There is no question that this monograph provides much excellent critical analysis of data dealing with many facets of the effects of noise, and can therefore serve as an introduction and bibliographic source reference for any contemplated more thorough study of such facets. However, the coverage is far from complete: Besides the exclusion of literature in foreign languages, and of most animal studies, topics mentioned only briefly, if at all, include auditory effects other than loss of pure-tone sensitivity (e.g., changes in differential thresholds, tinnitus, etc.), the physiological substrate of even pure-tone loss, individual differences in susceptibility to damage, and the whole field of hearing protectors. In addition, the level of critical insight is not uniform, nor is the accuracy of the presentation: All too often experimental parameters are misstated, graphs and equations are reproduced without enough accompanying information to permit them to be understood, or experiments are misinterpreted. Indeed, some studies are ignored whose results challenge the validity of assumptions that Kryter makes in order to support his idiosyncratic recommendations for noise regulations. So although this book will be an indispensible asset to any future investigator concerned with one of the effects of noise on man, it is only a starting point, not a final authority: It will still be necessary to study original sources in order to achieve a balanced view of the state of knowledge about the noise effect under consideration.

The behavior of the cavity resonance in open tubes of barium titanate and lead zirconate titanate ceramic immersed in water has been studied both experimentally and theoretically for a range of length-to-radius ratios (h/a). Particular emphasis is given to tubes of small h/a where the cavity-resonant frequency is nearthe ring-resonant frequency of the tube, and close coupling is observed between the two modes. A coaxial line array of such elements, which has been built and tested, exhibits a high efficiency over a wide frequency band. Since no pressure release is used in its construction, this transducer is promising as a lightweight, high-power sound source for operation at great depths in the ocean.

An experimental study has been carried out to determine the natural frequencies of vibration of solid, isotropic, elastic cylinders with free boundaries. Solid aluminum and steel cylinders having height-to-radius ratios (h/a) between 0.2 and 3.3 have been studied. Twenty of the graver modes were excited by means of a barium titanate driver loosely coupled to the metal cylinders. Six modes of circumferential order zero, seven modes of order unity, four modes of order two, and three modes of order three were studied in the range of dimensionless frequency parameter ωa/c from zero to 2.6. Sand patterns and a small vibration probe were used to determine the form of the vibrations. Where possible, the frequencies are compared with the results of existing theory.

No abstract

A reciprocity system has been developed for the absolute acoustic calibration of small hydrophones at hydrostatic pressures up to 15 000 psi and frequencies to 400 cps. The method involves electrical measurements on three transducers placed in a closed, stiff-walled "coupler" vessel and a measurement of the static acoustic compliance of the coupler. LIST OF SYMBOLSThe three transducers used in the coupler-reciprocity measurement are denoted by the symbols { 1 }, { 2}, and {3}; associated quantities are represented by s•nbols with subscripts 1, 2, and 3, respectively. Following is a list of symbols given without the subscripts: Mo [e/pol open-circuit receiving sensitivity of a transducer.In this paper, all of the above quantities are in mks units.