5 S=54272
 10 FORL=STOS+24:POKEL,0:NEXT
 15 POKES+22,128:POKES+21,0:POKES+23,1
 20 POKES+5,9:POKES+6,0
 30 POKES+24,79
 40 READHF,LF,DR
 50 IFHF<0THENEND
 60 POKES+1,HF:POKES,LF
 70 POKES+4,33
 80 FORT=1TODR:NEXT
 90 POKES+4,32:FORT=1TO50:NEXT
 100 GOTO40
 110 DATA25,177,250,28,214,250
 120 DATA25,177,250,25,177,250
 130 DATA25,177,125,28,214,125
 140 DATA32,94,750,25,177,250
 150 DATA28,214,250,19,63,250
 160 DATA19,63,250,19,63,250
 170 DATA21,154,63,24,63,63
 180 DATA25,177,250,24,63,125
 190 DATA19,63,250,-1,-1,-1

Try RUNning the program now. Notice the lower tones have had their volume cut down. It makes the overall quality of the note sound tinny. This is because you are using a high-pass filter which attenuates (cuts down the level of) frequencies below the specified cutoff frequency.

There are three types of filters in your Commodore computer's SID chip. We have been using the high-pass filter. It will pass all the frequencies at or above the cutoff, while attenuating the frequencies below the cutoff.