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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. Sound ... [...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 signals. Audio signals have frequencies in the audio frequency range of roughly 20 to 20,000 Hz, which corresponds to the lower and upper limits of human hearing. Audio signals may be synthesized directly, or may originate at a transducer such as a microphone, 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 storage device or mixing console, used in operations such as multi-track recording and sound reinforcement. Signal flow Signal flow is the path an audio signal will take from source to the sp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
U-571 (film)
''U-571'' is a 2000 submarine film directed by Jonathan Mostow from a screenplay he co-wrote with Sam Montgomery and David Ayer. The film stars Matthew McConaughey, Harvey Keitel, Bill Paxton, Jon Bon Jovi, Jake Weber and Matthew Settle. The film, telling the story of a World War II German submarine boarded by American submariners to capture her Enigma cipher machine, does not represent any real events. Although the film was financially successful and reasonably well received by critics, and won the Academy Award for Best Sound Editing, the plot attracted substantial criticism. British sailors from captured the first naval Enigma machine from in the North Atlantic in May 1941, months before the United States entered the war and three years before the US Navy captured and its Enigma machine. Anger over these inaccuracies reached the House of Commons, where the Prime Minister, Tony Blair, agreed that the film was an "affront" to British sailors. The film was also criticized for ... [...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 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 des ... (LFE) channel. However, when there is no subwoofer, the bass manager directs the L ... [...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 coi ... [...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 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 des ... (LFE) channel. However, when there is no subwoofer, the bass manager directs the L ... [...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 "Sound Bar," 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 experience of home cinema, even if they do not want to-or do not have the electronics "know-how" to pick out all of the components one-by-one and connect the cables. If a consumer were to buy all of the items individually, they would have to have a basic knowledge of electronic ... [...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. Dolby Stereo (also known as ''Dolby MP'' or ''Dolby SVA'') 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 ''"Dolby Surround"'' on home video. However, the original Dolby Surround decoders in 1982 were a simple passive matrix three-channel decoder: L/R and Mono Surround. The surround was limit ... [...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. Dolby Stereo (also known as ''Dolby MP'' or ''Dolby SVA'') 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 ''"Dolby Surround"'' on home video. However, the original Dolby Surround decoders in 1982 were a simple passive matrix three-channel decoder: L/R and Mono Surround. The surround was limite ... [...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 sp ... [...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 strips, 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, with an aspect ratio of 2.2:1. However, the use of anamorphic Ultra Panavision 70 lenses squeezes the image into an ultra-wide 2.76:1 aspect ratio. To this day, Ultra Panavision 70 produces the widest picture size in the history of filmmaking; surpassed only by Polyvision, which was only used for 1927's Napoleon. With regard to exhibition, 70 mm fil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dolby Digital
Dolby Digital, originally synonymous with Dolby AC-3, is the name for what has now become a family of audio compression technologies developed by Dolby Laboratories. Formerly named Dolby Stereo Digital until 1995, the audio compression is lossy (except for Dolby TrueHD), based on the modified discrete cosine transform (MDCT) algorithm. The first use of Dolby Digital was to provide digital sound in cinemas from 35 mm film prints; today, it is also used for applications such as TV broadcast, radio broadcast via satellite, digital video streaming, DVDs, Blu-ray discs and game consoles. The main 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 first proposed by Nasir Ahmed in 1972 and was originally intended for image compression. The DCT was adapted into the modified discrete cosine transform (MD ... [...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 throu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
