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Muzzle Blast
A muzzle blast is an explosive shockwave created at the muzzle of a firearm during shooting. Before a projectile leaves the gun barrel, it obturates the bore and "plugs up" the pressurized gaseous products of the propellant combustion behind it, essentially containing the gases within a closed system as a neutral element in the overall momentum of the system's physics. However, when the projectile exits the barrel, this functional seal is removed and the highly energetic bore gases are suddenly free to exit the muzzle and rapidly expand in the form of a supersonic shockwave (which can be often fast enough to momentarily overtake the projectile and affect its flight dynamics), thus creating the muzzle blast. The muzzle blast is often broken down into two components: an auditory component and a non-auditory component. The auditory component is the loud "Bang!" sound of the gunshot, and is important because it can cause significant hearing loss to surrounding personnel and al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Infrasonic
Infrasound, sometimes referred to as low status sound, describes sound waves with a frequency below the lower limit of human audibility (generally 20 Hz). Hearing becomes gradually less sensitive as frequency decreases, so for humans to perceive infrasound, the sound pressure must be sufficiently high. The ear is the primary organ for sensing low sound, but at higher intensities it is possible to feel infrasound vibrations in various parts of the body. The study of such sound waves is sometimes referred to as infrasonics, covering sounds beneath 20 Hz down to 0.1 Hz (and rarely to 0.001 Hz). People use this frequency range for monitoring earthquakes and volcanoes, charting rock and petroleum formations below the earth, and also in ballistocardiography and seismocardiography to study the mechanics of the heart. Infrasound is characterized by an ability to get around obstacles with little dissipation. In music, acoustic waveguide methods, such as a large pipe or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sound Pressure
Sound pressure or acoustic pressure is the local pressure deviation from the ambient (average or equilibrium) atmospheric pressure, caused by a sound wave. In air, sound pressure can be measured using a microphone, and in water with a hydrophone. The SI unit of sound pressure is the pascal (Pa). Mathematical definition A sound wave in a transmission medium causes a deviation (sound pressure, a ''dynamic'' pressure) in the local ambient pressure, a ''static'' pressure. Sound pressure, denoted ''p'', is defined by p_\text = p_\text + p, where * ''p''total is the total pressure, * ''p''stat is the static pressure. Sound measurements Sound intensity In a sound wave, the complementary variable to sound pressure is the particle velocity. Together, they determine the sound intensity of the wave. ''Sound intensity'', denoted I and measured in W· m−2 in SI units, is defined by \mathbf I = p \mathbf v, where * ''p'' is the sound pressure, * v is the particle velocity. Acoustic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sound Energy
In physics, sound energy is a form of energy that can be heard by living things. Only those waves that have a frequency of 16 Hz to 20 kHz are audible to humans. However, this range is an average and will slightly change from individual to individual. Sound waves that have frequencies below 16 Hz are called infrasonic and those above 20 kHz are called ultrasonic. Sound is a mechanical wave and as such consists physically in oscillatory elastic compression and in oscillatory displacement of a fluid. Therefore, the medium acts as storage for both potential and kinetic energy. Consequently, the sound energy in a volume of interest is defined as the sum of the potential and kinetic energy densities integrated over that volume: :W = W_\mathrm + W_\mathrm = \int_V \frac\, \mathrmV + \int_V \frac\, \mathrmV, where *''V'' is the volume of interest; *''p'' is the sound pressure; *''v'' is the particle velocity; *''ρ''0 is the density of the medium without sound present ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intensity (physics)
In physics, the intensity or flux of radiant energy is the Power (physics), power transferred per unit area, where the area is measured on the plane perpendicular to the direction of propagation of the energy. In the SI system, it has units watts per square metre (W/m2), or kilogram, kg⋅second, s−3 in SI base unit, base units. Intensity is used most frequently with waves such as acoustic waves (sound) or electromagnetic waves such as light or radio waves, in which case the time averaging, ''average'' power transfer over one Period (physics), period of the wave is used. ''Intensity'' can be applied to other circumstances where energy is transferred. For example, one could calculate the intensity of the kinetic energy carried by drops of water from a garden sprinkler. The word "intensity" as used here is not synonymous with "wikt:strength, strength", "wikt:amplitude, amplitude", "wikt:magnitude, magnitude", or "wikt:level, level", as it sometimes is in colloquial speech. Intensi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Whipcracking
Whipcracking is the act of producing a cracking sound through the use of a whip. Used during livestock driving and horse riding, it has also become an art. A rhythmic whipcracking belongs to the traditional culture among various Germanic peoples of Bavaria ('' Goaßlschnalzen''), various Alpine areas (''Aperschnalzen''), Austria, and Hungary (Ostorozás). Today it is a performing art, a part of rodeo show in United States, a competitive sport in Australia and increasingly popular in the United Kingdom, where it crosses boundaries of sport, hobby and performance. Physics The crack a whip makes is produced when a section of the whip moves faster than the speed of sound creating a small sonic boom. The creation of the sonic boom was confirmed in 1958 by analyzing the high-speed shadow photography taken in 1927.American Physical Society (2002) Whip Cracking Mystery Explained'' 26 May 2002 Recently, an additional, purely geometrical factor was recognized: the tip of the whip moves ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transonic
Transonic (or transsonic) flow is air flowing around an object at a speed that generates regions of both subsonic and supersonic airflow around that object. The exact range of speeds depends on the object's critical Mach number, but transonic flow is seen at flight speeds close to the speed of sound (343 m/s at sea level), typically between Mach 0.8 and 1.2. The issue of transonic speed (or transonic region) first appeared during World War II. Pilots found as they approached the sound barrier the airflow caused aircraft to become unsteady. Experts found that shock waves can cause large-scale separation downstream, increasing drag and adding asymmetry and unsteadiness to the flow around the vehicle. Research has been done into weakening shock waves in transonic flight through the use of anti-shock bodies and supercritical airfoils. Most modern jet powered aircraft are engineered to operate at transonic air speeds. Transonic airspeeds see a rapid increase in drag from a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sonic Boom
A sonic boom is a sound associated with shock waves created when an object travels through the air faster than the speed of sound. Sonic booms generate enormous amounts of sound energy, sounding similar to an explosion or a thunderclap to the human ear. A decibel is the primary unit measurement of sound. "A thunderclap is incredibly loud, producing levels between 100 and 120 dBA (Decibel, decibels A)- the equivalent of standing near a jet during take-off." The crack of a supersonic bullet passing overhead or the crack of a bullwhip are examples of a sonic boom in miniature. Sonic booms due to large supersonic aircraft can be particularly loud and startling, tend to awaken people, and may cause minor damage to some structures. This led to prohibition of routine supersonic flight overland. Although they cannot be completely prevented, research suggests that with careful shaping of the vehicle, the nuisance due to the sonic booms may be reduced to the point that overland super ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gunfire
A gunshot is a single discharge of a gun, typically a man-portable firearm, producing a visible flash, a powerful and loud shockwave and often chemical gunshot residue. The term can also refer to a ballistic wound caused by such a discharge. Multiple discharges of one or more firearms are referred to as gunfire. The word can connote either the sound of a gun firing, the projectiles that were fired, or both. For example, the statement "gunfire came from the next street" could either mean the sound of discharge, or it could mean the bullets that were discharged. It is better to be a bit more specific while writing however. "The sound of gunfire" or "we came under gunfire" would be more descriptive and prevent confusion. In the latter phrase, in particular, "fire" is used more (i.e. "under fire"), as both words hold the same general meaning within the proper context. Gunfire characteristics There are three primary attributes that characterize gunfire and hence enable the d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sound
In physics, sound is a vibration that propagates as an acoustic wave, through a transmission medium such as a gas, liquid or solid. In human physiology and psychology, sound is the ''reception'' of such waves and their ''perception'' by the brain. Only acoustic waves that have frequencies lying between about 20 Hz and 20 kHz, the audio frequency range, elicit an auditory percept in humans. In air at atmospheric pressure, these represent sound waves with wavelengths of to . Sound waves above 20 kHz are known as ultrasound and are not audible to humans. Sound waves below 20 Hz are known as infrasound. Different animal species have varying hearing ranges. Acoustics Acoustics is the interdisciplinary science that deals with the study of mechanical waves in gasses, liquids, and solids including vibration, sound, ultrasound, and infrasound. A scientist who works in the field of acoustics is an ''acoustician'', while someone working in the field of acoustica ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Audible Frequency
An audio frequency or audible frequency (AF) is a periodic vibration whose frequency is audible to the average human. The SI unit of frequency is the hertz (Hz). It is the property of sound that most determines pitch. The generally accepted standard hearing range for humans is 20 to 20,000 Hz. In air at atmospheric pressure, these represent sound waves with wavelengths of to . Frequencies below 20 Hz are generally felt rather than heard, assuming the amplitude of the vibration is great enough. High frequencies are the first to be affected by hearing loss due to age or prolonged exposure to very loud noises. Sound frequencies above 20 kHz are called ultrasonic. Frequencies and descriptions See also *Absolute threshold of hearing *Hypersonic effect, controversial claim for human perception above 20,000 Hz *Loudspeaker *Musical acoustics *Piano key frequencies *Scientific pitch notation *Whistle register The whistle register (also called the flute regi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Live Fire
Black MIDI is a music genre consisting of compositions that use MIDI files to create a song or a remix containing a large number of notes. People who make black MIDIs are known as blackers. However, there are no specific criteria of what is considered "black"; as a result, pinpointing the exact origin of black MIDI is impossible. Origins and early history Though the two are unrelated in origin, the concept of impossible piano existed long before black MIDI, manifesting itself for example within Conlon Nancarrow's work involving player pianos, in which he punched holes in piano rolls, creating extremely complex musical compositions in the same impossible, unplayable spirit of black MIDI. Another precursor to black MIDI is ''Circus Galop'', a player piano composition written by Canadian virtuoso Marc-Andre Hamelin, featuring complex and impossible arrangement with up to 21 notes played simultaneously. Frank Zappa also wrote a dense and extremely difficult composition called "The B ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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