[Prev] [Next] [Contents] [Commodore] [New] [Search] [Home]

Change the waveform to square and try a piano type sound with these lines:

   15 POKES+3,8:POKES+2,0
   20 POKES+5,9:POKES+6,0: REM A=0;D=9;S=0;R=0
   70 POKES+4,65
   90 POKES+4,64:FORT=1TO50:NEXT

The most exciting sounds are those unique to the music synthesizer itself, ones that do not attempt to mimic acoustic instruments. For example try:

   20 POKES+5,144:POKES+6,243:REM A=9;D=O; S=15;R=3


The harmonic content of a waveform can be changed by using a filter. The SID chip is equipped with three types of filtering. They can be used separately or in combination with one another. Let's go back to the sample program you've been using to play with a simple example that uses a filter. There are several filter controls to set.

You add line 15 in the program to set the cutoff frequency of the filter. The cutoff frequency is the reference point for the filter. You SET the high and low frequency cutoff points in registers 21 and 22. To turn ON the filter for voice 1, POKE register 23.

Next change line 30 to show that a high-pass filter will be used (see the SID register map).

[Prev] [Next] [Contents] [Commodore] [New] [Search] [Home]
This page has been created by Sami Rautiainen.
Read the small print. Last updated February 10, 2002.