from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. An instrument for measuring sounds.
from the GNU version of the Collaborative International Dictionary of English
- n. An instrument for measuring sounds, as to their intensity, or the frequency of the vibrations.
from The Century Dictionary and Cyclopedia
- n. An instrument for experimentally determining and exhibiting the number of vibrations of a sonorous body (as a string or tuning-fork) in a unit of time.
- n. In psychophysics, an instrument for the production of accurately graded intensities of sound. The simplest form of phonometer is the sound-pendulum (which see). In Wundt's gravity-phonometer, ivory balls are dropped by electromagnetic releases from varying heights upon hard-wood plates.
- n. A clockwork instrument swung in gimbals, so that its face is always horizontal, and on whose dial are certain marks indicating intervals at which a whistle or other signal should be made to announce the compass course of the vessel.
So it is only necessary to twist the phonometer about on its pivot until the sound is received most loudly in the horns and the band of light is greatest.
Banging and pounding, we forged ahead, straining our eyes to watch the road, the distance, the time, and the phonometer all at once.
Without the phonometer to warn us, it must inevitably have met us and blocked our escape over the road ahead.
The sound enters the two horns of the phonometer, is focused at the neck, and strikes on a delicate diaphragm, behind which is a needle.