ISSN:0001-4966    

DOI:10.1121/1.1915933

出版商:Acoustical Society of America    

年代:1938

数据来源: AIP

摘要:

The first tube considered consists of two open cylinders of different diameters joined end to end. The theoretical expression for the frequencies of standing waves in such tubes is not new, but it leads to a rather surprising result which is now tested experimentally. The second tube considered consists of two open cylinders of different diameters joined by a conical connecting tube. A theoretical expression for the frequencies of standing waves in such a tube is developed. For the one tube examined experimentally the agreement between theory and experiment is satisfactory.

ISSN:0001-4966    

DOI:10.1121/1.1902037

出版商:Acoustical Society of America    

年代:1938

数据来源: AIP

摘要:

The measurement of noise by the use of sound level meters has been accepted by the aeronautic and automotive industries. Such measurements may be of comparative value for reasonably continuous composite noise. This is particularly true when the types of noise produced by the objects under comparison are similar in nature. Under properly controlled conditions, such measurements are of value in determining the relative success of various attempts or methods of noise reduction. In attacking noise reduction from an engineering standpoint, it is generally desirable to consider the individual physical characteristics of noise. Some of these characteristics and their effect on methods of instrumentation are discussed.

ISSN:0001-4966    

DOI:10.1121/1.1902041

出版商:Acoustical Society of America    

年代:1938

数据来源: AIP

摘要:

Further measurements on the absorption of sound inCO2reveal that the nonclassical (or collision) absorption begins at about 3000 cycles and increases rapidly for higher frequencies (to 34,000 cycles). This is probably a portion of the absorption band which has its maximum at about 105cycles. The addition of small impurities, such asH2Oand various alcohols, greatly reduces the absorption in the frequency range investigated, namely that corresponding to the ascending branch of the absorption band. This is explained on the assumption that the effect of such impurities is to shorten the lifetime of the vibration of theCO2molecule, that is, the absorption maximum is shifted to higher frequencies. A similar shift of the dispersion band has been observed in the velocity measurements of Eucken, Becker, and others. Although the absorption inCO2at 8000 cycles is quite large (of the order of 2 db/ft.), the addition of a small impurity of water vapor (less than 0.5 percent) reduces the absorption to less than that for pureN2. This is consistent with the classical theory, and probably means that at such frequencies there is very little, if any, nonclassical absorption inCO2containing small impurities ofH2O. This also is the case for certain other impurities.

ISSN:0001-4966    

DOI:10.1121/1.1902049

出版商:Acoustical Society of America    

年代:1938

数据来源: AIP

摘要:

It has been shown by Lewis and Larsen that the phase and the magnitude of a subjective tone heard monaurally may differ significantly for two different observers with normal hearing. This paper deals with a study of the two ears of the same observer. Differences as well as similarities in both phase and magnitude are indicated, differences in magnitude being more common than differences in phase. Further investigation seems necessary before a satisfactory explanation of the findings can be offered.

ISSN:0001-4966    

DOI:10.1121/1.1902054

出版商:Acoustical Society of America    

年代:1938

数据来源: AIP