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SYNSOUNDS
by Tim Closs
from Your Computer February 1985

Tim Closs provides a useful facility on a machine not noted for
its sound potential - the Spectrum.


THIS PROGRAM converts the 48K Sinclair ZX
Spectrum into a versatile electronic keyboard.
Up to 100 different sound effects can be
synthesised by the user, any 10 of which can
be accessed instantly while playing a piece of
music. In addition, seven riffs can be stored in
the memory and incorporated into the
performance at the touch of a key.


Facilities on a main menu

	All the facilities offered are obtainable from
a main menu displayed at the start of the
program:

 Play.
 Synthesise sound effects.
 Assign sound effects.
 Compose riffs.

	Play: When this option is selected the
screen is cleared and the computer keyboard is
arranged as in Figure 1. The labelled keys in
the middle two rows are set out like a piano
and can be played in a similar manner.
However, three octaves are available since
pressing Octave Down will lower all notes by
one octave and Octave Up will raise them.
Hours of fun can be had from this basic
electronic keyboard, even if your musical
talent is strictly limited. But there's much
more to come.

	Synthesise sound effects: The essence of a
synthesiser is to alter the kind of sound
produced without altering the musical pitch
of the notes themselves. On the Spectrum this
can be achieved by causing a rapid change of
frequency as the note is played; the particular
"frequency waveform" governs the character
of the sound emitted. In this program the user
is able to invent as many as 100 unique
frequency waveforms as follows.

	On choosing menu option 2 you are first
required to enter the number of the sound
effect you are about to synthesise. This should
be within the range 0-99. Having done this
two axes will appear on the screen - see
Figure 2. The horizontal time axis covers the
duration of the note, and is divided into 16
sectors, while the vertical axis represents
frequency.


Beep returns you to menu

	To draw out your frequency waveform keys
6 and 7 are used to move a bar up and down
each sector and key 0 enters the desired level
when it is reached. After levels in all 16
sectors have been defined in this way, a short
beep returns you to the main menu.

	Some examples of waveforms are depicted
in Figure 3, but you will obviously want to
experiment with your own ideas.

	Assign sound effects: From your bank of
frequency waveforms produced in menu
option 2 any 10 can be chosen for instant
recall at the touch of a button. Simply type in
a number from 1-10, followed by the number
of the waveforms. When you now play the
piano keyboard, each note will take on the
"flavour" of the sound effect chosen. Pressing
another of the keys 1-10 will change to a new
sound effect without interrupting the flow of
music.


Play sequence of notes

	Compose riffs: It is often necessary to play a
short riff - sequence of notes - which is
repeated many times and may be complicated
or fast. Synsounds allows up to seven riffs to
be stored simultaneously and then replayed by
pressing a single key. It is thus possible to give
a creditable musical performance with a
minimum of stamina and skill. On the
computer keyboard in Figure 1 the keys
labelled (i) to (vii) in the bottom row refer to
these pre-programmed riffs.

	After entering the number of the riffs you
wish to compose (0-6), the Spectrum will draw
up a chart of all the notes playable - three
octaves. Each note has a number 0-36 - 0 for
the lowest C and 36 for the highest, and it is
this number that you must enter to place the
desired note in the memory. Up to 16 notes
can be entered in a single program, but if less
than this number are required then typing 255
will complete the riff and return you to the
main menu.

	Longer notes can be entered by repeating
the note several times.

	Note that the riff will be played in the
current waveform, so the "flavour" of the riff
can be altered by pressing any of the keys 1-10.

	Sound produced only by the Spectrum's
internal speaker will rarely be of sufficient
volume, so amplification can be achieved by
connecting the MIC socket on the tape recorder
to the MIC socket on the Spectrum and push
down the record button on the recorder.


Entering Synsounds

To enter Synsounds, I advise the following method:
1.	Enter the BASIC program from listing 1.
	Save it by typing: SAVE "SYNSOUNDS" LINE 5.
2.	NEW the program.
3.	Type in the BASIC program from listing 2.
	Type in RUN.
4.	Enter the code from listing 3 - work from
	left to right and from up to down.
5.	Save the code directly after the first
	BASIC program by typing:
	SAVE "CODE 1" CODE 31965,204:
	SAVE "CODE 2+3" CODE 32768,1922.
6.	NEW the program.
7.	Load the finished program by rewinding
	the tape and typing: LOAD "SYNSOUNDS".
