ISSN:0001-4966    

DOI:10.1121/1.1915722

出版商:Acoustical Society of America    

年代:1935

数据来源: AIP

摘要:

In a recent paper by Mr. Parkinson and myself (Loudness and Intensity Relations, J.A.S.A. 3, 511–534 (1932)), a series of experiments were described concerning the comparison of the loudness of one tone with a fixed tone of the same frequency characteristics. The present series of experiments are similar except being confined mostly to low tones between 60 and 500 cycles per second. Present experiments carried out with the same frequencies and under similar experimental conditions as the former series yielded similar results. In the very low frequencies, the value ofnobtained for the equation used in the former series is larger, which means that the decibel intervals for corresponding loudnesses are smaller. Certain experimental factors, however, have appeared in the present experiments that did not appear in the previously published data due, in part apparently, to differences in experimental technique. We did not find any noticeable effects in the very few experiments tried in the previous series on interchanging the order of the energy decreases. Interchanging the order of energy changes has been tried in the present series.

ISSN:0001-4966    

DOI:10.1121/1.1915728

出版商:Acoustical Society of America    

年代:1935

数据来源: AIP

摘要:

Output intensity measurements and harmonic analyses were made on the open strings of a series of twenty‐one violins ranging in price from $25 to $10,000 each. To secure standardized conditions, a mechanical bowing device was used, and the pressure, speed, and relative position of the bow maintained constant. A crystal harmonic analyzer, operating synchronously with an automatic level recorder, furnished a graphical record of the desired tone structures. The measured responses, tone centers, and tone structure factors were plotted against the retail prices of the violins and correlations found to exist.

ISSN:0001-4966    

DOI:10.1121/1.1915730

出版商:Acoustical Society of America    

年代:1935

数据来源: AIP

摘要:

Several investigators have shown recently that if the changes in the internal energy of a gas take place so slowly that they cannot follow the adiabatic changes which result when a sound wave passes through the gas, sound dispersion and anomalous absorption of observable magnitudes occur. Experimentally, it is found that the absorption in the air, for example, not only depends upon temperature and humidity in a characteristic manner, unsuspected by classical theory, but at frequencies above 1000 cycles is so great as to require consideration in such technical problems as architectural acoustics and sound signaling. The findings are in good agreement with the new theory. The presence of small impurities (less than one percent) in gases may change the speed of sound at certain frequencies as much as several percent: and the absorption coefficient as much as several hundred percent. Absorption measurements for frequencies between 1000 and 40,000 cycles inO2containing small impurities ofH2, He,H2O, H2S, NH3, CO,CO2, O3, C2H2, or one of many other hydrocarbons throw light on the nature of molecular collisions. A new device is thus available for studies in molecular physics, and acoustics has become a potent ally of the quantum theory.

ISSN:0001-4966    

DOI:10.1121/1.1915736

出版商:Acoustical Society of America    

年代:1935

数据来源: AIP