Volume 15, Issue 2, October 1943
Index of content:
15(1943); http://dx.doi.org/10.1121/1.1916234View Description Hide Description
The empirical Pielemeier equation used for measuring the absorption of sound in gases is derived from theoretical consideration of the principles of the Pierce interferometer and the quartz oscillator. A more complete explanation of the effect of sound resonance on the oscillator is given. The criteria for accurate measurement of the absorption coefficients in gases are set up and verified by experiment.
15(1943); http://dx.doi.org/10.1121/1.1916235View Description Hide Description
Modern facilities for development and research in all branches of acoustics are provided in the new RCA Laboratories. The new Acoustic Laboratories include the following: a free‐field sound room, a large sound stage, a standard living room, a soundproof room for life tests, dust‐free rooms, magnetic laboratory, a live room, a field laboratory and towers, and conventional communication type laboratories. The free‐field sound room is designed to provide acoustical conditions as obtained in free space outdoors under ideal and normal test conditions. The large sound stage is designed for tests of sound pick‐up in standard conventional settings. By a change in “acoustics” the sound stage may be converted into a small theater for sound reproduction tests. The living room laboratory is designed to be the acoustical equal of the ideal living room in which sound reproducing instruments such as radios and phonographs may be developed and tested for normal home use. The soundproof room is provided with special walls and doors for testingloudspeakers at high levels without annoyance to adjoining rooms. The magnetic laboratory is equipped with apparatus for making magnetic measurements and several types of magnetizers for magnetizing permanent magnets. The dust‐free rooms are used for assembling structures. The live room is designed for testing of sound‐absorbingmaterials. The conventional laboratory bays include all types of measuring equipment: oscillators,amplifiers, recorders, bridges, etc. Multiple audiofrequency lines are provided so that laboratories may be interconnected. The remotely located field laboratory is used for conducting free‐field response, power, and life tests.
15(1943); http://dx.doi.org/10.1121/1.1916236View Description Hide Description
15(1943); http://dx.doi.org/10.1121/1.1916237View Description Hide Description
15(1943); http://dx.doi.org/10.1121/1.1916244View Description Hide Description