S : Side. The difference component of a stereo signal, i.e., the components which come from the side of the stereo field. See M & S.

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S & S : Sampling and Synthesis. A term used to describe synthesizers which combine elements of these processes to produce their sound.

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S-DAT : Stationary-head Digital Audio Tape. A bi-directional cassette tape designed for domestic digital recording. The head is stationary, as opposed to the rotating head of R-DAT. The tape speed is very low compared to professional stationary-head systems, such as DASH. The required data rate for stereo operation is achieved by distributing the 16-bit data over 20 data tracks in each direction. The sample rates are the same as for R-DAT, but 4-channel recording is possible at 32kHz with 12-bit nonlinear operation. S-DAT is not compatible with DCC as the latter does not conform to the S-DAT standard. See DAT.

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S-format : See C-format.

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S.R. : Senza Repeats, as in "play from the sign without repeats," written D.S. (S.R.).

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S/N : See signal-to-noise ratio.

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S/PDIF : Sony/Philips Digital Interface Format. A consumer standard, similar to the professional AES/EBU standard, (IEC-958) for encoding digital audio. Given the international standard number IEC-958, S/PDIF was originally designed to be the standard for transmitting audio data between CD players and DAT players, at a time when DAT was thought to be the next consumer audio recording medium.. The data transmission is the same as AES/EBU: four times the sample rate. S/PDIF Uses either standard unbalanced coaxial cable and phono jacks, or fibre optic cable and a connector called a Toslink, usually at -10dB. Note that the coaxis is not an RCA audio cable, but a video-grade cable: the impedance on this cable is 75Ω, and . Note also that S/PDIF carries the SCMS copy code. Both S/PDIF is a and its professional counterpart, AES/EBU, are self-clocking schemes. The EIAJ has adopted S/PDIF as CP-340 Type II.

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sabin : The efficiency with which materialsitems in a room absorbsoak up sound and damp down reverberation is measured in sabins, abbreviated Sa. The number of sabins of absorption is found by multiplying the number of square feet of a particular material by the absorption coefficient of that material. Also spelled sabine.

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Sabine equation : The reverberation time of a room is found using the Sabine equation:

 

                                                                                  RT60 = 0.049 X (V/Sa)

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SACD : Super Audio Compact Disc. Philips/Sony’s proposal for a next-generation CD which combines DVD technology to produce a hybrid disc that will play in conventional CD players, but offering better audio quality than currently available CDs when played in a DVD player. The upper later is the "conventional (Red Book) layer, while the lower layer provides around 4.7 Gb of high-density storage, increasing the audio capacity to 4.7Gb, the same as a first-generation DVD, and allow text, graphics, and video alongside audio. Audio will be encoded via either standard 16-bit PCM at 44.1kHz, or "Super Audio" using Sony’s DSD data format and Philips’ DST data compression technologies, yielding 74 minutes of six-channel audio with purportedly a frequency response of DC–1MHz and the same dynamic range as conventional digital recordings of 24–bit/96kHz resolution. SACD employs SBM noise-shaping, and PSP copy protection. The intention of the SACD standard is to ultimately combine a stereo DSD track and a six-channel DSD surround mix, plus optional data, text, graphics, and video data. Here is a comparison between conventional (Red Book) CD and (the current (3/99) prototype specification for) SACD:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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SACEM : Société des Auteurs, Compositeurs et Éditeurs de Musique. The French equivalent of BMI/ASCAP.

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safe mode : One of the operating modes of tape recorder electronics. Any tracks placed in safe mode are prevented from entering record mode, even if the engineer accidentally depresses the record-ready button or master-record button. Opposite of ready mode.

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safety : Short for safety copy or safety master, a duplicate of any audio or video tape made in case the master itself is lost or damaged. Also called a protection copy

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SAIT (Super AIT) : See, AIT

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sample : (1) A digitally recorded representation of a sound. Also, a single word of the data that makes up such a recording. Also called a patch or a program.

(2) To make a digital recording by taking regular measurements of the instantaneous voltage of an analog signal. See sampling.

(3) Any single measurement of such a voltage.

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sample (playback) synthesis : The production of a sound where a digital oscillator plays back a digitally sampled recording of an actual sound, such as a note played on a trumpet or guitar.

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sample-and-hold : The part of the A/D converter which actually does the job of sampling the signal. It measures the instantaneous signal voltage at a particular time and holds this level constant for the duration of the sampling interval as determined by the sampling rate. This level is meanwhile converted into a digital word before the sample-and-hold moves to the next sample. See aperture time errors.

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sampler : Essentially a digital recorder. An device that digitally records and plays back external sound sources, usually by allowing them to be distributed across a keyboard or other controller and played back at various pitches. Compare with synthesizer.

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sampling : The process of encoding an analog signal in digital form by reading (sampling) its level at precisely spaced intervals of time. See sample, sampling rate.

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sampling error : See jitter and aliasing.

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sampling rate : The rate at which PAM samples of an analog signal are encoded by a digital device. The higher the sampling rate during the encoding process, the greater the spectral bandwidth of signal it is able to record accurately. Typical sampling rates vary from 11kHz to 96kHz. The sampling rate for CDs is 44.1kHz. See sampling, Nyquist frequency. Sampling rates can be changed via a sampling rate converter, when the process is known as resampling.

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SAN Storage Area Network collections of initiators, such as servers or individual “workstations,” and use storage devices, typically desk- or tape-based, that are connected over a specialized or private LAN. The LAN can either have a copper or fiber PHY and usually employs either the ISCSI or FC protocols.

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SAOL : Structured Audio Orchestra Language. See MPEG-4. Together with SASBF these describe Wavetable syntheses. This is used in MPEG-4. A computer downloads and decodes structured Audio files containing samples, instrument definitions, and performance information. The decoded data is then used to re-create the music on the user’s system.

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SAP : Second Audio Program. A sub-channel used in multichannel television sound, often for second language programming.

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SAS (Serial-Attached SCSI) : a fundamental change to the seemingly evergreen SCSI standard that defines a shielded serial connection in place of the unshielded parallel connection of prior versions. As with SATA, another protocol originally a parallel approach, SAS provides higher throughput and higher reliability with reduced form factor and a lower overall cost when compared to the parallel version.

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SASBF : Structured Audio Sample Together with SAOL these describe Wavetable syntheses. This is used in MPEG-4. A computer downloads and decodes structured Audio files containing samples, instrument definitions, and performance information. The decoded data is then used to re-create the music on the user’s system.

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SATA Serial ATA. See ATA

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SATB : Soprano, Alto, Tenor and Bass.

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saturation : In analog magnetic tape recording, saturation is the maximum magnetization that a tape can attain. Actual recorded levels are less than saturation because saturation distortion is introduced if saturation is approached, especially at low frequencies. At high frequencies, it is not possible to reach tape saturation because the signal itself acts to partially erase itself as it is being recorded because the high-frequency signal causes the record head to act like a tape degausser. This is called self-erasure, and limits the maximum level attainable in a tape recorder at high frequencies. Distortion occurs in an analog tape recording caused by input levels set in excess of 0VU. Setting a record input level too high on an analog medium is more forgiving than on a digital medium, and levels up to +3VU can sometimes be tolerated, but with a corresponding loss of high frequencies. See overs, headroom, retentivity.

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saturation distortion : The distortion that results on magnetic recording tape when the applied audio signal is greater than its retentivity.

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saturation point : The input signal level to a tape recorder that will cause the record head to produce saturation on the magnetic tape.

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sawtooth wave : A geometrical waveform, typically generated by an oscillator, resembling a series of ramps. Sawtooth waves sound the same whether they rise left to right or fall left to right or a are series of alternating patterns (where the wave is sometimes called a ramp wave.) The sawtooth waveform contains all possible harmonics, both odd and even, giving a powerful and brassy timbre. The magnitude of each harmonic is the reciprocal of its number in the series, e.g., the fifth harmonic is 1/5 the amplitude of the first. See Appendix C.

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SBM : Super Bit-Mapping. See dither.

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scale : Music is made up of sounds pitched at relative intervals. The spacing of these intervals makes a scale. There are several principal modes each of which can be found by starting on the notes A-G and playing up the white notes (only) on a piano to the corresponding note an octave higher. They are Aeolian (A-A), Locrian (B-B, rare), Ionian (C-C), Dorian (D-D), Phrygian (E-E), Lydian (F-F), and Mixolydian (G-G). These can be transposed to start on different pitches as the interval pattern between notes is the essential feature.

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The modern major and minor scales correspond to the Ionian and Aeolian modes, respectively, and form the basis of most western music: (F=full-step, H=half-step, T=three half-steps)

 

 

 

 

 

 

 

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Within a scale, there is an ascending or descending series of notes that subdivide an octave into various and usually unequal pitch steps. The scales were collectively known as modes, and before about 1600 all were in common use. Between about 1600-1900 western music was centered on just two of the above scale patterns, the major and minor scales, which form the basis of diatonic harmony. Major and minor scales can begin on any note: those starting on C comprise the following notes:

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scale construction : See tonic and whole-step. For example, the relative minor of a major scale starts at either a sixth up or a third down on the major scale. To find the third, fourth, fifth, etc. of a tonic, count up that number of scale steps. For example, to find the sixth of a tonic, the major sixth would be nine half-steps above the tonic; the minor is diminished, i.e., it is eight half-steps above the tonic. The fifth is seven half-steps above the tonic or below it. A fourth is five half-steps above or below the tonic. The seventh is ten half-steps (minor) or eleven half-steps (major) above or below the tonic.

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scale distortion : Because the human ear has a sensitivity which varies with frequency and with loudness level, a musical ensemble must be reproduced at the same loudness as the listener would experience at the actual event if frequency distortion is not to occur. This happens because of the apparent amplitudes of the different frequencies will differ, with accentuation of the extreme high and low frequencies. Also called volume distortion. See equal loudness curves.

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scaling : In a synthesizer or sampler, a method of relating a parameter to a control so that the degree to which the control effects the parameter can be adjusted. For example, a pitch-bend wheel might be scaled to produce a half-step bend for a given amount of movement, or it might be scaled tot give a whole octave. Nonlinear scaling between control and parameter will produce an output corresponding to some sort of curve. If there is a point on the curve where the output changes radically in response to input, this is often called a breakpoint. The scaling of keyboard parameters is called keyboard tracking.

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scan : The way melody and lyrics are phrased together. A good scan means words and music fit well together and are easily sung and understood. Bad scan may occur when words such as "a" or "the" are sung on high notes or emphasized notes of the melody, sounding awkward or misphrased.

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Scheiber matrix encoding/decod : The algorithm used in Dolby Stereo optical process to produce quadraphonic LCRS(left/center/right/surround) sound from two channels. In this process, common in-phase information would bleed into the center channel, while the surround channel would receive out-of-phase material. See SVA.

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Schroeder diffusers : Used to construct ESS-type acoustic environments, aA structure comprising a number of wells of different, carefully-chosen depths. As a ray of sound strikes the irregular surface, instead of bounding off it like a mirror, it bounces out of each well at a slightly different time, resulting in many small reflections, spread out in both time and space. The operating range of a single diffuser is limited to about four octaves because, if the deepest well is deeper than about fifteen times its width, it begins to behave as a diaphragmatic absorber. The well depths are most commonly given by: where d is the depth of the diffuser, h is the well number, N is the prime number on which the sequence is based, and L is the wavelength of the lowest operating frequency. This is called the quadratic residue sequence.

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SCMS : Serial Copy Management System. A DAT format subcode which prevents direct digital copies by inserting a copy-protect message when a digital-to-digital copy of a recording is made. Once the flag is in the subcode of a tape, no subsequent copies can be made from that tape. SCMS is designed into most home digital recorders, and is a problem when transferring material from a consumer-type deck to a digital workstation or when trying to make safety copies of recording sessions. SCMS does not, however, prevent copies made using analog inputs. Some pro-level DAT decks include an SCMS defeat switch or use AES/EBU digital interfaces which are unaffected by the SCMS flags. Pronounced "scams" or "scums."

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scope : See anamorphic. Originally an abbreviation for CinemaScope™.

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score : (1) (noun) The original-music composition for a motion picture or television production, recorded after the picture has been edited.

(2) The conductor’s chart, containing all band parts of a musical arrangement, and the individual band parts.

(3) (verb) To write the music for a motion picture or television production soundtrack.

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scoring paper : Music paper with several (usually five) lines printed above each staff for other information needed by the composer while writing a score or jingle. These lines may contain elapsed time counts or SMPTE timecode addresses, summaries of on-screen action, dialogue and/or narration, required effects, etc.

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scoring stage : A large recording studio equipped with synchronous multitrack or other recording equipment, interlocked film and video playback, and large-screen projection in the studio itself. Motion pictures and video productions are scored here, the conductor watching the image and footage or SMPTE timecode data, and conducting performers so that the finished recording aligns properly with the footage.

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scoring wild : The recording of a motion picture or television score using non-synchronous recorders. The conductor defines timings for each part of the score from footage counts of the edited film, and seeks a performance that approximates the required timing to a close tolerance, perhaps one-half of a second. The wild score can be made to fit exactly if its playback speed can be adjusted during transfer, by editing in/out short pauses, etc. See also wild sound.

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scrape-flutter filter : In tape transports, a smooth or low-friction, non-magnetic, low-mass flywheel installed in the tape path in the order to minimize the pressure with which the tape meets guides, rollers, or other potential sources of scrape-flutter.

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scratch demo : A quick and inexpensive demo, usually done in a home studio, to give a client a rough idea of what type of music is being composed or produced under contract.

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scratching : A technique employed by some DJs, consisting of the rapid back and forth movement of a record turntable to cause the pick-up to produce the rhythmic scratching sound that is characteristic of rap and hip hop. This is done manually, with the turntable drive disengaged, or on a special turntable made for the purpose. Many records now feature scratching as an integral part of the recording process, and some CD players are now available with facilities for scratching and other effects.

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screen : (1) A panel with surfaces designed to reflect or absorb sound, used to alter the acoustic behavior of a recording space, or to isolate one performer from another.

(2) The shield part of a shielded cable. (3) A computer monitor.

 

scrub : To move backward and forward through an audio waveform under manual control in order to find a precise point in the wave for editing purposes.

 

SCSI : Small Computer System Interface. A bus specification standard used by personal computers to attach high-volume peripherals, such as mass storage devices, scanners, hard-disk recorders, etc. SCSI is a parallel data bus, and comes in several versions:

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SDDS : Sony Dynamic Digital Sound. Developed by Sony, the SDDS split-surround format uses the usual 5.1 stems, plus additional left-center and right-center channels. The additional two speakers are employed at the front of the soundstage to deliver more uniform sound in wide-format theaters of screen widths of up to 60’ or more, where there might be seats with a hole-in-the-middle in between the C-L, and C-R channels. An important aspect of the SDDS format is that it can be decoded into four, six, or eight channels for playback on a wide variety of audio systems. Proponents of this format claim that the extra front channels make a significant difference in the amount of depth, fullness and natural image of the audio.

See 7.1.

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SDII : Sound Designer II. The audio format native to Digidesign’s Sound Designer™ II (Macintosh) audio editing program. The original SoundDesigner format supports uncompressed, 16-bit mono sound files at several sampling rates. SDII supports 16-bit stereo files with sampling rates up to 48kHz; ADPCM compression is available at 2:1 and 4:1 ratios.

SDK German Traffic Information System.

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SDMI : Secure Digital Music Initiative. A working group formed by the RIAA to develop a "voluntary" method for protecting music copyright protection on the internet. SDMI is backed by the major labels, the aim of which is to simultaneously legitimize the distribution of music, while protecting copyright holders. There is an approximate analog in the UK with the name (Government’s) Creative Industries Taskforce (CIT).

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SDS : Sample Dump Standard. The MIDI standard used to transfer digital audio samples from one instrument to another over a MIDI cable. See SMDI.

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SDU4 : See DS4.

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sealed enclosure : The opposite of a ported enclosure. A loudspeaker cabinet with no vents or ports, e.g., an acoustic suspension system or an infinite baffle.

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search-to-cue : A feature in zero-locators that allows the engineer to instruct the recorder to find a designated time location on tape and stop there and await further instructions.

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second : The interval between one note and another, one half-step (minor second) or two half-steps (major second) above or below it.

See house sync, self null

See split feed. 

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segue : (1) An instantaneous switch from one musical selection to another without a gap; the absence of cross-fade. (2) Musical term meaning, "continue on without stopping." (3) A piece of music written to fill a gap, particularly in a musical or to link scenes in a film or TV program.

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SEL : Sound Exposure Level. The SEL of a noise event is the A-weighted SPL lasting one second that would have the same acoustic energy as the event itself. SEL is a way of comparing the noisiness of events that have different durations, such as airplane fly-over noise.

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sel-sync or sel synch : Selective synchronization. (1) In a multitrack tape recorder, the use of the record head to replay material from other tracks to be heard by the musicians while they overdub a new track. This is essential for accurate synchronization as the extra few milliseconds afforded by its position will compensate for the inevitable delay if the signal was taken from the main replay head which is some millimeters farther down in the tape stream. When the tracks of a multiple-track tape recording are recorded sequentially, one must listen to the previously recorded tracks while the current one is being recorded. If the standard playback head is used for this, there will be a time delay between the tracks when played back because of the physical distance between the recording and playback heads in the machine. To solve the problem, the record heads of the previously recorded tracks are used as playback heads while the adjacent tracks are being recorded. Since all the record head tracks are in line, there will be no delay. Also called simul-sync. Ampex has trademarked Sel-Sync,", but other products have similar features. . The replay quality is less good when using the record head for a function for which it was not designed, thus it is important that the recorder returns to monitoring from the main replay head during mixdown. See auto-input. (2) The process of recording new tracks on a multitrack tape while listening to previously recorded tracks via playback through other channels of the record head.(2) On a recorder used for synchronization of sound with motion pictures or videotape, a separate sync head that records and plays the sync tone or other sync signal.

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selectivity : The characteristic that describes the ability of a tuned circuit or a receiver to select the signal frequencies desired and reject all others.

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self-clocking : A device synchronization system whereby the clock information is embedded within the datastream, and the receiving device locks to it, as opposed to a master clock system. This system is not as stable as an internal clock as cables and network problems may introduce jitter. On professional systems, self-clocking protocols will be augmented with a master clock interface which sends word clock data.

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self-erasure : See saturation, HX/HX Pro.

 

self-noise : The intrinsic electrical noise or hiss produced by a microphone, measured in the absence of any input signal. Usually the self-noise specification is A-weighted: a self-noise figurespec of 18dB SPL or less is excellent, 28dB SPL is good, and over 35dB SPL is not good enough for quality recording. Dynamic mics have very low self-noise. The S/N ratio of a microphone is the difference in dB between the microphone’s sensitivity and its self-noise. See also reach.

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Selsyn motor : The trade name for a type of synchronous motor used to drive the projector, dubbers, and recorder in the dubbing, mixing, or re-recording theater. These motors, when connected to the generators and drive motors, will run in rigid interlock with one another, starting, running, slowing down, and running in reverse without loss of sync. See rock and roll.

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semi-parametric EQ : A semi-parametric equalizer control has two controls: frequency and boost/cut. A fully parametric band would allow the adjustment not only of the center frequency and the amount of cut or boost, but also the Q of the frequency band that is being affected.

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semitone : See half-step.

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sempre : Italian for "always," e.g., "sempre legato," always smoothly.

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send : An output on a recording or sound reinforcement console for a signal to be sent to another device, such as an equalizer or reverberator. The signal rejoins the chain at is returned to the console via the return connector. Typical consoles will have several sends and returns. See effects send.

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send level : A term used for both hardware audio mixers and software synthesizers, send level is the amount of a sound that is sent to an effects processor via the effects send.

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sensitivity : (1) The minimum required signal at the input of an audio device in order to produce the rated output is generally called the sensitivity of the device. The higher the sensitivity, the lower the signal required at the input. A device with high sensitivity can process very small signals, but may be distorted by large ones, whereas one with low sensitivity can process large signals without distortion, but may add an unacceptable level of noise to a small signal.

(2) In general, all information about a transducer’s response characteristics to incoming sound waves. With respect to microphones, a standard performance specification that indicates the output voltage generated when a sound of known SPL and frequency arrives at the diaphragm. Given in mV by most manufacturers, and generally specified for broadband response to pink noise. See efficiency, transfer characteristic.

(3) See velocity sensitivity.

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sensurround : A now-obsolete motion picture sound system which uses very strong, very low frequencies to simulate the effects of explosions, earthquakes, etc. It uses a special sound track on the film and separate amplifiers and high-power subwoofers to produce the effect. Originally, the first sensurround films simply triggered a noise generator during the scenes to have augmented LFE. Later versions recorded the very low-frequency on the print.

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sep mag : Separate magnetic film. Terminology for a print whose audio track is on a separate roll of mag film to be run in interlock with the picture; the same as double-system.

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separation : (1) In a multiple microphone set-up, the extent to which any one microphone is able to reject unwanted sounds intended to be picked up by other microphones. Separation is desirable if phase cancellation is to be avoided, and can be increased by careful microphone choice an placement. See directional microphone.

(2) The degree of isolation between signals flowing in two paths. Specified in decibels, indicating the level of a signal induced by one signal path in the other. See crosstalk.

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sequence : (1) A set of music performance commands (notes and controller data) stored by a sequencer. (2) To edit the master tapes of an album, putting the songs in the desired order, prior to cutting acetates and lacquer masters, etc.

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sequencer : A device or program that records and plays back user-determined sets of music performance commands, usually in the form of MIDI data. Most sequencers also allow the data to be edited in various ways and stored on disk.

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sequential monaural : A single bit stream read from a CD is a really one-channel serial datastream, with time-division multiplexing used to interlace the left and right audio channels. See CD-ROM

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serial : (1) Data transmission whereby all bits are sent one after the other, as opposed to using a parallel interface where bits are sent in groups. Parallel protocols are more complex than serial and the and the connectors are more complicated and , hence, more expensive, all of which makes it. It’s also harder easier to get the specification implemented correctly wrong among vendors., For this reason,hence, MIDI uses a serial transmission protocol and specifies a serial interface, even though the transmission time required is substantially higher than for a parallel protocol. As MIDI files are quite small, compared with files which contain actual audio or video content, the relative lack of transmission speed was felt to be a good trade-off for the simplicity of its implementation..

(2) Network connections where devices in the network are hooked up in a line, i.e., one to the next. This is called a daisy-chain, and is the opposite of a parallel topology.

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serial interface : A hardware interface which transmitsmeans of outputting computer data using a serial protocol whereby all bits in a digital word are sent one after the other. This is generally cheaper than using a parallel interface as the connectors need only one transmit pin and one receive pin, plus ground. However, the time taken to transmit each word is greater than for a parallel data; the MIDI specification calls for a serial hardware interface, i.e., it is a serial protocol interface.

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serial port : A connector on a Mac which is used to connect devices which use a serial interface, such as some MIDI interfaces, and printers.

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servo : Short for servomechanism. A control system that uses feedback from an output signal to compare to a reference signal. The difference between the two is an error signal, which is used to change the output signal in such as way as to reduce the error. Used to control speeds in tape recorders and turntables and to position the laser beam in CD players. Negative feedback in an amplifier is an example of an electronic servo.

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session tape : The original recording made during a live playing session.

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Set- Up : A Universal System-Exclusive message of the non-real-time type which defines a list of events which are to be carried out a given MTC times by the receiving device, such as event name, start and stop times, plus effect parameters.

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set-up : (1) The part of a recording session in which the engineer places various instrumentalists or vocalists, sets up the microphones, and gets basic sounds through the recording console.

(2) The program chain.

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SEU4 : See DS4.

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seventh : The interval between a note and another that is seven scale steps above or below it. This will be either ten half-steps (minor seventh) or eleven half-steps (major seventh).

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SFI : A file extension specifying Turtle Beach’s SoundStage™ audio format. Typically encountered as FILENAME.SFI.

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sfx : Sound effects.

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Shannon’s channel capacity :The formula, DRmax=W log 2 (1+sn) , where DR is data rate, W is channel bandwidth, and SN is the S/N ratio. It expresses the relationship between these three variables in digital audio.

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sharp : (1) Higher in pitch, as opposed to flat. In reference to musical scales, sharp (A) indicates one half-step higher. (2) In filters, sharp refers to the rapidity with which the response of the filter falls off in the filter stopband, synonymous with rolloff slope. In general, the sharper the filter, the greater its phase-shift. See also FIR.

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shelving EQ : A typical layout for semi-pro mixers provides low- and high-shelving equalization from a pair of knobs labeled "bass" and "treble" and one semi-parametric midrange band. The low and high EQ are called shelving because a graph of their response curve looks somewhat like a drawing of a shelf. Any portion of the tone above (in the case of treble EQ) or below (in the case of bass EQ) a factory-preset is boosted or attenuated.

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shielded cable : One or more insulated wires covered by a wrapped or braided metal shield. The wires carry the electricity, while the shield acts as an EMI barrier to the audio signals. See balanced line.

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shock mount : A microphone suspension system that prevents mechanical vibrations of the stand from reaching the mic. Usually made of elastic bands mounted on a metal frame, which together hold the mic in position without rigid mechanical contact with the stand.

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shoot : In film, slang for recording. It is derived from the previous use of optical sound in all film sound recording, i.e., sound recorded on film.

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short circuit : A circuit in which some unplanned event, such as the failure of a component or a stray piece of metal bridging two live contacts, has reduced the resistance in the circuit, resulting in increased current flow through the circuit. It can be said that a complete short circuit has zero resistance and consequently infinite current flow, however, AC line voltage will limit this to either 120V or 240V, which is plenty of current by which to get dead. In anticipation of these accidents, most devices have fuses or other componentry integral to the device and/or its power supply which are designed to fail, breaking the circuit, in the presence of abnormally high voltage.

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shortcut : A file on a PC-type computer that is similar to the Mac’s alias feature.

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shotgun microphone : See gun microphone.

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shuttle : To wind the tape on a tape recorder back and forth in order to locate a specific audio event selection.

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SI : Système Internationale. The international measurement standard known as "metric," as in SI Units. See watt.

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sibilance : The high-pitched whistling caused by air passing around the teeth, such as is produced by saying certain letters: f, s, t, x, or soft-c. Most sibilance occurs in the 5-10kHz region. See de-esser.

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Side : (1) Any master tape of one song, whether recorded for inclusion in an album, or as the A- or B-SB side of a single. Always capitalized, Side is used in recording contracts, so precise definition is important.

(2) In the AFTRA Code of Fair Practice, a Side is a master tape of no more than 3 1/2 minutes. If the total length of the song is longer than that, AFTRA singers receive additional payment.

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side chain : A circuit which measures how strong the input signal is which is being modulated by a compressor. This information is then used to control the gain of the circuit output. The compressor will behave differently, depending on whether the side chain responds to average signal levels or to absolute signal peaks. In the example below, for Dolby B-type companding, the side chain feeds any signals above 3kHz to the compressor:

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side-addressed : See end-addressed

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sidebands : (1) Frequency components outside the natural harmonic series, generally introduced to the tone by using an audio-range wave for modulation. See AM,FM.

(2) Elements of a high-frequency carrier signal created when the data/voice signal is modulated with the carrier signal, as in FM synthesis. The new sets of partials generated by the modulated carrier give the tones the timbre other than that of the original sine wave.

 

sign (Signo) : A musical symbol (D) indicating a particular place in the music, e.g., D.S. (Dal Signo), meaning "play from the sign." D.S. (S.R.) means "play from the sign without repeats," and D.S. (C.R.) means "play from the sign with repeats."

 

signal : (1) The desired portion of electrical information, i.e., the information content of any transmission medium, i.e., the part of the waveform that is not noise.

(2) A generic name for any one of a number of forms (magnetic orientation, voltage) which audio may take in the program chain.

 

signal entropy : A condition caused by audio data which is characterized by frequent transienttransients, causing a compression algorithm to poorly encode data. If the signal is compressed before encoding, the data compression will be much more effective, with less effect on the audio. Signal entropy is not a problem for ADPCM-type compression algorithms.

 

signal generator : A test instrument that produces one or more of the following types of waveforms through a wide range of frequencies: sine wave, square wave, sawtooth, ramp voltage, etc. See Appendix C.

 

signal ground : Each component of a sound system produces its own internal ground. This is called the audio signal ground of the device. Connecting devices together with cables can tie the signal grounds of the units together in one place through the conductors in the cable. See ground loops, chassis ground.

 

signal processing : The modulation of an audio signal in a generally desirable way by any device inserted into the audio chain path.

 

signal processor : See processor.

Signal to Noise Ratio indicates how much irritating background hiss is produced as a proportion of the full output power. Numbers higher than 90dB are acceptable and the higher the better. A good indicator of the quality of the amplifier.

 

simple time : See time signature.

 

simul-sync : See sel-sync.

 

simulDAT : A DAT recording made during a Telecine transfer in which the production audio is transferred to a DAT whose timecode matches that of the videotape.

 

sine wave : The waveform of a pure alternating current or voltage. It deviates about a zero point to a positive value and a negative value, consists of a single frequency and has a musical pitch, but a neutral timbre. Audio-range sine waves contain only the fundamental frequency, with no overtones and form the building-blocks for more complex sounds which are combinations of sine waves. Sub-audio sine waves are used by an LFO to modulate other waveforms to produce vibrato and tremolo. Also called a sinusoid. See Fourier analysis.

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Single Note Retuning Message : A Universal System-Exclusive (SyEx) message of the real-time type which is intended to provide a performance control over the tuning of an individual note.

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single-ended noise reduction : Single-ended NR systems work on playback only. Analog systems work by combining dynamic filters with low-level expanders so that the signal level decays, high frequencies are progressively filtered out. At very low levels, the expander acts as a soft gate to clean up pauses. Digital systems are more complicated and use a split-band expander. See noise reduction.

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single-stripe : Magnetic film which is coated with oxide, containing a single audio track.

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single-system sound : A way of producing sound for motion pictures where the sound is recorded directly onto the film in the camera at the time of shooting. Sound and picture are thus on a single strip of film from the start, with image and sound in projection sync with each other. Used primarily for news and sports where the relatively limited-fidelity of single system cameras can be tolerated. Cheaper than double-system sound, but also less flexible. Video is, by definition, single-system sound, but may be used as a double-system if a separate audio recorder is used during filming.

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six-channel mix : A nomenclature used for an audio-only surround-sound mix, more generally referred to as 5.1 which can refer to either audio-only or audio-for-video.

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six-mix : See six-channel mix,5.1.

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sixth : The interval between a note and the one six scale steps above or below: either eight half-steps (minor sixth) or nine half-steps (major sixth).

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skew : A deflection or dislocation of the proper path for magnetic tape as it passes over a misaligned tape head, guide, or

roller.

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slap echo : The single repetition of a signal at a fixed time delay to simulate an echo from a single reflecting surface, as opposed to a multiple echo from a time delay, where the delayed signal is repeatedly fed back into the delay input. The sound is repeated once or twice only, with a short delay of 40-60ms.

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slapback : (1) An unwanted and distracting echo caused by a reflective surface in any environment, e.g., a large window in a recording studio, a cement wall at a concert venue.

(2) A tape delay and the slap echo it creates. See delay line

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slate : To identify the various takes in a recording session by announcing the take numbers and recording them on one track of the tape. Slating and the notes taken at the time of recording are important once tape editing begins, otherwise it would be almost impossible to find any particular take.

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slave : An audiotape or videotape transport, motion picture projector, magnetic film recorder or dubber whose movements follow the movement of a single master transport, accomplished electronically by using, for example, SMPTE time code, or electromechanically by linkage of sprocketed machine motors to provide identical movement of all sprocket drives.

slew limiting : The effect which occurs when the input signal amplitude would require the output to change faster than the maximum slew rate of the device.

 

slew rate : Slew rate is a common specification for transient behavior of electronic devices. It is expressed in V/µs and tells how fast the output of the device rises, given a rapidly rising input. A slew rate of 40V/µs means that it would take one µs for the output to change by 40V. Since studio equipment typically operates on +15V and -15V internally, its output can never really swing 40V. In reality, it might gto 5V in 1/8µs. An audio device will have a maximum slew rate above which it cannot operate. This maximum limits the high-frequency power output of amplifiers and limits the high-level, high-frequency handling capacity in all audio devices. Too low a maximum slew rate results in slew-induced distortion, called transient intermodulation distortion (TIM).

 

slip cue : In playing records, the process of locating the first note of music in any band, holding the disc motionless while the turntable rotates beneath it, then releasing the record so that music begins precisely when the disc is released. This is done either to effect precise segues, or to align the rhythm of one record with another one already playing, called mixing.

 

slop print : See workprint. Also called a dirty dupe or scratch print.

 

slope : See rolloff slope.

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small signal bandwidth : The bandwidth an audio device will exhibit at relatively low signal levels. Most audio devices will have a wider frequency range at low signal levels than high signal levels because of such effects as slew limiting. See power bandwidth.

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small-room X-Curve : See X-Curve.

 

smart slate : Timecode slate that contains a timecode generator. A "dumb" slate must be fed timecode continuously.

 

smart sync : The ability of some A/D-D/A converters, digital recorders, or other digital devices to automatically sync to word clock.

 

SMDI : SCSI Musical Data Interchange. A specification for sending MIDI sample dumps over the SCSI bus. This requires that the computer be connected to a sampler via both SCSI and MIDI interfaces. See SDS.

 

SMF : Standard MIDI File. A file format For transferring data between sequencers and between Macs and PCs. Sequence data is stored on disk in one of three formats: Type 0 packages all data into a single track, regardless of the number of original tracks. Type 1 retains the track layout, although the tempo and time signature of all tracks will be those of track one. Type 2 is the same as Type 1, except that each track keeps its own tempo and time signature, but is seldom implemented. The files include information called meta events about such things as track and instrument names, copyright notice, tempo change, SMPTE timecode offset, lyrics and key and time signatures. The time between sequence events is encoded in delta time messages of between one and four bytes.

 

SMP : Turtle Beach’s SampleVision™ audio file format. Typically encountered as FILENAME.SMP.

 

SMPTE : Society of Motion Picture and Television Engineers. Also used as an abbreviation for SMPTE timecode.

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SMPTE curve : An equalization curve standard in the U.S. for 35mm mag film.

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SMPTE leader : See SMPTE Universal leader.

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SMPTE sync track : A square wave recorded onto an audio track. Note that this is only possible with digital audio, so for the most reliable results when transferring audio, use jam sync. See also sync track.

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SMPTE timecode time code: A high-frequency timing reference signal developed by by the Society of Motion Picture and Television Engineers and used for synchronizing film and videotape to audio tape and software-based playback systems. SMPTE is a tempo-independent code which comprises a continuous stream of absolute positional data, so if a short section of code gets lost or corrupted, the system knows exactly where it’s supposed to be the next time a piece of valid code is read. Usually generated at the picture source, i.e., the SMPTE master clock generator that drives the film or television camera system, the signal is recorded onto the videotape or along the edge of the motion picture film, and sent simultaneously to the audio recorder. The signal contains encoded numerical information, allowing the same point in film or tape time to be located on the separate strips of film/videotape and audio tape, for proper alignment or ADR. The playback operator can select a SMPTE timecode number that instructs videotape and audiotape machines to locate a certain point and begin playing in sync from that absolute location. TimecodeTime code data are in the form of a timecodetime code address (TCA), which make up the HH:MM:SS:FF part of the timecodetime code word, where HH is a two-byte number for absolute time hour, MM is minutes, SS is seconds, and FF denotes the absolute frame number. See frame, jam sync, LTC, MTC, BITC, VITC., and bi-phase modulation. Also called longitudinal timecodetime code. As opposed to speed-only sync codes such as pilot tone, FSK, and DIN sync.

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SMPTE Universal leader : Designed primarily for video, the leader, after Picture Start, features a sweep hand counting down from eight seconds. See Academy leader.

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snake : An assembly of cables or wires, often used to carry several channels of audio signals between two points, such as from the stage to a mixer. The most commonly used sn makes consist of several sets of balanced line connections, with a snake box at the mic end, fitted with the appropriate number of XLR-type microphone sockets, the long, large, multiwire cable on which the individual channels are carried, terminating in a large modular connector for connection to a distribution panel which is, in turn, connected to a power amplifier or preamp. Also called multicore or rope. A snake box is also called a stage box.

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snake box : See snake.

 

snake track : A special optical sound track on a test film for adjusting the alignment of the optical sound system in a motion picture projector equipped to reproduce SVA sound tracks.

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snapshot automation : A form of MIDI-controlled mixing automation in which the controlling device records the instantaneous settings (the snapshot) for all levels and panpots, and recalls these settings on cue.

 

SND : See SouND resource.

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SNR : See signal-to-noise ratio.

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soft clipping : A form of clipping where the edges of the clipped waveform are rounded rather than sharp. Soft clipping is much easier on the ears and tweeters than hard, as it contains much less very high frequency energy. Compare with hard clipping.

 

soft knee compression : The output of a compressor whose gain reduction is brought in progressively over a range of input signal values, such as over 10db or so, starting a few dBs below the threshold.. When the input signal amplitude comes within the range of the threshold, the compressor starts to apply again reduction, but with a very low ratio setting. As the input level increases, the compression is automatically increased until, at the threshold level, the ratio becomes infinite. Compare with hard knee compression.