3/24/2024 0 Comments Diffraction of sound exampleThese properties intertwine to craft the unique signature of every sound we hear. The nature of sound is captured through its fundamental characteristics: wavelength (the distance between wave peaks), amplitude (the height of the wave, corresponding to loudness), frequency (the number of waves passing a point per second, related to pitch), time period (the time it takes for one complete wave cycle to occur), and velocity (the speed at which the wave travels through a medium). Metal, wood, stone, glass, water, and many other substances conduct sound - many of them even better than air. Technically, sound is defined as a mechanical disturbance traveling through an elastic medium - a material that tends to return to its original condition after being deformed. Wavelength is the distance between any point on a wave and the corresponding point on the next wave. Ultrasound is sound with frequencies above the range of human hearing-that is, above 20,000 hertz. Sound quality distinguishes between notes of the same frequency and intensity that are produced by different musical instruments. Sound quality, also called timbre, is a characteristic of musical sounds. Sound medium is a substance in which sound waves travel. Resonance frequency is the frequency at which an object would vibrate naturally if disturbed. Rarefaction is a region in a sound wave in which the density of the sound medium is less than normal. Pitch is the degree of highness or lowness of a sound as we hear it. Noise is a sound that is unpleasant, annoying, and distracting. Loudness refers to how strong a sound seems when we hear it. Intensity of a sound is a measure of the power of its waves. One hertz equals one cycle (vibration, or sound wave) per second. Hertz is the unit used to measure frequency of sound waves. A 3,000-hertz tone of 0 dB is the softest sound that a normal human ear can hear.įrequency of a sound is the number of sound waves that pass a given point each second. Acoustics is the science of sound and of its effects on people.Ĭondensation is a region in a sound wave in which the sound medium is denser than normal.ĭecibel (dB) is the unit used to measure the intensity of a sound. For instance, the TWEETER of a loudspeaker is shaped in the form of a fan for this purpose. Īs a result of their capability of diffraction, low frequency sounds are difficult to localize or contain in an environment (see CANYON EFFECT, DIFFUSE SOUND FIELD ).Īn acoustic radiator must be specially designed for good dispersion of high frequencies since this does not occur naturally through diffraction. Ĭompare: CANCELLATION, INTERFERENCE, PARABOLIC REFLECTOR, REFLECTION, REFRACTION. Thus, diffraction may aid sound dispersion and DIFFUSION. When the wavelength is similar to the dimensions of the object, as with low frequencies and buildings, or mid-range frequencies and the head, the wave diffracts around the object, using its edges as a focal point from which to generate a new wavefront of the same frequency but reduced intensity. Low frequency sounds have wavelengths that are much longer than most objects and barriers, and therefore such waves pass around them undisturbed. Such is the case with high frequencies with respect to the head, and thus is important in BINAURAL HEARING. High frequency sounds, with short wavelengths, do not diffract around most obstacles, but are absorbed or reflected instead, creating a SOUND SHADOW behind the object. The phenomenon in SOUND PROPAGATION whereby a SOUND WAVE moves around an object whose dimensions are smaller than or about equal to the WAVELENGTH of the sound.
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