Although there have been numerous refinements to the technology, and other related technologies have been introduced (e.g. the electrostatic loudspeaker), the basic design and function of the dynamic loudspeaker has not changed substantially in 90 years, and it remains overwhelmingly the most common, sonically accurate and reliable means of converting electronic audio signals back into audible sound.
Although a number of short-lived "hybrid" studio and consumer technologies appeared in this period (e.g. Digital Audio Tape or DAT, which recorded digital signal samples onto standard magnetic tape), Sony assured the preeminence of its new digital recording system by introducing, together with Philips, the digital compact disc (CD). The compact disc rapidly replaced both the 12" album and the 7" single as the new standard consumer format, and ushered in a new era of high-fidelity consumer audio.
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Music streaming services have gained popularity since the late 2000s.[5] Streaming audio does not require the listener to own the audio files. Instead, they listen over the internet.[6] Streaming services offer an alternative method of consuming music and some follow a freemium business model. The freemium model many music streaming services use, such as Spotify and Apple Music, provide a limited amount of content for free, and then premium services for payment.[7] There are two categories in which streaming services are categorized, radio or on-demand. Streaming services such as Pandora use the radio model, allowing users to select playlists but not specific songs to listen to, while services such as Apple Music allow users to listen to both individual songs and pre-made playlists.[8]
Scott's early recordings languished in French archives until 2008 when scholars keen to resurrect the sounds captured in these and other types of early experimental recordings tracked them down. Rather than using rough 19th-century technology to create playable versions, they were scanned into a computer and software was used to convert their sound-modulated traces into digital audio files. Brief excerpts from two French songs and a recitation in Italian, all recorded in 1860, are the most substantial results.[9]
The advent of electrical recording in 1925 made it possible to use sensitive microphones to capture the sound and greatly improved the audio quality of records. A much wider range of frequencies could be recorded, the balance of high and low frequencies could be controlled by elementary electronic filters, and the signal could be amplified to the optimum level for driving the recording stylus. The leading record labels switched to the electrical process in 1925 and the rest soon followed, although one straggler in the US held out until 1929.
The wire is pulled rapidly across a recording head, which magnetizes each point along the wire in accordance with the intensity and polarity of the electrical audio signal being supplied to the recording head at that instant. By later drawing the wire across the same or a similar head while the head is not being supplied with an electrical signal, the varying magnetic field presented by the passing wire induces a similarly varying electric current in the head, recreating the original signal at a reduced level.
Magnetic recording was demonstrated in principle as early as 1898 by Valdemar Poulsen in his telegraphone. Magnetic wire recording, and its successor, magnetic tape recording, involve the use of a magnetized medium which moves with a constant speed past a recording head. An electrical signal, which is analogous to the sound that is to be recorded, is fed to the recording head, inducing a pattern of magnetization similar to the signal. A playback head can then pick up the changes in the magnetic field from the tape and convert it into an electrical signal.
Engineers at AEG, working with the chemical giant IG Farben, created the world's first practical magnetic tape recorder, the 'K1', which was first demonstrated in 1935. During World War II, an engineer at the Reichs-Rundfunk-Gesellschaft discovered the AC biasing technique. With this technique, an inaudible high-frequency signal, typically in the range of 50 to 150 kHz, is added to the audio signal before being applied to the recording head. Biasing radically improved the sound quality of magnetic tape recordings. By 1943 AEG had developed stereo tape recorders.
The next major development in the magnetic tape was multitrack recording, in which the tape is divided into multiple tracks parallel with each other. Because they are carried on the same medium, the tracks stay in perfect synchronization. The first development in multitracking was stereo sound, which divided the recording head into two tracks. First developed by German audio engineers ca. 1943, two-track recording was rapidly adopted for modern music in the 1950s because it enabled signals from two or more microphones to be recorded separately at the same time (while the use of several microphones to record on the same track had been common since the emergence of the electrical era in the 1920s), enabling stereophonic recordings to be made and edited conveniently. (The first stereo recordings, on disks, had been made in the 1930s, but were never issued commercially.) Stereo (either true, two-microphone stereo or multi mixed) quickly became the norm for commercial classical recordings and radio broadcasts, although many pop music and jazz recordings continued to be issued in monophonic sound until the mid-1960s.
By the late 1960s, disk reproducing equipment became so good that audiophiles soon became aware that some of the noise audible on recordings was not surface noise or deficiencies in their equipment, but reproduced tape hiss. A few specialist companies started making "direct to disc recordings", made by feeding microphone signals directly to a disk cutter (after amplification and mixing), in essence reverting to the pre-War direct method of recording. These recordings never became popular, but they dramatically demonstrated the magnitude and importance of the tape hiss problem.
In the 1970s, advances in solid-state electronics made the design and marketing of more sophisticated analog circuitry economically feasible. This led to a number of attempts to reduce tape hiss through the use of various forms of volume compression and expansion, the most notable and commercially successful being several systems developed by Dolby Laboratories. These systems divided the frequency spectrum into several bands and applied volume compression/expansion independently to each band (Engineers now often use the term "compansion" to refer to this process). The Dolby systems were very successful at increasing the effective dynamic range and signal-to-noise ratio of analog audio recording; to all intents and purposes, audible tape hiss could be eliminated. The original Dolby A was only used in professional recording. Successors found use in both professional and consumer formats; Dolby B became almost universal for prerecorded music on cassette. Subsequent forms, including Dolby C, (and the short-lived Dolby S) were developed for home use.
Magnetic soundtracks can be joined with the moving image but it creates an abrupt discontinuity because of the offset of the audio track relative to the picture. Whether optical or magnetic, the audio pickup must be located several inches ahead of the projection lamp, shutter and drive sprockets. There is usually a flywheel as well to smooth out the film moves to eliminate the flutter that would otherwise result from the negative pulldown mechanism. If you have films with a magnetic track, you should keep them away from strong magnetic sources, such as televisions. These can weaken or wipe the magnetic sound signal. Magnetic sound on a cellulose acetate film base is also more prone to vinegar syndrome than a film with just the image.[why?][citation needed]
In both cases, a light that is sent through the part of the film that corresponds to the soundtrack changes in intensity, proportional to the original sound, and that light is not projected on the screen but converted into an electrical signal by a light-sensitive device.
The first digital audio recorders were reel-to-reel decks introduced by companies such as Denon (1972), Soundstream (1979) and Mitsubishi. They used a digital technology known as PCM recording. Within a few years, however, many studios were using devices that encoded the digital audio data into a standard video signal, which was then recorded on a U-matic or other videotape recorder, using the rotating-head technology that was standard for video. A similar technology was used for a consumer format, Digital Audio Tape (DAT) which used rotating heads on a narrow tape contained in a cassette. DAT records at sampling rates of 48 kHz or 44.1 kHz, the latter being the same rate used on compact discs. Bit depth is 16 bits, also the same as compact discs. DAT was a failure in the consumer-audio field (too expensive, too finicky, and crippled by anti-copying regulations), but it became popular in studios (particularly home studios) and radio stations. A failed digital tape recording system was the Digital Compact Cassette (DCC).
The song known to United States Navy men and women as the "Navy Hymn," is a musical benediction that long has had a special appeal to seafaring men, particularly in the American Navy and the royal navies of the British Commonwealth and which, in more recent years, has become a part of French naval tradition.
Anchors Aweigh is the official fight song of the U.S. Naval Academy and is often heard at U.S. Navy events. The music was composed in 1906 by then-Lieutenant Charles Zimmermann, bandmaster of the United States Naval Academy Band. The lyrics were written by Midshipman First Class Alfred Hart Miles, USNA class of 1907.
The Library of Congress Celebrates the Songs of America The Songs of America online presentation explores American history through sound recordings, videos, sheet music and more. From popular and traditional songs, to poetic art songs and sacred music, the relationship of song to historical events from the nation's founding to the present is highlighted through more than 88,000 online items and is documented in the work of some of our country's greatest composers, scholars and performers. 2ff7e9595c
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