptions of the relationships among these acoustical parameters were made. Fifteen trombonists were used as research subjects. Each subject recorded a selected musical excerpt in the following performance modes: high register unaccompanied, harmonic, and unison ensemble; and low register unaccompanied and unison ensemble. Tape recordings of these subjects were used in conjunction with certain electronic apparatus to obtain data on frequency, intensity, and spectral content. Based on these data, descriptions of these acoustical parameters and comparisons of unaccompanied and ensemble performance settings were made.

Comprehensive studies are needed to better understand the original acoustical features of historical baths in order to uncover the historical technologies that enabled the acoustical performance for which they are renowned and to ensure they retain this performance with time. In this study, acoustic performances of Seng&uuml / l Hamami and Kadi Hamami, two 15th century historical baths belonging to the Ottoman period, were examined to discover their original acoustical features and to assess their present situation by taking into consideration the recent incompatible repair work. The analyses were done by using 3D computer modeling and acoustical simulation methods supported by laboratory analyses. The results were evaluated in terms of sound absorption characteristics of historical lime-based plasters, the original acoustical features of historical Turkish baths and acoustical failures related to recent repairs. The study showed that these baths had originally well-designed acoustical features provide for a proper environment for musical performances. This success was attributed to the conscious use of historical materials having high sound absorption characteristics. It was seen that these original acoustical features had been destroyed by wrong repairs using cement-based plasters. These plasters demonstrated incompatible acoustical properties, such as less porosity and lower sound absorption coefficients. This study also helped to define acoustical specifications for such historical baths to be maintained in restoration work.