Search results
Results from the WOW.Com Content Network
One disk was stationary, while the other disk rotated. The rotating disk periodically interrupted the flow of air through the fixed disk, producing a tone. [5] [6] De la Tour's siren could produce sound under water, [7] suggesting a link with the sirens of Greek mythology; hence the name he gave to the instrument. [8]
Upsweep is an unidentified sound detected on the American NOAA's equatorial autonomous hydrophone arrays. This sound was present when the Pacific Marine Environmental Laboratory began recording its sound surveillance system, SOSUS, in August 1991. It consists of a long train of narrow-band upsweeping sounds of several seconds in duration each.
A 1973 report cites a university study of fifty cases of people complaining about a "low throbbing background noise" that others were unable to hear. The sound, always peaking between 30 and 40 Hz (hertz), was found to only be heard during cool weather with a light breeze, and often early in the morning. These noises were often confined to a 10 ...
This is typically a one-second burst of sound to verify the proper operation of the siren without causing a significant number of people to interpret the test as an actual alert. Many cities in the U.S. periodically sound their sirens as a test, either weekly, monthly, or yearly, at a day and hour set by each individual city. [citation needed]
Ripa and Mark Consuelos discussed the start of Spooky Season as ominous music sounded from the deepest corners of the "Live" studio.
Interruptible foldback (IFB), also known as interrupted foldback, interruptible feedback, or interrupt for broadcast, is a monitoring and cueing system used in television, filmmaking, video production, and radio broadcast for one-way communication from the director or assistant director to on-air talent or a remote location.
These active detectors transmit ultrasonic sound waves that are inaudible to humans using frequencies between 15 kHz and 75 kHz. The Doppler shift principle is the underlying method of operation which detects a change in frequency due to object motion. This detection occurs when the object must cause a change in the ultrasonic frequency to the ...
A rest is the absence of a sound for a defined period of time in music, or one of the musical notation signs used to indicate that. The length of a rest corresponds with that of a particular note value, thus indicating how long the silence should last. Each type of rest is named for the note value it corresponds with (e.g. quarter note and ...