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Low Frequency Effects
The low-frequency effects (LFE) channel is a band-limited audio track that is used for reproducing deep and intense low-frequency sounds in the 3–120 Hz frequency range. This track is normally sent to a subwoofer—a loudspeaker designed to reproduce very low frequencies. LFE channels originated in Dolby Stereo 70 mm film, but in the 1990s and 2000s they became common in home theater systems in order to reproduce film soundtracks found on DVDs and Blu-ray discs. Types Low-pitched musical arts LFEs include both low-pitched musical notes and low-pitched sound effects. The musical soundtrack for many films includes bass instruments that produce very low notes. Until the 1970s, most of the low-pitched instruments were natural, acoustic instruments, such as the double bass or the pipe organ's pedal keyboard. After the 1980s, film scores increasingly used synthesized instruments, including synth bass keyboards, which incorporated very low-pitched notes. Sou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Audio Signal
An audio signal is a representation of sound, typically using either a changing level of electrical voltage for analog signals or a series of binary numbers for Digital signal (signal processing), digital signals. Audio signals have frequencies in the audio frequency range of roughly 20 to 20,000 Hz, which corresponds to the lower and upper Human hearing range, limits of human hearing. Audio signals may be Synthesizer, synthesized directly, or may originate at a transducer such as a microphone, Pickup (music technology), musical instrument pickup, phonograph cartridge, or tape head. Loudspeakers or headphones convert an electrical audio signal back into sound. Digital audio systems represent audio signals in a variety of digital formats.Hodgson, Jay (2010). ''Understanding Records'', p.1. . An audio channel or audio track is an audio signal communications channel in a data storage device, storage device or mixing console. It is used in operations such as multi-track recordi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
U-571 (film)
''U-571'' is a 2000 submarine films, submarine film directed by Jonathan Mostow from a screenplay he co-wrote with Sam Montgomery and David Ayer. The film stars Matthew McConaughey, Bill Paxton, Harvey Keitel, Jon Bon Jovi, Jake Weber and Matthew Settle. The film follows a World War II German U-boat boarded by American submariners to capture her Enigma cipher machine. Although the film was financially successful and received generally positive reviews from critics, winning the Academy Award for Academy Award for Best Sound, Best Sound Editing, the fictitious plot was subject to substantial controversy and criticism. Plot In May 1942, during the Battle of the Atlantic, after sinking a British merchant ship, German U-boat ''U-571'' has her engines badly damaged by depth charges from a British destroyer, with all of her engineers and mechanics killed in a flash fire. ''U-571'' skipper ''Kapitänleutnant'' Günther Wassner makes a distress call that is intercepted by Allied intelli ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bass Management
The fundamental principle of bass management (also called LFE crossover) in surround sound replay systems is that bass content in the incoming signal, irrespective of channel, should be directed only to loudspeakers capable of reproducing it, whether the latter are the main system loudspeakers or one or more subwoofers. Mapping There are notation differences between the pre-bass-managed signal and after it has passed through the bass manager. For example, when using 5.1 surround sound: As the table shows, the bass manager directs bass frequencies from ''all'' channels to one or more subwoofers, not just the content of the low-frequency effects The low-frequency effects (LFE) channel is a band-limited Audio signal, audio track that is used for reproducing deep and intense low-frequency sounds in the 3–120 Hertz, Hz frequency range. This track is normally sent to a subwoofer—a ... (LFE) channel. However, when there is no subwoofer, the bass manager directs the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tactile Transducer
A tactile transducer or "bass shaker" is a device which is made on the principle that low bass frequencies can be felt as well as heard. They can be compared with a common loudspeaker, just that the diaphragm is missing. Instead, another object is used as a diaphragm. A shaker transmits low-frequency vibrations into various surfaces so that they can be felt by people. This is called tactile sound. Tactile transducers may augment or in some cases substitute for a subwoofer. One benefit of tactile transducers is they produce little or no noise, if properly installed, as compared with a subwoofer speaker enclosure. Applications A bass-shaker is meant to be firmly attached to some surface such as a seat, couch or floor. The shaker houses a small weight which is driven by a voice coil similar to those found in dynamic loudspeakers. The voice-coil is driven by a low-frequency audio signal from an amplifier; common shakers typically handle 25 to 50 watts of amplifier power. The voice c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bass Management
The fundamental principle of bass management (also called LFE crossover) in surround sound replay systems is that bass content in the incoming signal, irrespective of channel, should be directed only to loudspeakers capable of reproducing it, whether the latter are the main system loudspeakers or one or more subwoofers. Mapping There are notation differences between the pre-bass-managed signal and after it has passed through the bass manager. For example, when using 5.1 surround sound: As the table shows, the bass manager directs bass frequencies from ''all'' channels to one or more subwoofers, not just the content of the low-frequency effects The low-frequency effects (LFE) channel is a band-limited Audio signal, audio track that is used for reproducing deep and intense low-frequency sounds in the 3–120 Hertz, Hz frequency range. This track is normally sent to a subwoofer—a ... (LFE) channel. However, when there is no subwoofer, the bass manager directs the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Home Theater In A Box
A home theater in a box (HTIB) is an integrated home theater package which "bundles" together a combination DVD or Blu-ray player, a multi-channel amplifier (which includes a surround sound decoder, a radio tuner, and other features), speaker wires, connection cables, a remote control, a set of five or more surround sound speakers (or more rarely, just left and right speakers, a lower-price option known as "2.1") and a low-frequency subwoofer cabinet. Manufacturers also have come out with the "soundbar", an all in one device to put underneath the television and that contains all the speakers in one unit. Market positioning HTIBs are marketed as an "all-in-one" way for consumers to enjoy the surround sound Surround sound is a technique for enriching the fidelity and depth of sound reproduction by using multiple audio channels from speakers that surround the listener ( surround channels). Its first application was in movie theaters. Prior to ... experience of home cin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dolby Surround
Dolby Pro Logic is a surround sound processing technology developed by Dolby Laboratories, designed to decode soundtracks encoded with Dolby Surround. The terms Dolby Stereo and LtRt (''Left Total'', ''Right Total'') are also used to describe soundtracks that are encoded using this technique. Dolby Stereo—also known as Dolby MP (''Motion Picture'') or Dolby SVA (''stereo variable-area'')—was developed by Dolby in 1976 for analog cinema sound systems. The format was adapted for home use in 1982 as Dolby Surround when HiFi capable consumer VCRs were introduced. It was further improved with the Dolby Pro Logic decoding system after 1987. The Dolby MP Matrix was the professional system that encoded four channels of film sound into two. This track used by the ''Dolby Stereo'' theater system on a 35mm optical stereo print and decoded back to the original 4.0 Surround. The same four-channel encoded stereo track was largely left unchanged and made available to consumers as ''"Do ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dolby Pro Logic
Dolby Pro Logic is a surround sound processing technology developed by Dolby Laboratories, designed to decode soundtracks encoded with Dolby Surround. The terms Dolby Stereo and LtRt (''Left Total'', ''Right Total'') are also used to describe soundtracks that are encoded using this technique. Dolby Stereo—also known as Dolby MP (''Motion Picture'') or Dolby SVA (''stereo variable-area'')—was developed by Dolby in 1976 for analog movie theater, cinema sound systems. The format was adapted for home use in 1982 as Dolby Surround when VCR#Stereo Sound and HiFi, HiFi capable consumer VCRs were introduced. It was further improved with the Dolby Pro Logic decoding system after 1987. The Dolby MP Matrix was the professional system that encoded four channels of film sound into two. This track used by the ''Dolby Stereo'' theater system on a 35mm optical stereo print and decoded back to the original 4.0 Surround. The same four-channel encoded stereo track was largely left unchanged a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Surround Sound
Surround sound is a technique for enriching the fidelity and depth of sound reproduction by using multiple audio channels from speakers that surround the listener ( surround channels). Its first application was in movie theaters. Prior to surround sound, theater sound systems commonly had three ''screen channels'' of sound that played from three loudspeakers (left, center, and right) located in front of the audience. Surround sound adds one or more channels from loudspeakers to the side or behind the listener that are able to create the sensation of sound coming from any horizontal direction (at ground level) around the listener. The technique enhances the perception of sound spatialization by exploiting sound localization: a listener's ability to identify the location or origin of a detected sound in direction and distance. This is achieved by using multiple discrete audio channels routed to an array of loudspeakers. Surround sound typically has a listener location ( sweet ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
70 Mm Film
70 mm film (or 65 mm film) is a wide high-resolution film gauge for motion picture photography, with a negative area nearly 3.5 times as large as the standard 35 mm motion picture film format. As used in cameras, the film is wide. For projection, the original 65 mm film is printed on film. The additional 5 mm contains the four magnetic stripes, holding six tracks of stereophonic sound. Although later 70 mm prints use digital sound encoding (specifically the DTS format), the vast majority of existing and surviving 70 mm prints pre-date this technology. Each frame is five perforations tall (i.e., 23.8125 mm or 15/16 inches tall), with an image aspect ratio of 2.2:1. The use of anamorphic Ultra Panavision 70 lenses squeezes an ultra-wide 2.76:1 aspect ratio horizontally into that 2.2:1 imaging area. To this day, Ultra Panavision 70 produces the widest picture size in the history of filmmaking; surpassed only by Polyvision, which was on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dolby Digital
Dolby Digital, originally synonymous with Dolby AC-3 (see below), is the name for a family of audio compression technologies developed by Dolby Laboratories. Called Dolby Stereo Digital until 1995, it is lossy compression (except for Dolby TrueHD). The first use of Dolby Digital was to provide digital sound in cinemas from 35 mm film prints. It has since also been used for TV broadcast, radio broadcast via satellite, digital video streaming, DVDs, Blu-ray discs and game consoles. Dolby AC-3 was the original version of the Dolby Digital codec. The basis of the Dolby AC-3 multi-channel audio coding standard is the modified discrete cosine transform (MDCT), a lossy audio compression algorithm. It is a modification of the discrete cosine transform (DCT) algorithm, which was proposed by Nasir Ahmed in 1972 for image compression. The DCT was adapted into the MDCT by J.P. Princen, A.W. Johnson and Alan B. Bradley at the University of Surrey in 1987. Dolby Laboratories adap ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Headroom (audio Signal Processing)
In digital and analog audio, headroom refers to the amount by which the signal-handling capabilities of an audio system can exceed a designated nominal level. Headroom can be thought of as a safety zone allowing transient audio peaks to exceed the nominal level without damaging the system or the audio signal, e.g., via clipping. Standards bodies differ in their recommendations for nominal level and headroom. Digital audio In digital audio, headroom is defined as the amount by which digital full scale (FS) exceeds the nominal level in decibels (dB). The European Broadcasting Union (EBU) specifies several nominal levels and resulting headroom for different applications. Analog audio In analog audio, headroom can mean low-level signal capabilities as well as the amount of extra power reserve available within the amplifiers that drive the loudspeakers. Alignment level Alignment level is an anchor point 9 dB below the nominal level, a reference level that exists th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
