1 : an 8-day period of observances beginning with a festival day. 2a : a stanza of eight lines : ottava rima. b : the first eight lines of an Italian sonnet. 3a : a musical interval embracing eight diatonic degrees.

Beat, in physics, the pulsation caused by the combination of two waves of slightly different frequencies. The resulting sound is alternately soft and loud—that is, having characteristic pulsations, or throbs, called beats.

The beat frequency is always equal to the difference in frequency of the two notes that interfere to produce the beats. So if two sound waves with frequencies of 256 Hz and 254 Hz are played simultaneously, a beat frequency of 2 Hz will be detected.

First, determine the number of octaves between the two frequencies. Keep in mind that an octave is the doubling of the frequency. So going from 1Hz to 2Hz is an octave and going from 1000Hz to 2000Hz is also an octave….

Octave, in music, an interval whose higher note has a sound-wave frequency of vibration twice that of its lower note. Thus the international standard pitch A above middle C vibrates at 440 hertz (cycles per second); the octave above this A vibrates at 880 hertz, while the octave below it vibrates at 220 hertz.

The Greeks realized that sounds which have frequencies in rational proportion are perceived as harmonius. For example, a doubling of frequency gives an octave. A tripling of frequency gives a perfect fifth one octave higher. They didn’t know this in terms of frequencies, but in terms of lengths of vibrating strings.

The next pitch is called the octave because it’s the eighth note (just as an octopus has eight legs). More than a thousand years ago the letters of the Roman alphabet were adopted to refer to these, and since there were only seven the letters ran A, B, C, D, E, F, G.

By dividing each octave into 12 intervals, you maximize the number of pleasingly sounding pairs of notes. That is because the number 12 is divisible by more small numbers than any other number less than 60. It is divisible by 1,2,3,4,and 6. So in modern western music they use 12 intervals.

Doubling the frequency of a wave source (without altering the medium) doubles the speed of the waves. Don’t be fooled. Wave speed may equal frequency*wavelength. Yet doubling the frequency only halves the wavelength; wave speed remains the same.

In terms of physics, an octave is the distance between one note and another note that’s double its frequency..

The number of complete wavelengths in a given unit of time is called frequency (f). As a wavelength increases in size, its frequency and energy (E) decrease. From these equations you may realize that as the frequency increases, the wavelength gets shorter. As the frequency decreases, the wavelength gets longer.

If the frequency of the wave is doubled, the period becomes halved.

101 million cycles

The Doppler effect is a change in the frequency of sound waves that occurs when the source of the sound waves is moving relative to a stationary listener. As the source of sound waves approaches a listener, the sound waves get closer together, increasing their frequency and the pitch of the sound.

The ground heats (and cools) the air near it. Normally the ground is warmer than the air above, so air temperature decreases with height in the troposphere (up to about 8 miles). Sound travels faster in warmer air, so the sound waves are refracted upward, away from the ground.

In short, sound is omnidirectional, meaning that it can travel in all directions, including up and down. So, as you can see, while sound travels in all directions, the amount of noise you hear depends on several different factors. …

Basically, for every 10 dB increase, we’re adding a zero to the amount of intensity versus the threshold of hearing….That’s Intense: Understanding the Decibel Scale.

Particles of matter are packed more tightly in the ground than in the air. The reason is that sound waves are vibrations of the molecules of the medium: therefore, if the particles of the medium are closer together (as in solids), the vibrations can be transmitted faster, and the wave can travel faster.

As it turns out, there’s a scientific reason behind the calming silence, with the characteristics of snow playing a big role in how sound can travel. When light, fluffy snow accumulates on the ground, it acts as a sound absorber, dampening sound waves much like commercial sound absorbing products.

As a rule sound travels slowest through gases, faster through liquids, and fastest through solids. The speed of light as it travels through air and space is much faster than that of sound; it travels at 300 million meters per second or 273,400 miles per hour.

Sound travels faster in water compared with air because water particles are packed in more densely. Thus, the energy the sound waves carry is transported faster. This should make the sound appear louder.

Krakatoa

Sperm whales are so loud that their clicks are capable of killing a human within their vicinity, says one science and adventure journalist. “These clicks are so powerful in the water that they can blow out your eardrums easily, and they can actually vibrate a human body to death,” he said.

Yes. Sound can absolutely kill you if it’s loud enough. Sound is created by a pressure wave which vibrates particles as it travels in an accordion-like manner. A vibrating source pushes particles forwards with a high-pressure wave.

The general consensus is that a loud enough sound could cause an air embolism in your lungs, which then travels to your heart and kills you. Alternatively, your lungs might simply burst from the increased air pressure. High-intensity ultrasonic sound (generally anything above 20KHz) can cause physical damage.

The most dangerous frequency is at the median alpha-rhythm frequencies of the brain, 7 hz. This is also the resonant frequency of the body’s organs.

However, a 2017 study that measured the effects of binaural beat therapy using EEG monitoring found that binaural beat therapy does not affect brain activity or emotional stimulation.