Sound recording and reproduction

When recording or sound recording in the narrow, technical sense, it refers to the recording and reproduction of sound, so noise, sounds, music and speech with audio recorders. It is characterized by the separation of the recording, storage and playback method and can be mechanically ( grooves in rolls, records or other suitable solids ), magnetic ( tape), optical ( optical sound from movies ) or also digital, the latter on magnetic ( floppy disk, hard disk, DAT ) or optical (CD, DVD) media or on immovable digital memory ( read-only memory, ROM).

• 4.1 Stereofizierung of mono recordings

• 5.1 Analog storage
• 5.2 Digital storage

Demarcation

In some publications, in particular, to microphones, it is said that a noise event " removed " is ("This microphone is well suited for miking guitar ..."). This is not correct, because microphones are located in a sound field, ie in an environment that is generated in the air by the sound generator compressions and dilutions, which follows the effective portion of the microphone and converts it into electrical signals amplifiable.

The acceptance of a sound event, however, is possible at the sound generator without going through the air just right (in contact ). A pickup, today usually based on piezoelectric crystals, the vibrations of a solid body is able to walk directly into electrical signals ( phonograph cartridges, laryngeal microphones, acoustic emission sensor ). In contrast, systems that convert mechanical vibrations of a solid body about coils and magnets into electrical signals, also known as Pickup ( guitar pick- ups).

Music recording is technically generated presentation of a musical performance. It follows its own musical and aesthetic laws. The music recording is a technical treatment of the sonic event. The recording embodies so an independent aesthetic artifact that is no longer reproducible in live performances. It sets the standard to which every musical performance, will consciously or unconsciously, is measured.

Music production, however, is a construction technique in which result media -bound musical events arise that represent not only independent aesthetic artifacts, but are shaped by technology mediated aesthetic dimensions which themselves do not know the performance practice, this has not even left unchanged.

History

The oldest surviving audio recording (in the broadest sense) is from the year 1860. Édouard -Léon Scott de Martinville was a attached to a membrane pig bristle on a rotating, blackened drum vibrate. Its graphical recording machine vibrations he called Phonautograph. The inventor wanted " show " as sound vibrations look like. At a use of this in the literal sense " recorded " vibrations for sound reproduction has not been thought at the time, 2008, it was through the use of computer technology but possible.

The next most recent recordings, but they were now also intended for playback and marketing are that of Thomas Alva Edison in the year 1877. He called his invention the phonograph. His devices were initially intended mainly as voice recorders. But soon recorded with music rolls were sold. Yet his rugged devices were always equally intended for recording and playback, and therefore served a long time for researchers (especially anthropologists ) and artists as well as private individuals for their own recordings.

Thomas Edison sent his " Perfected Phonograph " to George Gouraud in London, and on August 14, 1888 made ​​this the machine London in a press conference. He also played a recording of a piece for piano and cornet from Arthur Sullivan's "The Lost Chord ". This was and is one of the oldest surviving musical recordings. A series of presentations followed, in which the unit members of society in "Little Menlo " in London was shown. Sullivan was invited on October 5, 1888. After dinner he took with the device a little speech to send it to Edison. In it, he said among other things:

"I can only say I am astonished and did somewhat terrified at the result of this evening 's experiments: astonished at the wonderful power you have developed, and terrified at the thought did so much hideous and bad music 'may be put on record forever. But all the same I think it is the most wonderful thing did I have ever experienced, and I congratulate you with all my heart on this wonderful discovery. "

These recordings were discovered in the 1950s in the Edison Library in New Jersey.

The German Americans Emil Berliner developed the gramophone ( patent 1887) and the record. While Edison cylinders had to be originally recorded time consuming individually, the records could be very cost- pressed in crowds. The commercially sold gramophones were therefore designed from the outset for playback only and could be significantly less complex construction and therefore produced more favorable. Another difference was that the sounds were represented by lateral curves of the record groove at Berliner's system and to date in all records (so -called side or Berlin font), while Edison was digging the sound waves in the depth of the groove ( so-called depth or Edison font). The latter variant was forgotten for a long time, but has been taken up much later for digital recording on the CDs.

Both of these and related early systems (particularly the roller system of the Frenchman Henri Lioret, who first used celluloid for his phonograms, and the somewhat later disk systems of Edison and the French company Pathé Frères ) is usually under the term acoustic sound recording together because they completely do without electricity. This term is misleading, however, because the acoustics are always involved when it comes to sound. The essential characteristic of these systems, however, is that the sound is converted into vibrations of a membrane, which is then stored in a purely mechanical way and reproduced. The total energy required for this purpose must muster even the sound. Thus, the sound quality ( frequency range and balance of reproduced sounds ) and volume are set narrow limits, the expanded throughout history, but never even could be eliminated to some extent. This allowed only the electricity and later the electronics. The " acoustic " sound recording was also used to show off by mechanical coupling of the phonograph or gramophone with a film projector, the first sound films. In the area of film technology we speak of Nadelton process. However, the early attempts in this direction, such as Edison or the German film pioneer Oskar Messter failed even to the limited volume.

The electromagnetic sound recording as the first electricity -use method was invented by the Danish telephone engineer Valdemar Poulsen in 1898. His imaginary mainly at the beginning of the recording of telephone conversations device he called telegraphone. Media was in the original construction, a wire which was laid helically on the outside of a roll. About this slipped a U-shaped Magnettonkopf on a rail back and forth and it included the wire. To the electromagnet of the magnetic head was connected to a telephone handset. When recording of the induced current generated in a magnetic field generated microphone in the wire, which then generated electric current in the head in the reproduction, which corresponded to the sound, and was performed on the receiver as such. A later design of this device used a metal tape on two reels and got away with it in appearance have the tape recorder close to the AEG introduced under the name of " tape recorder " in 1935. Meanwhile plastic recordings were at BASF on the basis of an earlier, from paper strip existing system has been developed.

From about 1963, several companies significantly reduced equipment brought out that no longer aufwickelten the tape on open reels but in cassettes. That facilitates the handling and storage considerably. Because very liberal licensing to the Philips system ( Compact Cassette, CC) prevailed worldwide. In this case, a tape including two coil is encapsulated in a plastic package for easy handling. Colloquially, the CC is often called simply " cassette" or " tape". Already prerecorded cassettes are sold as cassette tapes or music cassette (MC ) refers. The playing and recording cassettes made ​​with a cassette recorder. As a further development of the electromagnetic sound recording from around 1960 to also succeeded in electromagnetic imaging ( in the jargon of television technology magnetic recording ( VTR ) and video technology called in the private sector ). Furthermore, the digital data storage is based on this electromagnetic technology.

Today's admission process

The sound recording is a technical process, converted at the acoustic oscillations in all present-day processes into electrical signals and then in analog or digital form (electromagnetic analog recording or digital recording ) can be stored on storage media. The oscillation of the sound is always recorded; that is - in scientific terms - the sound pressure change as variation of the amplitude (voltage value ) on the time axis.

If several sound recordings that occurred temporally independently, are later played synchronously in time, a time code is recorded either together with the signal and synchronizes the signals based on the time stamp, or it is a multi-track recording on a common Media created.

Multi-track recording

In this method, sound recordings or in succession created simultaneously with a multi-track recorder on a medium, with the individual shots are recorded but in so-called traces separately. Thus, the recordings can be edited in the recording studio separated from each other in many ways.

Will the images of the individual tracks sequentially created and added copied each other, one speaks of the overdubbing process.

Single -track recording

Notwithstanding the multi-track recording multi-channel audio signals in this case the are mixed together without caching directly to the so-called sum signal. The result is there as a finished stereo tracks or surround tracks.

One advantage is that due to the elimination of caching a higher sound quality can be achieved, but this is largely obsolete for digital storage. In addition, the technical complexity compared to a multi-track recording is a bit lower, as the recording devices and their interconnection is much easier. The disadvantage is that one loses much flexibility in recording. It is limited to the possibilities that exist when mastering. In the field of conservative recordings in which the finished stereo sums must be made ​​for the sake of assessing the mix anyway, 2- channel recordings are still typical.

Stereo recordings

Apart from surround recordings most shots are made in stereo technology since the mid- 1950s, when the means of different stereo recording process a 2-channel electrical signal is generated which - played through a stereo triangle - reflects the sound scene on the stereo base between the two speakers.

Predominantly mono recordings were made before 1960.

Stereofizierung of mono recordings

From a mono recording a Pseudostereofonieaufnahme can produce, while the original mono signal must be destroyed without. This is also called "electronic Stereo" (see Pseudostereofonie ). Of particular importance getting the original mono signal is at historical sources.

Storage method

Analog storage

With analog recording the signals obtained from the microphones are each translated by a carrier medium in other analogous vibrations, such as alternating strong magnetization of the write head of a tape evenly over -run tape. This time is stored in the movement of the tape. The analog voice memo is subject to typical artifacts such as additional noise, distortion or dynamic limitations.

Digital storage

Digital recording means that the signal source, either already itself been digitally (for example, digital synthesizer ) or that analog audio signals that are received, for example, microphones, are digitized in the signal chain by means of an analog / digital converter.

The digital recording omitted og additional noise that would be incurred in an analog recording in the re-sampling of the medium ( eg, tape noise, scratching records ). On the other hand, the quality of the recording is decisively determined by digitization. Therefore, one chooses some higher sampling rates and / or a higher word length per sample, as for example on an audio CD would actually be later necessary for the reproduction of this step. The product of the sampling rate and word length is also called bit rate.