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VRAS
The Variable Room Acoustics System is an acoustic enhancement system for controlling room acoustics electronically. Such systems are increasingly being used to provide variable acoustics for multipurpose venues. VRAS uses multiple microphones distributed around the room, fed via a multichannel digital reverberator to multiple loudspeakers to provide controllable enhancement of the reverberation time of the room. It is an example of a non-in-line or regenerative sound system which uses the inherent feedback of sound from the loudspeakers to the microphones to enhance the reverberation time for all sound source positions within the room. VRAS uses a unitary reverberator which maintains a constant power gain with frequency so that its inclusion does not affect the stability of the system (at each frequency the reverberator is a unitary matrix). M. A. Poletti, ”The stability of single and multichannel sound systems,” Acustica-Acta Acustica, vol. 86, pp 123-178, 2000/ref> In additi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acoustic Enhancement
Acoustic enhancement is a subtle type of sound reinforcement system used to augment direct, reflected, or reverberant sound. While sound reinforcement systems are usually used to increase the sound level of the sound source (like a person speaking into a microphone, or musical instruments in a pop ensemble), acoustic enhancement systems are typically used to increase the acoustic energy in the venue in a manner that is not noticed by the audience. The correctly installed systems replicate the desired acoustics of early reflections and reverberation from a room that is properly designed for Acoustic Music. An additional benefit of these systems is that the room acoustics can be changed or adjusted to be matched to the type of performance. The use of Acoustic Enhancement as Electronic Architecture offers a good solution for multi-use performance halls that need to be "dead" for amplified music , and are used occasionally for acoustic performances. These systems are often associa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Unitary Matrix
In linear algebra, a complex square matrix is unitary if its conjugate transpose is also its inverse, that is, if U^* U = UU^* = UU^ = I, where is the identity matrix. In physics, especially in quantum mechanics, the conjugate transpose is referred to as the Hermitian adjoint of a matrix and is denoted by a dagger (†), so the equation above is written U^\dagger U = UU^\dagger = I. The real analogue of a unitary matrix is an orthogonal matrix. Unitary matrices have significant importance in quantum mechanics because they preserve norms, and thus, probability amplitudes. Properties For any unitary matrix of finite size, the following hold: * Given two complex vectors and , multiplication by preserves their inner product; that is, . * is normal (U^* U = UU^*). * is diagonalizable; that is, is unitarily similar to a diagonal matrix, as a consequence of the spectral theorem. Thus, has a decomposition of the form U = VDV^*, where is unitary, and is diagonal and uni ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Architectural Acoustics
Architectural acoustics (also known as building acoustics) is the science and engineering of achieving a good sound within a building and is a branch of acoustical engineering. The first application of modern scientific methods to architectural acoustics was carried out by the American physicist Wallace Sabine in the Fogg Museum lecture room. He applied his newfound knowledge to the design of Symphony Hall, Boston. Architectural acoustics can be about achieving good speech intelligibility in a theatre, restaurant or railway station, enhancing the quality of music in a concert hall or recording studio, or suppressing noise to make offices and homes more productive and pleasant places to work and live in. Architectural acoustic design is usually done by acoustic consultants. Building skin envelope This science analyzes noise transmission from building exterior envelope to interior and vice versa. The main noise paths are roofs, eaves, walls, windows, door and penetrations. S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reverberation
Reverberation (also known as reverb), in acoustics, is a persistence of sound, after a sound is produced. Reverberation is created when a sound or signal is reflected causing numerous reflections to build up and then decay as the sound is absorbed by the surfaces of objects in the space – which could include furniture, people, and air. This is most noticeable when the sound source stops but the reflections continue, their amplitude decreasing, until zero is reached. Reverberation is frequency dependent: the length of the decay, or reverberation time, receives special consideration in the architectural design of spaces which need to have specific reverberation times to achieve optimum performance for their intended activity. In comparison to a distinct echo, that is detectable at a minimum of 50 to 100 ms after the previous sound, reverberation is the occurrence of reflections that arrive in a sequence of less than approximately 50 ms. As time passes, the amplitude of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Room Acoustics
Room acoustics is a subfield of acoustics dealing with the behaviour of sound in enclosed or partially-enclosed spaces. The architectural details of a room influences the behaviour of sound waves within it, with the effects varying by frequency. Acoustic reflection, diffraction, and diffusion can combine to create audible phenomena such as room modes and standing waves at specific frequencies and locations, echos, and unique reverberation patterns. Frequency zones The way that sound behaves in a room can be broken up into roughly four different frequency zones: *The first zone is below the frequency that has a wavelength of twice the longest length of the room. In this zone, sound behaves very much like changes in static air pressure. *Above that zone, until wavelengths are comparable to the dimensions of the room, room resonances dominate. This transition frequency is popularly known as the Schroeder frequency, or the cross-over frequency and it differentiates the low fr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
