摘要:

The results are given for a series of phonetic evaluation tests which were made by means of synthetically produced vowel sounds. By employing synthetically produced sounds, a number of the significant parameters could be varied in an independent and systematic manner without encountering the uncertainties and limitations of the human speech mechanism. The types of parameter changes which were investigated by this means were those of fundamental frequency or pitch, formant frequency and amplitude, and, finally, the number of formants important to a sound. The results of the tests indicate that all of these parameters are important in the evaluation of the sound. In particular, there is a shift in the phonetic evaluation which can be attributed to pitch alone.

ISSN:0001-4966    

DOI:10.1121/1.1906983

出版商:Acoustical Society of America    

年代:1953

数据来源: AIP

摘要:

Acoustical properties of the B♭ trumpet were investigated. By comparing two trumpets judged to have good and poor musical quality, respectively, it was found that the air leakage at the pistons reduced theQvalue of the resonance. An irregular frequency distribution of the higher normal modes of the trumpet was also studied. The effect of the connecting condition of the tube and horn of the trumpet on the harmonic relation of the normal modes of the air column was studied. The measured resonance frequencies were found to agree well with the maximum driving point radiation resistance computed for various combinations of tube and horn.

ISSN:0001-4966    

DOI:10.1121/1.1906984

出版商:Acoustical Society of America    

年代:1953

数据来源: AIP

摘要:

A study was undertaken to obtain the free‐field and the coupler calibrations of several probe‐tube microphones with tubes of different sizes and to determine those characteristics of a probe tube which are necessary for accurate measurements in both a free field and in closed couplers. For accurate measurements with a probe‐tube microphone, precautionary measures must be taken. The probe tube must be sealed to the frame of the microphone in order to prevent an acoustic leak. Such a leak causes reduction in the output of the probe‐tube microphone at the lower frequencies. A probe tube with a high input impedance should be used for making measurements in a closed coupler. A high input impedance is necessary if the pressure in the coupler is to remain the same as before the insertion of the probe tube. If measurements are to be made with the accuracy of measurements made with a standard laboratory microphone, there is a significant difference between the pressure and the free‐field calibrations of probe‐tube microphones.

ISSN:0001-4966    

DOI:10.1121/1.1906985

出版商:Acoustical Society of America    

年代:1953

数据来源: AIP

摘要:

Electromechanical pick‐ups have been calibrated in the frequency range from 250 to 7000 cps using an interferometer to measure the vibration amplitude. A description of the theory and the experimental method is given.

ISSN:0001-4966    

DOI:10.1121/1.1906987

出版商:Acoustical Society of America    

年代:1953

数据来源: AIP

摘要:

A jet‐edge‐resonator (JER) whistle consists essentially of a jet‐edge (JE) system, such as may itself produce edge tones, and a resonator. Sound fields generated by such sources are described, as well as dependence of various aspects of these fields on airflow and whistle dimensions. Empirical findings are interpreted in terms of independently determined properties of JE systems and of resonators. A method is described for adjustment of a given whistle to maximum or near‐maximum output for a given frequency. Typical output data so obtained are presented for each of several models. Approximate values are also given of the modulation coefficientMfor various circumstances. This quantity is an index of effectiveness with which steady flow into a whistle is converted into a sinusoidally varying flow out of its mouth.

ISSN:0001-4966    

DOI:10.1121/1.1906988

出版商:Acoustical Society of America    

年代:1953

数据来源: AIP

摘要:

When a thin, flat plate executing linear oscillations in its own plane is immersed in a liquid, shear waves are set up in the liquid, and the liquid exerts a retarding force on the plate. This force, which can be measured by means of an electromechanical transducer to which the vibrating plate is coupled, is a function of the product ηρ of the coefficient of viscosity and the density of the liquid. Electrical measurements thus permit a computation of the value of ηρ. A viscometer which operates on this principle and is simple in both construction and use is described. This instrument gives instantaneous indications of ηρ over a wide range and also permits continuous indications of ηρ as a function of time to be made. A theory based on the impedance offered to an infinite vibrating plate by a liquid in which it is immersed is shown experimentally to give a valid, approximate description of the performance of the vibrating‐plate viscometer in its practical form.

ISSN:0001-4966    

DOI:10.1121/1.1906989

出版商:Acoustical Society of America    

年代:1953

数据来源: AIP

摘要:

Simple experiments are described by which some acoustical and elastic properties of lead, copper, and aluminum at liquid nitrogen temperature are partly substantiated, partly disproved. Further investigations by ultrasonical methods are in progress to find a theoretical explanation for the remarkable behavior of these metals.

ISSN:0001-4966    

DOI:10.1121/1.1906991

出版商:Acoustical Society of America    

年代:1953

数据来源: AIP

ISSN:0001-4966    

DOI:10.1121/1.1906992

出版商:Acoustical Society of America    

年代:1953

数据来源: AIP

ISSN:0001-4966    

DOI:10.1121/1.1906994

出版商:Acoustical Society of America    

年代:1953

数据来源: AIP

ISSN:0001-4966    

DOI:10.1121/1.1906995

出版商:Acoustical Society of America    

年代:1953

数据来源: AIP