TRANSCRIPT OF SID CLASS NOV. 8:

Welcome to the SID class!  Each of you
signed up for this class with one thing
in common -- you like SID music. That
is actually the only pre-requisite
needed.

We'll be learning how to create SIDS --
from the very beginning all the way to
the complexities of SID Stereo files.
If you already know how to build SIDS,
then please bear with us these first
couple of classes.  If you're a rank
beginner to SID music, feel welcome
here.  We were all new once, and each
question that ::you:: ask has been
asked by everyone at some point.  Don't
be shy -- asking is essentially the
real way to learn.

In tonight's class we will cover
several areas.  I assume each of you
has the Sid Editor now.  This is the
program that we create the music with.
If you've taken a look at the Editor,
you'll understand that it's a pretty
complex program.

The Editor is broken into 3 separate
screens:  the editing screen, the
command screen, and the display 
screen.  The Editing Screen is where
is notes of the music are entered,
the key signature and the time
signature are set.  You can enter
music by either joystick control or
keyboard control or a mixture of
both.

The command screen is where the
parameters for the voice are set.
The C64/128 has one sid chip, which
has 3 voices.  Since it is a 
synthesized chip, each voice can be
set separately to achieve a full
sound.

The display screen will show the
parameter settings for each voice,
illustrating the changes in the voice
settings as the song plays.

The Enhanced Sid Editor contains some
commands that aren't included in the
first Editor.  The public domain sid
players cannot play SIDS that contain
these "enhanced" commands.

The "enhanced" commands are:
   PVD      RDN     SRC      HLD
   PVR      DST     SCA
   P&V      MAX     RUP
   RTP      UTV     LFO

There are three essential
characteristics of sound:  vibration,
waveform and volume.  The rate of
vibration is called "frequency" and
determines the pitch of a sound.  The
waveform determines the tone or timbre
of a sound.  Square, triangle and
sawtooth are common basic waveforms.
The volume of a sound changes levels
over a short period, and is called an
"envelope".  The envelope consists of
four parts:  attack, decay, sustain and
release.  During the first 3 parts, the
volume rises to a peak, then falls to
a sustain level.  As the note is
released, the volume fades to silence.

The easiest way to study the envelopes
of a SID is to load the .mus file into
the Sid Editor and take a look at how
the SID was made.  Note how the artist
changes the voice envelopes to put
emphasis on certain measures.  Become
familiar with what different "feelings"
each envelope setting can lend.
Experiment is the key here.  You can
take a SID artist's envelope settings
and use them exactly the same in your
own sids, and chances are the SID will
fail.  This is due to many factors,
including tempo and note duration.
Keep in mind that voice envelope
settings work best if they are chosen
for ::that:: particular song.  With
care, you can put emotion into a song
merely through your choice of
envelopes.

One more characteristic of envelopes
is the release point .. the PNT
command.  Note durations are dealt
with in terms of time units called
"jiffies".  One jiffy lasts for about
1/60 second.  The faster the tempo,
the shorter the jiffy duration.  The
PNT command specifies how many jiffies
from the end of a note the release
should begin.  The higher values of
PNT will give you a more pronounced
staccato effect, the lower values
give a more legato affect.  A PNT
setting of 0 will sound as if a tie
has been placed on each note, smoothing
one note into another.  If you set the
PNT too high, small duration notes
are apt to be lost.  Therefore, PNT
will differ from song to song ...
even ::within:: a song.

Again, remember that you are dealing
with a synthesizer chip.  You can
change envelope settings at any point
during a song, even every few notes if
you want to.

Sheet music will show you the key
signature of that song.  Beside the
clef symbol (the large symbol on the
left side of the top staff of music),
you might see a number of sharps (#)
or flats (b).  You don't have to know
what the key actually is, just count
the number of symbols there.  On the
editing screen, use the Commodore key
and the + key for sharps (#), and the
Commodore key and the - key for flats
(b).  Hold down the Commodore key and
press the appropriate key the same
number of times it appears on the sheet
music.  This will set the Sid Editor
to the appropriate key. It's the
::first:: thing you should do when
creating a SID.  If no sharp or flat
symbols are written beside the Clef,
then the music is in the key of C --
which is the default key of the Sid
Editor.

A song is a sequence of notes of
different pitches and durations.  These
notes are dealt with in groups called
measures; each measure consists of the
same number of beats -- four is most
common.  A measure is formed on the
sheet music by a line called a "bar".
Measures are mainly for organizing and
reference.  A good idea for beginners
is to number your measures in pencil
on the sheet music.  This will help you
keep track as you enter the notes, and
will aid you in referring back to
certain measures.

Usually sheet music contains a repeated
phrase.  Sometimes the repeat phrase
will contain a second ending that is
different from the first.  And 
sometimes the phrase will be repeated
with ::no:: changes.  The Sid Editor
has two commands which support repeats
and will make your life a lot easier!

The simplest form of repetition is
when a group of measures repeat
immediately after they are played.
You can spot this on sheet music by
special symbols.  It saves having to
write the notes twice.  The symbol
which marks the beginning of this 
simple repeat consists of two vertical
lines followed by two dots at the
beginning of a measure.  The end of
the repeat is marked by the same
double lines, but the dot comes 
:before: the lines.

When the music plays and the first
symbol is reached, playing continues
as usual.  When the second symbol is
reached, playing jumps immediately
:back: to the measure which contained
the beginning repeat symbol.  Then when
playing again reaches the second
symbol, it is ignored and playing
continues with the next measure.

This is where the HED and TAL
commands enter.  HED stands for
"repeat head", and the number you
place for this command tells how
many times the phrase will be 
repeated.  In a standard repeat, the
phrase is repeated once, meaning that
the sequence is played a total of
two times.  Thus, you'd normally enter
the number 2  for the HED command.  The
HED command is placed at the :start:
of the measure that contained the
beginning repeat command.

The TAL command (repeat tail) has no
data value, but the Editor requires
that you enter a number.  You can
type any number from 0 to 9.  When the
Editor or Player encounters the TAL
command it knows the repeat phrase
ends at that point.  The TAL command
is placed at the ::end:: of the
measure that contains the ending
repeat command.

Think of it as a loop -- the music
plays a phrase, loops back to the
beginning and repeats the phrase, then
moves on.  Instead of re-entering all
those notes to repeat the phrase,
the HED and TAL command do it for you.

Another useful application of the HED
command is to make a note repeat
numerous times, for instance in a
bass line.  The HED and TAL command
don't have to be used solely with 
repeat phrases.  To make a note repeat
16 times, for instance, just place the
HED before the note, with the value of
16, and place the TAL immediately after
the note.

Remember, each time the HED command is
used, it also must have a TAL somewhere
within the music.  You can use the
HED command as often as you like, but
just be sure the TAL is also used.
Each voice can have it's own repeat,
and repeat independently of the other
voices.

Outline for class of Nov. 15:
    1.  Defining phrases (DEF/END/CAL)
    2.  Envelope tips
    3.  Tempo restrictions