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Acoustic Membrane
Acoustic membranes are flexible membranes used to produce, transmit or regulate sound, ranging from the simple to complex. In musical instruments such as drums, it is the drumhead that is vibrated to produce sound; in microphones and loudspeakers, it is diaphragms and cones that transfer sound waves to and from electricity to play music and facilitate communication. Not merely a device used to produce sound, it is also used to prevent it—barium-free viscoelastic polymers such as Acoustiblok, at merely 1/8-to-1/4-inch thickness, or Tecsound 50 heavy-duty vinyl, block out their way with their energy-converting function turning over to heat to silence walls and floors. Amazing as that is, research continues to break boundaries; ultrathin self-healing membranes composed of polyborodimethylsiloxane effectively absorb low-frequency noise (200–1000 Hz) with over 95% efficiency and restore their acoustic function once injured to open new doors to construction, automotive and aerospac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Two Dim Standing Wave
2 (two) is a number, numeral and digit. It is the natural number following 1 and preceding 3. It is the smallest and the only even prime number. Because it forms the basis of a duality, it has religious and spiritual significance in many cultures. Mathematics The number 2 is the second natural number after 1. Each natural number, including 2, is constructed by succession, that is, by adding 1 to the previous natural number. 2 is the smallest and the only even prime number, and the first Ramanujan prime. It is also the first superior highly composite number, and the first colossally abundant number. An integer is determined to be even if it is divisible by two. When written in base 10, all multiples of 2 will end in 0, 2, 4, 6, or 8; more generally, in any even base, even numbers will end with an even digit. A digon is a polygon with two sides (or edges) and two vertices. Two distinct points in a plane are always sufficient to define a unique line in a nontrivial ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Membrane ExampleA
A membrane is a selective barrier; it allows some things to pass through but stops others. Such things may be molecules, ions, or other small particles. Membranes can be generally classified into synthetic membranes and biological membranes. Biological membranes include cell membranes (outer coverings of cells or organelles that allow passage of certain constituents); nuclear membranes, which cover a cell nucleus; and tissue membranes, such as mucosae and serosae. Synthetic membranes are made by humans for use in laboratories and industry (such as chemical plants). This concept of a membrane has been known since the eighteenth century but was used little outside of the laboratory until the end of World War II. Drinking water supplies in Europe had been compromised by The War and membrane filters were used to test for water safety. However, due to the lack of reliability, slow operation, reduced selectivity and elevated costs, membranes were not widely exploited. The first use ... [...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 frequency, 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, allowing some to even hear ultrasounds. Definition Sound is defined as "(a) Oscillation in pressure, stress, particle displacement, particle velocity, etc., propagated in a medium with internal forces (e.g., elastic or viscous), or the superposition of such propagated oscillation. (b) Auditory sen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Drum
The drum is a member of the percussion group of musical instruments. In the Hornbostel–Sachs classification system, it is a membranophone. Drums consist of at least one membrane, called a drumhead or drum skin, that is stretched over a shell and struck, either directly with the player's hands, or with a percussion mallet, to produce sound. There is usually a resonant head on the underside of the drum. Other techniques have been used to cause drums to make sound, such as the thumb roll. Drums are the world's oldest and most ubiquitous musical instruments, and the basic design has remained virtually unchanged for thousands of years. Drums may be played individually, with the player using a single drum, and some drums such as the djembe are almost always played in this way. Others are normally played in a set of two or more, all played by one player, such as bongo drums and timpani. A number of different drums together with cymbals form the basic modern drum kit. Many ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acoustiblok
Acoustiblok, a registered trademark of Acoustiblok Inc., is manufactured in the United States. It is a sound attenuation material that was introduced in 1999. It is implemented in new construction and remodeling projects. It is designed to be applied behind drywall and other finishing materials. Physical properties Acoustiblok is a mass-loaded vinyl sound isolation product. It is a dense yet flexible material that comes in two sizes; 16oz. and 32oz. * 16oz Acoustiblok is 1/8" thick and has a surface mass density of 1 lb/ft2. * 32oz Acoustiblok is 1/4" thick and has a surface mass density of 2 lb/ft2. The manufacturer claims it is barium-free, has high UV resistance and has no fungal or algal growth. Performance data The ability of a partition to block the transmission of airborne sound can be described by a single number rating of the Sound Transmission Class (STC). * The 16oz version of Acoustiblok meets an STC of 26. * The 32oz version of Acoustiblok meets ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Membranophone
A membranophone is any musical instrument which produces sound primarily by way of a acoustic membrane, vibrating stretched membrane. It is one of the four main divisions of instruments in the original Hornbostel-Sachs scheme of musical instrument classification. According to Curt Sachs, Sachs, Hornbostel-Sachs The Hornbostel-Sachs scheme of musical instrument classification divides membranophones in a numeric taxonomy based on how the sound is produced: *21: by hitting the drumskin with a hand or object (most common form, including the timpani and snare drum) *22: by pulling a knotted string attached to the drumskin (common in Indian drums, and can be considered an example of a chordophone as well) *23: by rubbing the drumskin with a hand or object (common in Irish traditional music, an example is the bodhran) *24: by modifying sounds through a vibrating membrane (unusual form, including the kazoo) Length and breadth Membranophones can also be divided into small divisions bas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vibrations Of A Circular Membrane
A two-dimensional elastic membrane under tension can support transverse vibrations. The properties of an idealized drumhead can be modeled by the vibrations of a circular membrane of uniform thickness, attached to a rigid frame. Due to the phenomenon of resonance, at certain vibration frequencies, its resonant frequencies, the membrane can store vibrational energy, the surface moving in a characteristic pattern of standing waves. This is called a normal mode. A membrane has an infinite number of these normal modes, starting with a lowest frequency one called the fundamental frequency. There exist infinitely many ways in which a membrane can vibrate, each depending on the shape of the membrane at some initial time, and the transverse velocity of each point on the membrane at that time. The vibrations of the membrane are given by the solutions of the two-dimensional wave equation with Dirichlet boundary conditions which represent the constraint of the frame. It can be shown ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acoustics
Acoustics is a branch of physics that deals with the study of mechanical waves in gases, liquids, and solids including topics such as vibration, sound, ultrasound and infrasound. A scientist who works in the field of acoustics is an acoustician while someone working in the field of acoustics technology may be called an Acoustical engineering, acoustical engineer. The application of acoustics is present in almost all aspects of modern society with the most obvious being the audio and noise control industries. Hearing (sense), Hearing is one of the most crucial means of survival in the animal world and speech is one of the most distinctive characteristics of human development and culture. Accordingly, the science of acoustics spreads across many facets of human society—music, medicine, architecture, industrial production, warfare and more. Likewise, animal species such as songbirds and frogs use sound and hearing as a key element of mating rituals or for marking territories. Art, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
