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S.P.L. : - Sound Pressure Level, measured in Decibels (dB's).

S/PDIF -- Acronym for "Sony/Philips Digital Inter Face". [ Also sometimes referred to by its common "standards" title of IEC958 (type-2). It also conforms with the EIAJ standard of CP-340 (type-2), now renumbered to CP-1201 ].
SAFETY COPY: Copy or clone of an original tape for use in case of loss or damage to the original.

Sample - a sound or short piece of audio stored digitally in a computer, synthesizer or sampler. The word sample may refer to either a single moment in a digital audio stream (the smallest piece of data used to represent an audio signal at a given time) or a complete sound or digital audio stream made up of a collection of individual samples. For a more detailed explanation of samples, see Digital Audio Basics.

SAMPLE AND HOLD: Usually refers to a feature whereby random values are generated at regular intervals and then used to control another function such as pitch or filter frequency. Sample and hold circuits were also used in old analogue synthesizers to 'remember' the note being played after a key had been released.

Sample Rate - the resolution of digital audio that determines it's sound quality. When audio is digitally recorded (digitized), it must be converted into a series of samples which can be stored in memory or on disk. The sample rate defines how many samples are recorded per second of audio input and is measured in Hz (Hertz, cycles per second) and kHz (Kilohertz, thousand cycles per second). Click the examples below to hear the difference between a few commonly used sample rates. The rate at which samples of a waveform are made. Must be twice the highest frequency one wishes to capture. Commercial compact discs use a rate of 44,100 samples per second. is the rate at which samples of a waveform are made and must be twice the highest frequency one wishes to capture. Commercial compact discs use a rate of 44,100 samples per second. When audio is digitized, the sampling rate is the number of "pictures taken" in a second. A high sample rate means that the resolution of the recording is high, thus very "accurate". Most common sample rates in professional recording are 44.1Khz and 48Khz.

Sample: - When a sound is converted from analogue to digital format, the amplitude of the signal is sliced into many segments of binary information and analysed, these slices are measured per second (for a standard audio C.D. this is carried out 44,100 times) thus we may say that a C.D. has a "sample rate" of "44.1khz". Rather like the "pixels" of a visual image, the more "samples" taken per second, the higher the resultant sound quality. A digital "snippet" of a sound, which can be triggered by a MIDI keyboard. Can be a drum sound, orchestral sound or vocal phrase. A digital recording of a naturally occurring sound. A digitized sound used as a musical sound source in a sampler or additive synthesizer. The process carried out by an A/D converter where the instantaneous amplitude of a signal is measured many times per second (44.1kHz in the case of CD).

Sampler - a hardware device or software application that uses samples as it's main method of generating it's audio output. Samplers often use a number of samples together to create realistic sounding reproductions of real sounds and musical instruments. For more details on this technique, see Wavetable Synthesis. Also called a digital sampler. A type of synthesizer which derives it's sounds from recording actual sounds (instruments or non musical sounds) and then storing them in computer memory, either floppy discs, hard drive, or recorded onto CD-ROM. They are used extensively for generating sound effects.

SAMPLING - digitizing a waveform by measuring its amplitude fluctuations at some precisely timed intervals. The accuracy of the measurements is a function of the bit resolution. Sampling is actually emulating the sound of an acoustical instrument by digitizing (converting to digital sound) the waveforms produced by the instrument. There are hardware samplers and software samplers, such as Tascam’s Gigastudio.

Sawtooth Wave: - So named as the shape of this wave (when pictured through an oscilloscope) resembles that of the jagged teeth of a saw. It differs from the Square wave described above in that it contains both even and odd harmonics (giving it a strident, somewhat aggressive quality).

SCSI (Pronounced SKUZZY) Port: The port on the back of the instrument to which SCSI devices are connected. SCSI: Abbreviation for Small Computer Systems Interface. An interfacing system for using hard drives, scanners, CD-ROM drives and similar peripherals with a computer. Each SCSI device has its own ID number and no two SCSI devices in the same chain must be set to the same number. The last SCSI device in the chain should be terminated, either via an internal terminator, where provided or via a plug-in terminator fitted to a free SCSI socket.

Secure Digital Music Initiative (SDMI): An initiative to bring together the worldwide music community in an open forum with technology companies to develop an open interoperable architecture and specification for digital music security.

Semiconductor: - 1) Material / Substance that is at the mid way point between being a conductor and an insulator, which is invaluable for creating transistors, which need to be capaple of switching from one state to another. Example of Semiconductive materials include Silicon (cheap and most widely used) Germanium, and Gallium Arsenide, which is a compound of gallium and arsenic. 2) Unless the material is what is known as an "intrinsic" semiconductor, where equal numbers of electrons and holes are present, a semiconductor material is doped ("extrinsic" semiconductor) with another substance. This is to help either with the conduction of as it will just be a neutral substance, which is neither a good conductor or insulator Can also describe a composite of materials, where semiconductive materials like the ones mentioned above are "doped" with a small amount other materials, such as arsenic, phosphorous or boron, known in this context as an "impurity". This increases certain types of conductivity within the material. There are two kinds of doping, doping with a substance such as phosphorous or arsenic. This helps with the conduction

Sequencer - a hardware device, software application or module used to arrange (ie. sequence) timed events into some order. In digital audio and music, sequencers are used to record and arrange MIDI and/or audio events into patterns and musical compositions. A computer program or dedicated device which records, processes, edits and plays back MIDI data. Can function like a musical "word processor" with cut, paste and copy functions. Can be synchronized directly to video or audio tape with time code. A device which steps through a series of events. A digital sequencer may record keyboard data, program changes, or realtime modulation data to be played back later much like a tape recorder or player piano. Digital sequencers use memory on the basis of events (key on, key off, etc.) while a tape recorder uses memory (tape) on the basis of time. MIDI software or less commonly, a hardware device that can record, edit and playback a sequence of MIDI data.

Serial Interface: A computer interface in which data is passed over a single line, one bit at a time. The MIDI interface is an example of a serial interface.

SESSION TAPE: The original tape made during a recording session.

Ship Date: The date on which the manufacturer physically mails or "ships" product for distribution.

SHORT CIRCUIT: A low resistance path that allows electrical current to flow. The term is usually used to describe a current path that exists through a fault condition.

Short Form Albums: Defined as configurations with at least three, but not more than five, cuts and a maximum running time of 30 minutes. Short-form albums are awarded at the same levels as full-length albums.

Sibelius: - Brand name for the most well known form of music notation software (software which transposes what is played into a musical score). Also a dead Scandinavian composer!

SIBILANCE: High frequency whistling or lisping sound that affects vocal recordings, due either to poor mic technique or excessive equalisation.

SIDE CHAIN: A part of the circuit that splits off a proportion of the main signal to be processed in some way. Compressor use the side-chain signal to derive their control signals.

SIGNAL CHAIN: Route taken by a signal from the input to a system to the output.

Signal Feed: - see Feed.

Signal Processing: The art of modifying an existing sound through the use of electronic circuitry.

Signal Processor: An electronic device which audio signals can be routed through to affect the sound of that signal. Examples: echo and reverb units, distortion devices, etc. Most electric guitarists run their instruments through 'pedals' which are small floor units that process signals at the press of a foot pedal.

Signal to Noise ratio (S/N): At it's most basic, this is the difference between the level of background noise (noise floor), and the level of signal, measured in dB's . The ratio between what goes in a device designed to alter or record sound, and what comes out the other end. If what you get out the other end is all distorted or hissy the piece of equipment has a low signal to noise ratio. A very expensive DAT machine for example, will have a high S/N ratio because what you get out will sound very close to what you put in. The same goes for a very expensive digital effects processor, if you want a sound to come out with reverb on it and instead it comes out with reverb and a bunch of hiss you would not be very happy.

SIGNAL: Electrical representation of input such as sound.

SIMD: Programming code, Single Instruction Multiple Data.

SINE WAVE - the most basic waveform, consisting of a single partial. Forms the basis of all complex, periodic sounds. Sine Wave A geometrical waveform having a curve defined by the function y= sin x. In theory there are no other partials present and it can therefore be considered as the basic component from which (by combination) all other waveforms are made. It is the basic building block of all sound. Sometimes used quite incorrectly to describe pure tones irrespective of waveform. See also See also Pulse Wave, Ramp Wave, Square Wave, Triangle Wave. The waveform of a pure tone with no harmonics.

SINGLE ENDED NOISE REDUCTION: A device for removing or attenuating the noise component of a signal, but that doesn't require previous coding, as in the case of Dolby or dbx.

Slave: - A device which is controlled by another device, which is referred to as the master.

Slider: An input-device to manipulate audio or MIDI data; a typical use is to increase or decrease volume. Programs will have this as an on-screen image, like a button control that one can move with a mouse.

SMPTE TIME CODE - a timing standard adopted by the Society of Motion Picture and Television Engineers for controlling different audio and video devices. Allows a sequencer and an external device such as a tape recorded to stay synchronized. (Society of Motion Pictures and Television Engineers) a.k.a. "Time Code.” Universally used and recognized standard for time and velocity. Digital machine code which contains hours, minutes, seconds and frames. Common formats in the US are 30 frames/second non-drop, and 29.97 frames/second drop-frame.

Software Sequencer: A sequencing software package designed to be loaded into a computer. Software sequencers usually have more features and have the advantage of showing you a lot more information at once because of it's computer screen. These have become incredibly popular due to the fact that computers with lots of processing power have become affordable to everyone. Products such as Arturia’s Moog can provide the user with a specific sound set, suitable for a particular composition. Bitheadz has a wide variety of synths such as Harry Sharpe Guitars that can be interfaced as a plug in. See Synthesizer.

Solid State: - Pertains to the solid qualities of a (usually crystalline) substance. In electronics, this usually means semiconductor materials. In the olden days, when transistors were still slugging it out with valves in amplifiers, radios etc, transistor devices were known as "Solid State" devices, due to their use of semiconductive "solid state" materials.

Song Pointer: MIDI information which allows equipment to remain in sync even if the master device has been fast forwarded. MIDI Song Pointer (sometimes called MIDI Song Position Pointer) is an internal register (in the sequencer or autolocator) which holds the number of MIDI beats since the start of the song.

SONG POSITION POINTER (SPP) - a system-common message that specifies where in a sequencer a device should begin to play.

Sound Blaster VOC: This is the format used by the Creative Voice SoundBlaster hardware used in IBM-compatible computers and is optimized for that hardware. It specifies sampling rate as a multiple of an internal clock and is not as flexible as the other general formats.

Sound Card - a hardware interface that is either built into a computer's motherboard or inserted into one of the computer's internal expansion slots. Sound cards allow the computer to play digital audio and/or musical instrument sounds. Many sound cards also provide a MIDI interface.

Sound Designer II: This is a popular format for professional sound editing on the Macintosh. It can specify arbitrary sampling rates and supports multiple channels and data sizes. More information about this format can be obtained from Digidesign, makers of ProTools.

Sound Module: Another term for MIDI sound generator, this refers to the synthesis component in a device such as a keyboard that produces the sound such as a violin or piano.

SOUND ON SOUND: Early recording technique to allow pseudo-multitracking. Also, Europe's No.1 hi-tech music recording magazine.

Sound Synthesis: - Bringing together different electronic sound elements (oscillators*, filters*, envelope generators* etc to make new, harmoncally interesting sounds. In the case of music to be played as notes.

Soundwave: - See Wave

Special 301: Special 301 is a provision of U.S. trade law requiring the identification of countries that deny adequate and effective copyright protection and market access to U.S. companies.

Spectral Balance: This is the balance across the entire frequency spectrum of the audio range.

Spectrum Analyser A device for displaying the relative amplitudes of a range of frequencies or partials in an audio signal.

Spectrum The range of frequencies or partials of an audio signal.

SPL: Sound Pressure Level measured in dBs.

SPP: Song Position Pointer (MIDI).

Square Wave A geometrical waveform typically generated by an oscillator. It is a special case of pulse wave, where the mark/space ratio is 1:2. It has only the odd numbered (1, 3, 5, 7, etc.) harmonic partials. The amplitude of each harmonic is the reciprocal of its number in the series (i.e. the 3rd. harmonic is a 3rd. the amplitude of the 1st.). It has a buzzy but mellow timbre very similar to that of a clarinet. See also Pulse Wave, Ramp Wave, Sine Wave, Triangle Wave.

Standard MIDI File: Usually seen as SMF files, this means that the MIDI file utilizes common parameters across different platforms and sequencers, such as the drums always being on MIDI channel 10. The significant advantage to this file format is assured compatibility regardless of what synth is used for playback.

STATUS BYTE - the first byte of a MIDI message that specifies what type of message it is.

STEP TIME - entering notes one by one, as opposed to real time recording in a sequencer.

Step Up / Step Down Transformer: - see Transformer.

STEREO: two-channel system feeding left and right loudspeakers.

STICKY SHED SYNDROME: A problem affecting some brands of analogue tape after a long time in storage. A breakdown of the binder causes the oxide to shed, and the tape tends to adhere to the tape heads and guides when played. A short term cure can be affected by baking the affected tape for several hours at 50 degrees C.

Streaming Audio: Refers to the process of making a broadcast of audio available on the Internet.

Street Date: The date on which the product actually arrives on the "street" in retail stores or ancillary markets for sale and distribution; the date which product is commercially available for public sale.

STRIPE: To record time code onto one track of a multitrack tape machine.

SUB BASS: Frequencies below the range of typical monitor loudspeakers. Some define sub-bass as frequencies that can be felt rather than heard. Bass frequencies which are below the point where sound is directional (@ 150Hertz) and above the point where it can no longer be heard (@20 Hertz). below this, it is known as "infra bass". It is the fact that sound is not directional below 150 Hz (you dont need a stereo pair to recreate its position in space) which enable the design of loudspeaker systems with solitary sub bass units which may be tucked away behind sofa's etc!

SUBCODE: Hidden data within the CD and DAT format that includes such information as the absolute time location, number of tracks, total running time and so on.

Subtractive Synthesis:- The opposite of Additive Synthesis (see above) The synthesis of a new sound by the refinement through filters etc of a harmonically complex waveform. The process of constructing a sound by starting with a complex sound and then removing harmonics with a filter. A low pass filter is most commonly used. The cutoff frequency of the filter is usually dynamically varied, which changes the harmonics that are removed. Using the low pass filter on the Emulator III to alter the sound is a form of subtractive synthesis. The process of creating a new sound by filtering and shaping a raw, harmonically complex waveform.

Sun Audio (AU) and NeXT: Internally, these are the same formats. The format specifies arbitrary sampling rates and multi-channel sounds. It supports a number of sound encodings, including µ-law, a-law, various linear formats of varying sample sizes, floating point samples, native DSP samples and G.72x ADPCM compression. These compressed formats are not very popular due to the extremely slow decompression rates. The U.S. telephone system uses µ-law encoding for digitization, whereas the European telephone systems use a-law encoding.

Super Audio CD (SACD): A high-density disc format that uses a proprietary audio system of very high quality developed by Philips and Sony. Like the DVD, SACD will also have extra capacity that will be used to achieve a high-quality, multi-channel surround sound that is significantly better than current CDs, and may also be used to include features such as text, graphics, video and interactivity. SACD audio discs will require new players, but most, if not all, new SACD players will also play consumers’ existing CD collections.

Supercardioid: - see Polar Pattern (cardioid).

Supermode: An Emulator III MIDI function designed to enhance the Sequencer/MIDI interface. It maps data occurring on a specific MIDI channel to a specific preset within the bank. Similar to standard MIDI Omni Off/Mono mode, but more flexible. Each channel can contain polyphonic note data.

Supply Reel / Take up reel : - On a cassette / video / reel to reel etc tape, the reel on the left is known as the Supply Reel, and the reel on the right is known as the Take Up Reel.

SURGE: Sudden increase in mains voltage.

Sustain - the period of an envelope during which a sound's attribute (such as volume) holds at a constant level. The sustain period starts at the end of the decay period and holds until the release period is started (usually by a keyboard note release). Unlike the other periods of an envelope, the sustain period does not have a slope because it must be capable of holding indefinitely (as long as a keyboard note is pressed). Part of the ADSR envelope which determines the level to which the sound will settle if a key is held down. Once the key is released, the sound decays at a rate set by the Release parameter. Also refers to a guitar's ability to hold notes which decay very slowly.

SUSTAIN PEDAL - a pedal on a MIDI controller (or acoustic piano) that keeps all notes sounding even a key is released.

Sweet Spot": - The optimum position for a listener within the sound field created by a pair of stereo speakers, or the optimum position for a microphone relative to it's pickup pattern and the sound field created by whatever is being recorded. The optimum position for a microphone, or for a listener relative to monitor loudspeakers.

SWITCHING POWER SUPPLY: A type of power supply that uses a high frequency oscillator prior to the transformer so that a smaller, lighter transformer may be used. These power supplies are commonly used in computers and some synthesizer modules.

SYNC: A system for making two or more pieces of equipment run in synchronism with each other.

Synclavier: - Highly complex (in the old days anyway!) digital synthesiser/ music workstation developed by Sydney Alonso (hardware) and Cameron Jones (software) at Dartmouth College, New Hampshire, United States. The first prototype was released in 1975. Like the Fairlight mentioned above, the Synclavier made a great impact on the increasingly digitally based music of the 1980's. The current homepage of the Synclavier is here .

Syncopate - to shift the regular accent of a tone or beat by beginning on an unaccented beat and continuing through the next accented beat.

Synthesiser (1) An electronic device for making sounds, in which the shape and method of construction have little effect on the nature of the sound produced. This wide definition includes: Electronic organs, samplers, drum machines even radio sets etc. as well as those devices which are more immediately recognised as synthesisers. Some devices, such as the Thérémin do owe their sound, in part, to their construction, and may be considered somewhat "grey" in respect of this definition. (2) A specific case of (1) above, equipped with oscillators, filters, amplifiers as well as modulation sources. Either with a predetermined or more or less programmable audio and control signal path, which can be used as a musical instrument or for sound effects. The oscillators may include the ability to replay digital recordings of sounds, and the whole or part of the system may be implemented using digital or analogue technologies.

SYSEX: System Exclusive Messages or Sysex messages do exactly what is implied - they send commands specific to a particular device in a MIDI setup where global control of all settings is not desired. They are particularly useful if your MIDI modules or keyboards are in a chain and isolated commands are necessary.

System 7 and 'snd ': System 7 sound files are simply type 1 'snd ' resources. System 7 provides the familiar icon for them and permits playback in the Finder by double-clicking on them. An 'snd ' is a type of resource which consists of a series of commands for use by the Sound Manager. Any number of the three types can be combined with various effects to produce complex sound files. Simple Beep is an example of a non-digitized 'snd '. For more information on 'snd ' filesconsult Inside Macintosh VI or Inside Macintosh: Sound.

SYSTEM COMMON MESSAGES - MIDI messages used for various functions including tuning an instrument and song selection. MIDI data which is not specific to any one channel. System data includes system exclusive messages (an instrument’s internal data, sometimes called bulk dump data), system realtime messages (sequencer start, stop, and continue commands as well as MIDI clock and other timing information) and system common messages (song select, tuning requests, system reset, etc.).

SYSTEM REAL TIME MESSAGES - commands used to synchronize one MIDI device with another.

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