the measurement of low or high sound is called audible frequency.
the measurement of low or high sound is called audible frequency.
what is the measurement of low or high sound called?
audible frequency
bullet::::- aspect ratio – sound level increases as whistle length is reduced, increasing frequency. for example, depressing the piston of a variable-pitch steam whistle changed the frequency from 333 hz to 753 hz and raised the sound pressure level from 116 dbc to 123 dbc. that five-fold difference in the square of the frequency resulted in a five-fold difference in sound intensity. sound level also increases as whistle cross-sectional area is increased. a sample of 12 single-note whistles ranging in size from one-inch diameter to 12-inches diameter showed a relationship between sound intensity and the square of the cross-sectional area (when differences in frequency were taken into account). in other words, relative whistle sound intensity can be estimated using the square of the cross-sectional area divided by the square of the wavelength. for example, the sound intensity from a whistle bell of 6-inch diameter x 7.5-inch length (113 dbc) was 10x that of a 2 x 4-inch whistle (103 dbc) and twice that of a (lower frequency) 10 x 40-inch whistle (110 dbc). these whistles were sounded on compressed air at 125 pounds per square inch gauge pressure (862 kilopascals) and sound levels were recorded at 100 feet distance. elongate organ whistles may exhibit disproportionately high sound levels due to their strong higher frequency overtones. at a separate venue a 20-inch diameter ultrawhistle (ring-shaped whistle) operating at 15 pounds per square inch gauge pressure (103.4 kilopascals) produced 124 dbc at 100 feet. it is unknown how the sound level of this whistle would compare to that of a conventional whistle of the same frequency and resonant chamber area. by comparison, a bell-chrysler air raid siren generates 138 dbc at 100 feet. the sound level of a levavasseur toroidal whistle is enhanced by about 10 decibels by a secondary cavity parallel to the resonant cavity, the former creating a vortex that augments the oscillations of the jet driving the whistle.
steam whistle
automobiles are not well suited for the "hidden" subwoofer approach due to space limitations in the passenger compartments. it is not possible, in most circumstances, to fit such large drivers and enclosures into doors or dashboards, so subwoofers are installed in the trunk or back seat space. some car audio enthusiasts compete to produce very high sound pressure levels in the confines of their vehicle's cabin; sometimes dangerously high. the "spl wars" have drawn much attention to subwoofers in general, but subjective competitions in sound quality ("sq") have not gained equivalent popularity. top spl cars are not able to play normal music, or perhaps even to drive normally as they are designed solely for competition. many non-competition subwoofers are also capable of generating high levels in cars due to the small volume of a typical car interior. high sound levels can cause hearing loss and tinnitus if one is exposed to them for an extended period of time.
subwoofer