--------------------------ATARI 2600 VCS PRECISE SOUND VALUES------------------- ------------------------------AND DISTORTION BREAKDOWN-------------------------- -------------------------------------------------------------------------------- ---------------------------------BY GLENN SAUNDERS------------------------------ -------------------------------LAST REVISION 4/2/97---------------------------- -------------------------------------------------------------------------------- The Atari 2600 (and the Atari 8-bit) produces tones based on polynomial counters. Because of this, a great many of the notes are "out of tune" (although it's a lot worse on the 2600 than the 8-bit, which is why 7800 Ballblazer has POKEY on board, for instance.) N ot only that, but there are some intervals between notes in all of the distortions at the upper- register which will make slim pickings up there, and some of the notes are spread between two different distortions like a jigsaw puzzle. These charts were created for programmers to consult so that they can compose music that only uses notes that are in tune. To my ears, this means no more than 10 "cents" off perfect pitch (relative to other notes). One important thing I have to add is octave values, but I don't have a keyboard and no way of knowing what "C1" is so this will have to wait unless someone else would like to revise it. The process by which music can be composed is tricky. It will require you to build additional charts off this one that group notes based on how "in tune" they are in relation to eachother. For instance, you could sort out all the notes that are between +40 and +50 cents out of tune. Then you will figure out which group of notes provides you with the largest variety of notes. Then you will attempt to take your standard notation and transpose it as best you can to conform it to the available notes without resulting in "unattainable" notes. The only analogy I can think of is a DULCIMER, which is fretted so that only the major diatonic scale can be played, which limits you to only one key. You can't play a chromatic scale with a dulcimer, and you aren't likely to be able to play many well-tempered notes close to eachother on the 2600 either. Another thing that makes it tricky is the crossover between X# -50 and X +50. Just be aware that the two notes in this example are VERY close in pitch when sorting and building new charts. If you do build a chart that crosses over like this, you'll probably have to convert one to the other in order to make workable music. Music that will translate well to the 2600 will probably use lots of octaves and fifths, since there are plenty of those (in tune) in all pitches. REVISION HISTORY 4-1-97 First revision. There is a good chance some of the notes may be off due to the chromatic tuner returning the value of overtones and not the fundemental. I did the best I could with it. There is some room for improvement as well as picking some more notes out of the bassy "rumble" areas. --Glenn Saunders ------------------------------------------------------------------------------- CHART KEY---------------------------------------------------------------------- COLUMNS=Distortion value (decimal) and variation from perfect pitch in CENTs. Values containing ? = unknown. Values qualified with an additional ? means best-guess. ROWS=Note values (decimal). ===========================THE 2600 NOTE CHART================================= NOTE 1 1 CENT 2 2 CENT 3 3 CENT ---------- ------- ------- ---------- ---------- ---------- ---------- 00 C -5 C# -50 C# -50 01 C -5 C# -50? C# -50? 02 F -5 F# -50? F# -50? 03 C 0 C# -50? C# -50? 04 G# +11 B -50? B -50? 05 F -5 D# ? D# ? 06 D +30 C# -50? C# -50? 07 C 0 B? ? B ? 08 A# -8 C# -50? C# -50? 09 G# +10 MED RUMBLE G# +40? 10 F# +50 RUMBLE G 0? 11 F -5 RUMBLE F 0? 12 E -50 RUMBLE E -40? 13 D +30 RUMBLE D +30? 14 C# +10 RUMBLE C# +50? 15 C 0 RUMBLE C# -50? 16 B -10 RUMBLE B +25? 17 A# -10 RUMBLE A# +10? 18 A 0 RUMBLE A +30 19 G# +10 RUMBLE G# +40 20 G +30 RUMBLE G +50 21 F# +50 RUMBLE G -20 22 F# -30 RUMBLE F# 0 23 F -5 RUMBLE F +20? 24 E +30 RUMBLE F -50? 25 E -50 RUMBLE E -30? 26 D# -10 RUMBLE D# -20? 27 D +35 RUMBLE D +30 28 D -32 RUMBLE D 0? 29 C# +10 RUMBLE C# 0? 30 C# -50 LOW RUMBLE C# -30? 31 C1? 0 C#? -50? C# -50? NOTE 4 AND 5 4&5 CENTS 6 AND 10 6&10 CENTS 7 AND 9 8 ---------- ---------- ---------- ---------- ---------- ---------- ---------- 00 SILENT B +40 SAME AS 6 WHITE NOISE 01 B ? B +40 DIFF DIST HIGH 02 E ? E +40 HIGH 03 B ? B +40 HIGH 04 G ? G# -50 HIGH 05 E ? E +40 HIGH 06 C# ? D -30 HIGH 07 B ? B +40 HIGH 08 A ? A +40 HIGH 09 G ? G# +40 HIGH 10 F +50 F# -10 MED 11 E -20 E +40 MED 12 D 0 D# 0? MED 13 C# +20 D -40 MED 14 C -5 C# -40? MED 15 B -15 B +40? MED 16 A# -20 A# +50? MED 17 A -20 A +50? MED 18 G# -15 G# +50 MED 19 G 0 G# -50? LOW 20 F# +15 G -40? LOW 21 F +40 F# -20? LOW 22 F -50 F 0? LOW 23 E -20 E +30 LOW 24 D# +15 E -50? LOW 25 D +50 D# -20? LOW 26 D -20 D +30? LOW 27 C# +20 D 0? LOW 28 C# -50 C# +30 LOW 29 C 0 C# -20? LOW 30 B +50 B 0? LOW 31 B -15 B +40 LOW NOTE 12 AND 13 12&13 CNTS 14 14 CENT 15 ---------- ---------- ---------- ---------- ---------- ---------- 00 A -20? E +40 SAME AS 14 01 E -40? E +40 DIFF DIST 02 A -20 A +40 03 E -10? E +40 04 C 0? C# -50 05 A -40 A +40 06 F# +10 G -50? 07 E -20 E +40 08 D -20 D +50? 09 C 0 C# -50 10 A# +30 B 0? 11 A -20 A 0? 12 G +50 G# 0? 13 F# +20 G -20 14 F 0? F +20? 15 E -20 MED BUZZ 16 D# -20 BUZZ 17 D -20 BUZZ 18 C# -15 BUZZ 19 C 0 BUZZ 20 B +15 BUZZ 21 A# +32 BUZZ 22 A# -50 BUZZ 23 A -20 BUZZ 24 G# +10 BUZZ 25 G +50 BUZZ 26 G -25 BUZZ 27 F# +15 BUZZ 28 F# -50 BUZZ 29 F 0 BUZZ 30 E +50 BUZZ 31 E -20 LOW BUZZ ATARI 2600 VCS DISTORTION DESCRIPTIONS (XX & YY = exactly the same notes&dist.) -------------------------------------- DECIMAL DISTORTION VALUE WHAT IT SOUNDS LIKE ---------- --------------------- 00 & 11 TOTALLY SILENT 01 Buzzy tones 02 Carries distortion 1 downward into a rumble. 03 Flangy wavering tones, like a UFO 04 & 05 Pure tones 06 & 10 Inbetween pure tone and buzzy tones (Adventure death uses this) Maybe filters off the highs here 07 & 09 Reedy tones, much brighter, down to Enduro car rumble 08 White noise/explosions/lightning, jet/spacecraft engine 12 & 13 Pure tones, goes much lower in pitch than 04 & 05. 14 Electronic tones, mostly lows, extends to rumble. 15 Electronic tones, mostly highs, extends to rumble. -- Archives available at http://www.biglist.com/lists/stella/archives/ E-mail UNSUBSCRIBE in the body to stella-request@biglist.com to be removed.