The Sid Filter - Commodore 128D User Manual

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piano envelope in line 40 and the redefined
piano envelope in line 70. Line 40 actually
sounds more like a piano than line 70.
You can PLAY sharp, flat and dotted notes by
preceding the notes within quotes with the fol
lowing characters:
#-Sharp
$ - Flat
. - Dotted
A dotted note plays one-and-a-half times longer
than a note that is not dotted.
Now try adding sharp, flat and dotted notes with
this statement:
80 PLAY "V1 04 T4 U8 X0 .H C D Q # E F I
$ G A .S # B"
Line 80 PLAYS voice 1 in octave 4 at volume
level 8 with the flute envelope turned on and the
filter turned off. It also PLAYS C and D as dotted
half notes, E and F as sharp quarter notes, G
and A as flat eighth notes and B as a sharp dot
ted sixteenth note. You can add rests (R) at any
place within your PLAY string. The spaces in the
new PLAY statement examples are not neces
sary. They are used only for readability.
Up until now your statement examples have left
the filter off within the sound synthesizer and
have not realized the true power behind it. Now
that you have digested most of the sound and
music statements and the SID control charac
ters, move on to the next section to Jearn how to
enhance your musical quality with the FILTER
statement.
The SID Filter
Once you have selected the ENVELOPE, ADSR,
VOLume and TEMPO, use the FILTER to perfect
your synthesized sounds. In your program, the
FILTER statement will precede the PLAY state
ment. First you should become comfortable
with generating the sound and worry about FIL-
TERing last. Since the SID chip has only one
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USING C128 MODE—Sound and Music in C128 Mode