Analog recording is a category of techniques used for the recording of analog signals. This enables later playback of the recorded analog audio.
Analog audio recording began with mechanical systems such as the phonautograph and phonograph. Later, electronic techniques such as wire and tape recording were developed.
A recording studio is a specialized facility for recording and mixing of instrumental or vocal musical performances, spoken words, and other sounds. They range in size from a small in-home project studio large enough to record a single singer-guitarist, to a large building with space for a full orchestra of 100 or more musicians. Ideally, both the recording and monitoring (listening and mixing) spaces are specially designed by an acoustician or audio engineer to achieve optimum acoustic properties (acoustic isolation or diffusion or absorption of reflected sound reverberation that could otherwise interfere with the sound heard by the listener).
Recording studios may be used to record singers, instrumental musicians (e.g., electric guitar, piano, saxophone, or ensembles such as orchestras), voice-over artists for advertisements or dialogue replacement in film, television, or animation, Foley, or to record their accompanying musical soundtracks. The typical recording studio consists of a room called the "studio" or "live room" equipped with microphones and mic stands, where instrumentalists and vocalists perform; and the "control room", where audio engineers, sometimes with record producers, as well, operate professional audio mixing consoles, effects units, or computers with specialized software suites to mix, manipulate (e.g., by adjusting the equalization and adding effects) and route the sound for analog or digital recording. The engineers and producers listen to the live music and the recorded "tracks" on high-quality monitor speakers or headphones.
Sound recording and reproduction is the electrical, mechanical, electronic, or digital inscription and re-creation of sound waves, such as spoken voice, singing, instrumental music, or sound effects. The two main classes of sound recording technology are analog recording and digital recording.
Acoustic analog recording is achieved by a microphone diaphragm that senses changes in atmospheric pressure caused by acoustic sound waves and records them as a mechanical representation of the sound waves on a medium such as a phonograph record (in which a stylus cuts grooves on a record). In magnetic tape recording, the sound waves vibrate the microphone diaphragm and are converted into a varying electric current, which is then converted to a varying magnetic field by an electromagnet, which makes a representation of the sound as magnetized areas on a plastic tape with a magnetic coating on it. Analog sound reproduction is the reverse process, with a larger loudspeaker diaphragm causing changes to atmospheric pressure to form acoustic sound waves.
An analog signal (American English) or analogue signal (British and Commonwealth English) is any signal, typically a continuous-time signal, representing some other quantity, i.e., analogous to another quantity. For example, in an analog audio signal, the instantaneous signal voltage varies in a manner analogous to the pressure of the sound waves.
In contrast, a digital signal represents the original time-varying quantity as a sampled sequence of quantized numeric values, typically but not necessarily in the form of a binary value. Digital sampling imposes some bandwidth and dynamic range constraints on the representation and adds quantization noise.
Analog devices are a combination of both analog machine and analog media that can together measure, record, reproduce, receive or broadcast continuous information, for example, the almost infinite number of grades of transparency, voltage, resistance, rotation, or pressure. In theory, the continuous information in an analog signal has an infinite number of possible values with the only limitation on resolution being the accuracy of the analog device.
Analog media are materials with analog properties, such as photographic film, which are used in analog devices, such as cameras.
Helical scan is a method of recording high-frequency signals on magnetic tape, used in open-reel video tape recorders, video cassette recorders, digital audio tape recorders, and some computer tape drives.
With this technique, magnetic tape heads (or head chips) are placed on a rotating head drum, which moves the chips at high speed by due to its high angular velocity. The speed of the head chips must be higher than the linear speed of the tape. The tape is wrapped tightly around the drum. The drum and/or the tape is tilted at an angle that allows the head chips to read the tape diagonally. The linear speed of the tape is slower than the speed of the head chips, allowing high frequency signals to be read or recorded, such as video. As the tape moves linearly or length-wise, the head chips move across the width of the tape in a diagonal path. Due to geometry, this allows for high head chip speeds, known as writing speeds, to be achieved in spite of the low linear speed of the tape. The high writing speed allows for high frequency signals to be recorded. As each head chip enters into contact with the tape, it creates or reads long and narrow areas with information recorded magnetically known as tracks. In Helical scan, these tracks are positioned diagonally, relative to the length of the tape. The diagonal tracks read or written using this method are known as helical tracks.