frequency other than the ones listed in the note table use "Fout" (frequency output) and the following formula to represent the frequency (Fn) of the sound you want to create. Remember that each note requires both a high and a low frequency number.
Fn = Fout/.06097
Once you've figured out what Fn is for your "new" note the next step is to create the high and low frequency values for that note. To do this you must first round off Fn so that any numbers to the right of the decimal point are left off. You are now left with an integer value. Now you can set the high frequency location (Fhi) by using the formula Fhi=INT(Fn/256) and the low frequency location (Flo) should be Flo=Fn-(256*Fhi).
At this point you have already played with one voice of your computer. If you wanted to stop here you could find a copy of your favorite tune and become the maestro conducting your own computer orchestra in your "at home" concert hall.
Your Commodore computer has three independently controlled voices (oscillators). Our first example program used only one of them. later on, you'll learn how to change the quality of the sound made by the voices. But right now, let's get all three voices singing.
This example program shows you one way to translate sheet music for your computer orchestra. Try typing it in, and then SAVE it on your DATASSETTETM or disk. Don't forget to type NEW before typing in this program.
EXAMPLE PROGRAM 2:
10 S=54272:FORL=STOS+24:POKEL,0:NEXT 20 DIMH(2,200),L(2,200),C(2,200) 30 DIMFQ(11) 40 V(0)=17:V(1)=65:V(2)=33 50 POKES+10,8:POKES+22,128:POKES+23,244 60 FORI=0TO11:READFQ(I):NEXT 100 FORK=0TO2 110 I=0 120 READNM 130 IFNM=0THEN250 140 WA=V(K):WB=WA-1:IFNM<0THENNM=-NM:WA=0:WB=0 150 DR%NM/128:OC%=(NM-128*DR%)/16 160 NT=NM-128*DR%-16*OC% 170 FR=FQ(NT) 180 IFOC%=7THEN200 190 FORJ=6TOOC%STEP-1:FR=FR/2:NEXT 200 HF%=FR/256:LF%=FR-256*HF% 210 IFDR%=1THENH(K,I)=HF%:L(K,I)=LF%:C(K,I)=WA:I=I+1:GOTO120 220 FORJ=1TODR%-1:H(K,I)=HF%:L(K,I)=LF%:C(K,I)=WA:I=I+1:NEXT 230 H(K,I)=HF%:L(K,I)=LF%:C(K,I)=WB 240 I=I+1:GOTO120 250 IFI>IMTHENIM=I 260 NEXT 500 POKES+5,0:POKES+6,240 510 POKES+12,85:POKES+13,133 520 POKES+19,10:POKES+20,197 530 POKES+24,31 540 FORI=0TOIM 550 POKES,L(0,I):POKES+7,L(1,I):POKES+14,L(2,I) 560 POKES+1,H(0,I):POKES+8,H(1,I):POKES+15,H(2,I) 570 POKES+4,C(0,I):POKES+11,C(1,I):POKES+18,C(2,I) 580 FORT=1TO80:NEXT:NEXT 590 FORT=1TO200:NEXT:POKES+24,0 600 DATA34334,36376,38539,40830 610 DATA43258,45830,48556,51443 620 DATA54502,57743,61176,64814 1000 DATA594,594,594,596,596,1618,587,592,587.585,331,336 1010 DATA1097,583,585,585,585,587,587,1609,585,331,337,594,594,593 1020 DATA1618,594,596,594,592,587,1616,587,585,331,336,841,327 1999 DATA1607,0 2000 DATA583,585,583,583,327,329,1611,583,585,578,578,578 2010 DATA196,198,583,326,578,326,327,329,327,329,326,578,583 2020 DATA1606,582,322,324,582,587,329,327,1606,583,327,329,587,331,329 2999 DATA329,328,1609,578,834,324,322,327,585,1602,0 3000 DATA567,566,567,304,306,308,310,1591,567,311,310,567 3010 DATA306,304,299,308,304,171,176,306,291,551,306,308 3020 DATA310,308,310,306,295,297,299,304,1586,562,567,310,315,311 3030 DATA308,313,297,1586,567,560,311,309,308,309,306,308 3999 DATA1577,299,295,306,310,311,304,562,546,1575,0
|This page has been created by Sami Rautiainen.|
|Read the small print.||Last updated February 10, 2002.|