Synth Glossary 1
Access : Find. Access an item of
information find in item of information.
ADC : Analog to Digital Converter. A device which takes-in analog
(electrical) information and converts it to numeric (digital) information.
In music computers, the device which takes input from a keyboard (or other
analog sound source) and converts it into information the computer can
Additive synthesis : The process of building up a sound by adding
harmonic waveshapes to a fundamental.
ADSR : An acronym for Attack, Decay, Sustain and
Release, referring to the dynamic characteristics common to all sounds. In
an analog synthesizer the ADSR control provides control over these parameters
and considerable sound modifying possibilities.
Alphanumeric : Alphanumeric keyboard: a keyboard with letters and
numbers as in a typewriter keyboard. Alphanumeric information: information
consisting of letters and numbers.
Algorithm : The various steps necessary to find the solution to a
problem. A logical progression of procedures that will lead to the end result.
ALU : Arithmetic and Logic Unit. Part of a central processor that
actually executes the operations requested by an input command.
Analog : An electronic signal whose waveform
resembles that of the original signal. Analog synthesizers are those that
produce sound by electronic means. Conversely, computers produce sound digitally,
which is the numeric representation of sound. Computer music is not, and
should not be called, electronic music.
ASCII : The ASCII code is the 'American Standard Code for Information
Interchange.' This code has been developed to allow computers to communicate
in a common language. Communication is often by telephone, computers connected
via modems. The rate at which information passes is relatively slow.
Assembler language : A language that is close to the original binary
language of computers. The language includes symbolic machine language statements
which relate directly to the instruction and data formats of the computer.
Used by advanced programmers.
Assignable : Capable of altered function. An 'assignable' control
may have several functions under the control of software.
Audio-cassette : A connection allowing ordinary cassette interface
recorders to be connected to computers for the purpose of storing programs
on cassette tapes.
Backup : Copy. For safety reasons every computer program should be
backed up so that if a program is lost during operation, or if a storage
medium should become damaged, a safety copy, or backup is available. 'To
backup' = to copy.
Bandwidth : Frequency range. A hi-fi system can typically deliver
sound between 20Hz and 20KHz (20 and 20,000 cycles). Many computer music
systems can only produce sound in relatively narrow bandwidths - up to 10K
for instance - but these can make acceptable sounds. The human auditory circuits
classify everything above 5K as very high treble. When high- end is missing
clarity and sparkle is the most noticeable lack.
BASIC : 'Beginner's All-purpose Symbolic Instruction Code.' A high-level
computer language developed in the fifties at Dartmouth College. BASIC is
the language that most home computers work on. It is an ideal language for
amateur programmers, but is too slow in operation for professional use.
Boot : To 'boot up' a disk. Jargon for inserting a disk, issuing the
instruction to the computer to identify and initialize the disk and place
it 'on line' for information storage and retrieval. A 'boot track' on a disk
is a built-in program which carries out the above procedure.
Bubble memory : A non-volatile memory device which stores numeric
information safely even when power is withdrawn. Information is stored as
magnetic 'bubbles' on a sliver of synthetic garnet. Microscopic in size,
the bubbles follow a path through a circuit and when stopped provide a pattern
of 1 and 0 information which is a permanent memory. Expensive but excellent.
Bug : An error in a computer program. Software is such a complex science
that many programs are sold to the public before all the errors (bugs) have
been discovered. During use some of the errors show up and the manufacturers
usually develop revised programs which are 'de-bugged' and supply them it
nominal cost to existing users.
Byte : A byte is a 'phrase' made up of the smallest items in computer
language - the 'bits.' Often 8-bits make a byte and that phrase can represent
one character or two numerals.
C language : A high level programming language used by factory software
writers. Soon to be used as: the main language in a major dedicated
Chip : Slang for microprocessor. Actually a very thin slice of
semi-conductor material of which microscopic electronic components are
photo-etched to make circuits. It becomes an 'integrated circuit' when connection
tags and a plastic case are added. Complete microcomputers on chips are now
possible, usually measuring only a quarter or an inch square.
Click-track : Once tempo is set for recording, a click track is placed
on to one track of a multi-track tape machine. This track provides
synchronization for later parts.
Come up : Jargon for powering up a computer.
Control voltage : The electrical signal which, in an analog synthesizer,
specifies which frequency is played by the oscillators.
CPU : Central Processing Unit. The primary unit of a microcomputer
that includes the circuits controlling the interpretation and execution of
CRT : Cathode Ray Tube. A television-type screen.
Cursor : The 'blinking dot' on a computer screen that shows the user
where he is working.
DAC : Digital to Analog Converter. A device which converts digital
information in computers into analog (electrical or physical) signals which
an audio system can amplify.
Data : Information that defines a specific task. A computer program
may be written to solve a particular type of problem but specific 'data'
must be provided before an individual calculation can be computed.
Debug : To find the fault in a computer program. Only necessary when
new programs are generated, not when programming musically. A debugger is
a program within a program that automatically searches for illegal program
entries and reveals them to the user.
Dedicated : As in dedicated music computer. A computer designed
specifically for one task.
Dot-matrix : Dot-matrix printer. A computer printer that makes up
letters and graphics by firing dots of ink at the paper. More versatile than
typewriter-quality printers and good for printing music.
Dump : 1) 'Off load': usually applied when a program is 'dumped,'
or off-loaded to storage medium such as disk or cassette. 2) A power dump,
when all power is removed from the computer.
Digital : The binary code: the 01011001-style
numeric language on which all computers are based. Refers to systems that
are computer based. Digital sound -sound that is stored as numbers.
Disk drive : The mechanical system which spins a floppy disk at high
speed and applies a magnetic head immediately above the surface of the disk
for information access. In some computers the disk drives are built into
the chassis. in others they are supplied as separate, free- standing-units
connected by ribbon cable. A typical disk drive provides 150-300K of storage.
DMA : Direct Memory Access. A form of data transfer employed when
it is vital that information should be stored and retrieved quickly from
disk. In this system, data is transferred automatically after the CPU has
initiated the transfer without requiring super vision, freeing the CPU for
Dolby : A Method of noise reduction for audio signals created by
Eight(8)-bit : See Sixteen(16)-bit.
Envelope : The 'shape' of a sound, when displayed graphically; typically
of an 'ADSR' pattern. A graph indicating
the development of a sound.
Event-recorder : Used by some music-computer companies to describe
a sequencer-type program. Note- rests, and ties are all events in music and
when a sequencer is described as an event recorder it usually means that
the system will store information about which notes were played but will
not store information about how they were played: key velocity, etc.
Fourier synthesis : The Fourier mathematical formula argues that any
complex waveform may be resolved into a fundamental plus a set number of
harmonics. A formula widely used to allow computers to compute the gaps between
information supplied about harmonic envelopes.
Floppy disks : A storage medium for computer information. Looks similar
to flimsy disks used for promotions by the record industry but is protected
in a paper sleeve. Disk spins at high speed inside paper sleeve when inserted
in disk drive and the information, stored in 'tracks' on the disk, is read
by a magnetic head that floats above the surface of the disk. An efficient,
cost-effective method of information storage and retrieval.
Free-standing : Not part of a greater item of equipment.
Fundamental : In waveshaping, the root harmonic on which other harmonics
Graphics display : A CRT screen built specifically for displaying
graphics. Many ordinary computer screens do not have sufficiently high-resolution
for high-quality graphics displays. Fairlight had to have a screen custom-built
to allow its graphic displays of sound waves to be shown.
Go down : Letting the system 'go down.' Turning the thing off. Sole
meaning in computer parlance.
Hard copy : Printout on good old-fashioned paper.
Hard disk : An advanced, large capacity, storage system for
microcomputers. Only just available (for a few dedicated music-computers),
hard disks operate like floppy disks, but store four or more times the amount
Headroom : A term that has spilled over into music- computing from
the recording industry. Headroom was the gap between the peak working level
on tape and the point at which the sound might actually distort. In computer
parlance 'having the headroom' means having sufficient spare computing power.
Hexadecimal : A code of counting in which
16 is used as the base. Used in low-level computer languages which are slow
to write but very flexible.
High-level language : The language in which the end-user writes programs.
These languages usually allow programming in English-type statements such
as 'goto' or 'next' and are developed to allow users to consider the problems
in hand rather than worrying about correct addressing of the microprocessor.
Machine language is the final target language and is controlled by a structure
of high-level language controlling intermediate languages. In effect this
is a layered operation: the user says what he or she wants in plain terms,
the high-level language translates that into compiler, the compiler issues
instructions to assembler which generates machine code.
I/O device : See input/output device.
Illegal commands : An instruction the computer is unable to recognize.
Initialize : The start-up procedure for computer systems using peripheral
units such as disk drives or printers. The initialization program sets up
the starting condition.
Input/output device : Any device which allows the
computer to communicate with the outside world, and vice versa. An alphanumeric
keyboard is an I/O device, so is a CRT screen (when a light pen is added
for input), a musical keyboard is often an input device and sometimes also
an output device.
Instruction : A coded program step that tells the computer what to
Integrated circuit : IC. A group of circuits formed at the same time
which are interconnected and capable of performing a complete function. The
IC is usually mounted in a plastic package and connecting pins protrude from
two sides rather like legs.
Interface : Matching connection. For a computer to interface with
a synthesizer a suitable interface (matching connection) must be made.
Keys-down : Keys-down information. Information from musical-keyboard
keys: how hard the key was played, how fast it was pushed down, how long
was it held down etc. This is the 'keys-down' information that a high-quality
music computer system should be able to read from the musical keyboard. This
information is stored and reproduced to control replay of the sounds. It
may be edited by the user.
Keystroke : One 'press' of a key on an alphanumeric keyboard.
Diode. A display system often found in inexpensive electronic items.
Made by sandwiching liquid-crystal and electrodes between two sheets of glass.
Current causes the liquid to change its light-trapping proper ties so forming
letters or numbers.
Light pen : A clever, high-speed pen-shaped device which, when held
against a CRT, can issue instructions for program or graphics purposes. The
pen usually doesn't admit light, a photo-sensitive cell in the pen reacts
to light from the screen. Placing the pen over the relevant command shown
on a screen will cause that command to be carried out. Simple versions can
be seen reading bar codes at supermarket check-outs. Casio apply a similar
system for entering music from bar codes into their small microprocessor
Load : To place the program into the computer's 'live' RAM memory
usually loading is done from a storage device such as cassette or disk.
Lockout : A situation during computer operation when the arithmetic
and logic units both try to access the CPU at the same time - usually the
result of illegal commands in an unfriendly program. The computer just ceases
to work. Only solution is to turn the damn thing off and start again - losing
the work in hand.
Low-pass filter : Also high-pass filter. Filters which allow certain
frequencies to pass, but 'cutoff' unwanted frequencies. Used in music computers
to reduce unnecessary frequency analysis.
LSI : Large Scale Integration. The state of the art before the VLSI.
Refers to a component density of more than 100 per chip.
Machine language : Binary language, the language of 0 and 1 that all
computers finally work on.
Mainframe : Mainframe refers to the basic or main part of the computer,
the CPU. In everyday use mainframe computer refers to the large, ultra-powerful
computers operated by governments and multi-national corporations in which
the 'main' element in the name distinguishes the unit from smaller satellite
terminals which may be able to interface with it.
Menu-driven : A software-design style in which the program offers
the user a 'menu' of choices whenever a decision has to be made. Rapidly
gaining in popularity, menu-driven programs are easy to use and reduce the
demands on the end user to a minimum.
Microcomputer : A small computer system, usually based on one or two
microprocessors, which sells for a few hundred dollars or pounds. Typical
units use domestic television screens for display, interface with domestic
cassette recorders for ROM and have no hard printout facility built-in.
Microprocessor : The CPU (Central processing unit) of a computer.
Built in layers on a microscopic chip of silicon.
Modem : A MODulation/DEModulation device that allows computers to
connect to telephone lines. Using a Modem to hook into the telephone lines
allows computers in remote locations to interchange information using the
Monophonic : One note. A monophonic system can play only one note
at one time.
Multiplexer : A device that takes input from several sources and delivers
them in one high-speed stream of information.
Music Concrète : The pioneering style of electronic music popular
in the 1950s and 1960s which, to some extent, has got synthesized and computer
music a bad name.
Nanosecond : Particle of time equal to one billionth of a second (UK
equivalent is one thousand, millionth of a second).
Nest(ed) : A program within a program. Nested menus are menus that
offer decision choices subsequent to original menu choice.
Off-load : To store program on magnetic storage device such as cassette
On-line : 1) Available. Being 'on line' means that a piece of information,
a program or a computer peripheral is ready to be used. 2) Communicating.
Operating system : The basic programs that cause the computer to operate
before specific function programs are loaded.
Overlay : A system of software design which allows long programs to
be written and stored on disk ready to be called when required. During operation
the part of the program currently in RAM will automatically call the next
part of the program out of ROM which will load into RAM 'overlaying' and
erasing the earlier program.
Parameter : A variable; a measurement.
Peripheral : A computer peripheral is a unit that is separate to the
main computer - a printer, a disk drive, a musical keyboard.
Port : A socket, usually built into the computer, which allows information
to pass in and out.
Polyphony : The ability to sound more than one note at the same time.
8-voice polyphony the ability to sound eight separate notes at once.
Program : Never programme. A list of instructions telling a
computer precisely what to do. In musical applications a program might be
the order of musical events as entered by a musician into a computer-based
Quantization : 1) Quantization noise/quantization error. The noise
which occurs in digital sound reproduction when numerical expressions of
sound are rounded off to their nearest numerical equivalent. Every measurement
may be expressed in infinite terms, but when measurement is rounded off for
the purposes of finite computation, small errors occur and, in sound
reproduction, cause background noise. In musical applications, the more power
the computer has the greater degree of measurement accuracy is possible,
thus the lower the level of background noise. A problem that has been largely
overcome. 2) Rounding a note to the nearest time segment
RAM : Random Access Memory. The operating part of a computer's memory.
The user can access any part of this memory at random and order it to perform
computations. RAM is the main measurement of computer power. Home computers
currently offer between 1K and 128K RAM, although some home/business machines
are capable of offering up to 900K RAM. Music computers rise to 256K RAM
Real-time : Live: happening now. When you play a piano you are playing
in real-time. When you program a computer to play a piano part you are
programming in real-time but, as a whole, the piece of music has been created
out of. real-time. When the computer plays the program it is playing
Reset-switch : A switch found on most microcomputers which completely
wipes all RAM and resets the computer to an 'empty' mode.
ROM : Read Only Memory. A non-volatile (permanent) memory system which
can only be 'read from' in a certain sequence. Information stored in the
memory cannot be accessed at random, but must be loaded into RAM where it
may be accessed. ROM is used for the permanent and semi-permanent storage
of information and typical ROM mediums include ROM chips (on which a program
is written by the factory), floppy disks, hard disks and cassette tapes.
Sampling Rate : In musical applications, the rate at which a computer
measures sound. External sound is fed to a music computer, e.g. the Fairlight,
via an analog to digital converter. Within this device the sound wave is
measured a fixed number of times per second. The frequency at which the sound
is measured is called the sampling rate and the higher the rate, the more
accurate the sample. For professional fidelity, the sampling rates chosen
by the recording industry are between 40,000 and 50,000 times per second.
Semiconductor : The item at the heart of the computer. A material
with an electrical conductivity some where between a good conductor (metal)
and a poor conductor (insulating material.) Its conductivity increases as
its temperature rises. As a device, a semiconductor is made from silicon,
germanium or similar material and its basic function in computer applications
is to represent 'on' or 'off': expressed another way, 1 or 0.
Sequencer : A microprocessor device for remembering control information.
In the past sequencers have been used to control analog synthesizers, but
now most computer-based instruments have built-in sequencers which act like
tape recorders. They record all of the information from a series of notes
and will replay those notes on demand. Many allow 'overdubbing.'
Silicon : One of the earth's most common materials (covering our beaches),
silicon has proved to be one of the most important materials ever applied
in technology. A perfect semiconductor and the material from which most
microprocessors are constructed.
Sixteen(16)-bit : The 'bit' size in computer measurement
parlance refers to the number of bits that can move through a computer at
once - the width of information that can be handled. The wider the path,
the more information can pass through at one time. Many TV games operate
quite successfully on a 4-bit system, standard home computers are currently
8-bit and the new generation of microcomputers use 16-bit - e.g. the IBM
personal and the Radio Shack Model 16. Some computer designs use 16-bit systems
in one part of the information path and 8-bit in others. Microprocessors
themselves are designed as 8-bit or 16-bit units. At the beginning of 1981
several US corporations announced the development of 32-bit microprocessors
and although there are, as yet, no domestic systems or software programs
available using this technology, the 32-bit system will produce a microcomputer
with power equivalent to some of the mainframe computers. Most music computers
are currently using 8-bit technology. [As of now the 8 and 16 bit machines
have been superceded]
Soft : Soft-instrument. An increasing number of musical instruments
are now soft. The phrase means that the instrument is computer-based and
performs according to software instructions. Modification in the software
results in a change in the instruments performance. Fully soft instruments
are not yet with us; all current music computers require some special hardware
to carry out musical functions. This special hardware limits the adaptability
of the instruments. It is likely that the first really soft instruments will
appear within five years.
Software : A collective name for all computer programs. Instructions
for the computer are always soft, the mechanical and electrical elements
of the computer are hardware.
Software gap : A gap that is opening between the capabilities of hardware
and the people who write programs to control it. Computer development is
following an exponential curve and
artificial intelligence capability is increasing
by compound leaps each year. Programmers are struggling to write programs
that make efficient use of power now available.
Solid-state : Any electrical circuit built without electro mechanical
parts such as tubes (valves). Transistor circuitry.
Speech-analyzer : A system that can recognize spoken words and transform
them to computer commands. Under heavy research, but proving difficult to
perfect. Ask a computer to differentiate between 'I saw' and 'eyesore.' Speech
recognition is one of the major goals of the Japanese drive to develop the
'5th Generation' of computers, but successful recognition systems capable
of fully understanding speech might not be available for ten years.
String : A string of numbers or letters grouped together: usually
in a computer program.
Stripe card reader : A device that decodes information contained in
a strip of magnetic tape usually embedded in a plastic card. As used in Yamaha
digital instruments and others.
Subroutine : A secondary part of a computer program which is called
up during program operation to carry out a specific task.
Tracks : A term sometimes used by companies producing soft instruments
to describe a multiple sequencer. In suggesting that a digital sequencer
has 16-tracks, the manufacturers are comparing the system to 16-track analog
tape recorders to help users visualize the facility. Often the facility isn't
identical as tracks placed on top of tracks can't he accessed separately
for subsequent editing or mixing.
Trigger : To trigger: to set-off, to start. A trigger into an analog
input causes the relevant note to sound.
User-friendly : Usually applied to program design. A user friendly
program or system is one that makes operation easy for unskilled operators.
User language : The language in which the user communicates with the
computer - often bad!
Utilities : Basic programs in a computer system such as DOS (disk
operating systems) and languages.
VDU : Visual Display Unit. VDUs are intended for business use and
display 80 characters horizontally against the more normal 40 characters
found on micro-computer screens.
Wave : As in sound wave. The shape of the graph (wave-like) that
represents the frequency of a sound.
Waveform memory : A computer memory device, either RAM or ROM, which
holds all of the information pertaining to a waveform.
Waveform table : A method of arranging information about a waveform
that sets it out as a table in computer memory allowing the user rapid access
to any part of the information.
Write : To copy. To write to disk means to copy the information on
to a disk for storage purposes.