It's no secret I love C64 SID music, and the High Voltage SID Collection is absolutely awesome but there is one SID that comes to mind that sounds different in all SID players, even on a real C64 than it did when I fist heard it. The reason being there was a BASIC program randomising the tone of one of the channels! Here is how it should sound, and as filters are not in use, emulation captures it perfectly.

There's a good example of how it's heard through a SID player on the Unepic SID Channel so you can listen to that at you own leisure, and it can be found here: https://www.youtube.com/watch?v=Q_wFyU6_xm0

This is the BASIC program. PETSCII graphics converted to full stops for ASCII compatibility.

10 TI$="000000":SYS4104:SYS7155:POKE808,234:POKE681,70
50 POKE 53280,15:POKE 53281,15:PRINT".";
52 PRINT". .THE MIGHTY"
54 PRINT""
56 PRINT" ....... .................."
58 PRINT" . .. .. .... .... .."
60 PRINT" .. .. .. .... .................."
62 PRINT" .. .. .. .... ...... ....... .... ...."
64 PRINT" .... . .... .. .. .... ...... .. ...... .. .. .. .."
66 PRINT". . ... . .... ..... ......... ......... .. .. .."
68 PRINT". ..... .. ..... .... .... .... .. ......"
70 PRINT" .. ..... .... .... .... .."
72 PRINT" ...................................... .."
74 PRINT" .... .... .... .... .. .."
76 PRINT" .... .... .... .. .."
78 PRINT" .... .... .. .."
80 PRINT" .... ....."
82 PRINT" .... IS HERE! ...."
84 PRINT" .... ...."
85 PRINT". 'LETTUCE'..WRITTEN & ARRANGED BY BOGG"
86 PRINT" ON FEBRUARY THE 1ST 1986"
90 IFPEEK(960)＜＞32THENGOSUB1000
100 S=54274:X=150:L=960
110 FORT=300TO4000STEPX:SYSL,S+7,T:SYSL,S+14,T/2:POKES-1,RND(0)*120:NEXT
120 FORT=4000TO300STEP-X:SYSL,S+7,T:SYSL,S+14,T/2:POKES-1,RND(0)*120:NEXT
125 IFVAL(TI$)＞152THENRUN
130 GOTO110
1000 FORI=960TO999:READZ:POKEI,Z:NEXT:RETURN
1001 DATA32,253,174,32,138,173,32,247
1002 DATA183,165,20,133,253,165,21,133
1003 DATA254,32,253,174,32,138,173,32
1004 DATA247,183,160,0,165,20,145,253
1005 DATA160,1,165,21,145,253,96,0