The batari Basic Music and Sound Page

Related bB Programs

 

This page contains adapted information and charts related to Atari 2600 music and sound. It was put together for batari Basic users, but it can be used by assembly programmers too. All information on this page was used with permission.

 

If you haven't tried it yet, check out the Visual batari Basic Music and Sound Editor. Create music and sound effects the fun way. The editor has many cool features and it uses real Atari 2600 sounds.

 

 

 

 

Atari 2600 VCS Distortion Descriptions

The following chart is adapted from Atari 2600 VCS Precise Sound Values and Distortion Breakdown by Glenn Saunders:

Tone	What it Sounds Like
0	No sound (silent).
1	Buzzy tones.
2	Carries distortion 1 downward into a rumble.
3	Flangy wavering tones, like a UFO.
4	Pure tone.
5	Same as 4.
6	Between pure tone and buzzy tone (Adventure death uses this).
7	Reedy tones, much brighter, down to Enduro car rumble.
8	White noise/explosions/lightning, jet/spacecraft engine.
9	Same as 7.
10	Same as 6.
11	Same as 0.
12	Pure tone, goes much lower in pitch than 4 & 5.
13	Same as 12.
14	Electronic tones, mostly lows, extends to rumble.
15	Electronic tones, mostly lows, extends to rumble.

Summary:

Unique Redundant

0 11

1

2

3

4  5

6 10

7  9

8

12 13

14

15

F & W Guide Jump List

Distortion 0

Distortion 1 Keyboard

Distortion 2

Distortion 3

Distortion 4 Keyboard

Distortion 6 Keyboard

Distortion 7 Keyboard

Distortion 8

Distortion 12 Keyboard

Distortion 14 Keyboard

Distortion 15 Keyboard

 

Keyboards Only

 

 

Atari 2600 VCS Sound Frequency And Waveform Guide
(c) copyright by Eckhard Stolberg (Eckhard_Stolberg@web.de)
Based on the version that was last modified on May 25, 2000 (version 1.01)
Adapted by Duane Alan Hahn (with permission)

These tables have been calculated with the information found in Ron Fries' TIASOUND emulation package. Eckhard Stolberg did some sampling on his own to verify it and got basically what Ron's theory suggested. Also he has compared his results with Glenn Saunders' note tables and found them to be almost the same.

 

However, Eckhard Stolberg might have missed something important or simply miscalculated some of the values. Therefore it would be nice, if someone could do some sampling or recalculating to verify or correct these tables.

 

The cent values have been calculated with rounded frequencies. Therefore they are not as accurate as they might look, especially the ones for the lower frequencies.

 

 

 

How the Atari 2600 VCS Produces Sound

The Atari 2600 VCS produces its sound with some shift registers of various lengths. The speed at which it shifts the registers can be set to either the pixelclock/114 or to the CPUclock/114, which means two shifts per scanline or a third of this. Since a NTSC VCS produces 262 scanlines per frame and 60 frames per second this results in output rates of 31440 Hz and 10480 Hz. PAL TVs produce only 312 scanlines and 50 frames, so the output rates are only 31200 Hz and 10400 Hz.

 

A pitch value of n stored in the AUDFx registers modifies the frequency in a way, that n possibilities to shift are left out.

 

The distortion values stored in the AUDCx registers select the clock to use. They also select two shift registers of various lengths. One of these is the source pattern. Every time a 1 is shifted out of the source pattern, the output is set high. If a 0 is shifted out, the output is set low.

 

The other shift register is a clock modifier. Every time a 1 is shifted out, the effect of the source pattern can take place. If a 0 is shifted out, the bit, that is shifted out of the source pattern, has no effect on the output.

 

Since the source pattern and the clock modifier registers match up perfectly except for distortion 2 & 3, my tables only list the resulting output bitstream.

 

More information on the patterns can be found in the documentation for Ron Fries' TIASOUND emulation package.

 

However, since the output switches so fast between high and low, the resulting waveforms are not perfect squarewaves. For example distortion 4 with a pitch value of 0 would flip the output at a rate of 15720 Hz. This is so fast, that the membrane of the speaker couldn't swing very far before it has to change its direction. Therefore no audible sound is produced.

 

 

 

How to Read the Tables

Distortion	Value to be stored in the AUDCx registers.
Waveform	A 1 means the output is set high, a 0 means the output is set low. For distortion 2 & 3 it is source pattern -> clock modifier pattern.
Clockspeed	Speed at which the registers are shifted.
Pitch	Value to be stored in the AUDFx registers.
Note	Note value that is closest to the calculated frequency. (The English notation system is used here. If you are used to the German notation system, please read the 'b' notes as 'h' notes.)
Cent	Percent the calculated frequency is off its corresponding note frequency.
Freq	Frequency that this note would have if A4=440 Hz.
NTSC/PAL	Calculated frequencies for the specified TV norm.

 

Lines marked as below have such a low frequency that it really doesn't matter if it is C or C# rumble.

 

To make it easier for those who want to make music on the Atari 2600, a full size style keyboard-like image with 88 keys is provided for distortions that call for one. Pitches and the percent the pitches are off are displayed on the corresponding keys. Pitches in red are a warning that they may be too far off perfect pitch to be worth using.

 

 

 

Distortion 0 & 11

Waveform	Always high (used to output 4-bit samples by changing the volume very fast)
Clockspeed	pixelclock/114

 

 

 

 

Distortion 1

Waveform	001010000111011
Clockspeed	pixelclock/114

 

NTSC					PAL
Pitch	Note	Cent	Freq	NTSC		Pitch	Note	Cent	Freq	PAL
0	C7	+2	2093	2096		0	C7	-1	2093	2080
1	C6	+2	1046.5	1048		1	C6	-1	1046.5	1040
2	F5	0	698.5	698.7		2	F5	-1	698.5	693.3
3	C5	+2	523.3	524		3	C5	-1	523.3	520
4	G#4	+16	415.3	419.2		4	G#4	+3	415.3	416
5	F4	0	349.2	349.3		5	F4	-13	349.2	346.7
6	D4	+33	293.7	299.4		6	D4	+20	293.7	297.1
7	C4	+3	261.6	262		7	C4	-11	261.6	260
8	A#3	-2	233.1	232.9		8	A#3	-15	233.1	231.1
9	G#3	+15	207.7	209.6		9	G#3	+2	207.7	208
10	F#3	+50	185	190.5		10	F#3	+37	185	189.1
11	F3	+1	174.6	174.7		11	F3	-13	174.6	173.3
12	E3	-39	164.8	161.2		12	D#3	+48	155.6	160
13	D3	+33	146.8	149.7		13	D3	+20	146.8	148.6
14	C#3	+13	138.6	139.7		14	C#3	+1	138.6	138.7
15	C3	+3	130.8	131		15	C3	-11	130.8	130
16	B2	-3	123.5	123.3		16	B2	-16	123.5	122.4
17	A#2	0	116.4	116.4		17	A#2	-14	116.5	115.6
18	A2	+5	110	110.3		18	A2	-8	110	109.5
19	G#2	+16	103.8	104.8		19	G#2	+3	103.8	104
20	G2	+31	98	99.8		20	G2	+17	98	99
21	G2	-49	98	95.3		21	F#2	+36	92.5	94.5
22	F#2	-27	92.5	91.1		22	F#2	-40	92.5	90.4
23	F2	0	87.3	87.3		23	F2	-12	87.3	86.7
24	E2	+29	82.4	83.8		24	E2	+16	82.4	83.2
25	E2	-39	82.4	80.6		25	D#2	+48	77.8	80
26	D#2	-5	77.8	77.6		26	D#2	-18	77.8	77
27	D2	+34	73.4	74.9		27	D2	+20	73.4	74.3
28	D2	-27	73.4	72.3		28	D2	-41	73.4	71.7
29	C#2	+15	69.3	69.9		29	C#2	0	69.3	69.3
30	C#2	-44	69.3	67.6		30	C2	+44	65.4	67.1
31	C2	+3	65.4	65.5		31	C2	-11	65.4	65

 

 

 

 

 

Distortion 2 - 3

Waveform	001010000111011->0100000000000000000100000000000 (465 bits long) 001010000111011->0010110011111000110111010100001 (465 bits long)
Clockspeed	pixelclock/114

 

NTSC					PAL
Pitch	Note	Cent	Freq	NTSC		Pitch	Note	Cent	Freq	PAL
0	C#2	-44	69.3	67.6		0	C2	+44	65.4	67.1
1	C#1	-42	34.6	33.8		1	C1	+42	32.7	33.5
2	F#0	-46	23.1	22.5		2	F0	+46	21.8	22.4
3	C#0	-44	17.3	16.9		3	C0	+44	16.4	16.8
4	below			13.5		4	below			13.4
5				11.3		5				11.2
6				9.7		6				9.6
7				8.5		7				8.4
8				7.5		8				7.5
9				6.8		9				6.7
10				6.1		10				6.1
11				5.6		11				5.6
12				5.2		12				5.2
13				4.8		13				4.8
14				4.5		14				4.5
15				4.2		15				4.2
16				4		16				4
17				3.8		17				3.7
18				3.6		18				3.5
19				3.4		19				3.4
20				3.2		20				3.2
21				3.1		21				3
22				3		22				2.9
23				2.8		23				2.8
24				2.7		24				2.7
25				2.6		25				2.6
26				2.5		26				2.5
27				2.4		27				2.4
28				2.3		28				2.3
29				2.3		29				2.2
30				2.2		30				2.2
31				2.1		31				2.1

 

 

 

 

Distortion 4 & 5

Waveform	01
Clockspeed	pixelclock/114

 

NTSC					PAL
Pitch	Note	Cent	Freq	NTSC		Pitch	Note	Cent	Freq	PAL
0	silent			15720		0	silent			15600
1	B8	-9	7902.1	7860		1	B8	-23	7902.1	7800
2	E8	-11	5274	5240		2	E8	-25	5274	5200
3	B7	-10	3951.1	3930		3	B7	-23	3951.1	3900
4	G7	+4	3136	3144		4	G7	-9	3136	3120
5	E7	-11	2637	2620		5	E7	-25	2637	2600
6	C#7	+21	2217.5	2245.7		6	C#7	+8	2217.5	2228.6
7	B6	-9	1975.5	1965		7	B6	-23	1975.5	1950
8	A6	-13	1760	1746.7		8	A6	-27	1760	1733.3
9	G6	+4	1568	1572		9	G6	-9	1568	1560
10	F6	+39	1396.9	1429.1		10	F6	+25	1396.9	1418.2
11	E6	-11	1318.5	1310		11	E6	-25	1318.5	1300
12	D6	+49	1174.7	1209.2		12	D6	+36	1174.7	1200
13	C#6	+22	1108.7	1122.9		13	C#6	+8	1108.7	1114.3
14	C6	+2	1046.5	1048		14	C6	-11	1046.5	1040
15	B5	-10	987.8	982.5		15	B5	-23	987.8	975
16	A#5	-15	932.3	924.7		16	A#5	-28	932.3	917.6
17	A5	-14	880	873.3		17	A5	-27	880	866.7
18	G#5	-7	830.6	827.4		18	G#5	-20	830.6	821.1
19	G5	+4	784	786		19	G5	-9	784	780
20	F#5	+20	740	748.6		20	F#5	+7	740	742.9
21	F5	+39	698.5	714.5		21	F5	+26	698.5	709.1
22	F5	-38	698.5	683.5		22	E5	+48	659.5	678.3
23	E5	-12	659.3	655		23	E5	-25	659.3	650
24	D#5	+18	622.3	628.8		24	D#5	+5	622.3	624
25	D5	+49	587.3	604.6		25	D5	+36	587.3	600
26	D5	-16	587.3	582.2		26	D5	-29	587.3	577.8
27	C#5	+21	554.4	561.4		27	C#5	+8	554.4	557.1
28	C#5	-40	554.4	542.1		28	C5	+47	523.3	537.9
29	C5	+2	523.3	524		29	C5	-11	523.3	520
30	B4	+45	493.9	507.1		30	B4	+32	493.9	503.2
31	B4	-9	493.9	491.3		31	B4	-23	493.9	487.5

 

 

 

 

 

Distortion 6 & 10 - 7 & 9

Waveform	1111111111111000000000000000000 (6 & 10) 0010110011111000110111010100001 (7 & 9)
Clockspeed	pixelclock/114

 

NTSC					PAL
Pitch	Note	Cent	Freq	NTSC		Pitch	Note	Cent	Freq	PAL
0	B5	+45	987.8	1014.2		0	B5	+32	987.8	1006.5
1	B4	+45	493.9	507.1		1	B4	+32	493.9	503.2
2	E4	+43	329.6	338.1		2	E4	+30	329.6	335.5
3	B3	+45	246.9	253.5		3	B3	+32	246.9	251.6
4	G#3	-42	207.7	202.8		4	G3	+45	196	201.3
5	E3	+43	164.8	169		5	E3	+30	164.8	167.7
6	D3	-23	146.8	144.9		6	D3	-37	146.8	143.8
7	B2	+42	123.5	126.8		7	B2	+32	123.5	125.8
8	A2	+42	110	112.7		8	A2	+28	110	111.8
9	G#2	-41	103.8	101.4		9	G2	+45	98	100.6
10	F#2	-6	92.5	92.2		10	F#2	-19	92.5	91.5
11	E2	+43	82.4	84.5		11	E2	+31	82.4	83.9
12	D#2	+4	77.8	78		12	D#2	-9	77.8	77.4
13	D2	-24	73.4	72.4		13	D2	-37	73.4	71.9
14	C#2	-44	69.3	67.6		14	C2	+44	65.4	67.1
15	B1	+46	61.7	63.4		15	B1	+32	61.7	62.9
16	A#1	+41	58.3	59.7		16	A#1	+26	58.3	59.2
17	A1	+39	55	56.3		17	A1	+27	55	55.9
18	G#1	+48	51.9	53.4		18	G#1	+35	51.9	53
19	G#1	-41	51.9	50.7		19	G1	+45	49	50.3
20	G1	-25	49	48.3		20	G1	-39	49	47.9
21	F#1	-4	46.2	46.1		21	F#1	-20	46.2	45.7
22	F1	+16	43.7	44.1		22	F1	+4	43.7	43.8
23	E1	+44	41.2	42.3		23	E1	+28	41.2	41.9
24	E1	-26	41.2	40.6		24	E1	-39	41.2	40.3
25	D#1	+4	38.9	39		25	D#1	-9	38.9	38.7
26	D1	+41	36.7	37.6		26	D1	+27	36.7	37.3
27	D1	-24	36.7	36.2		27	D1	-38	36.7	35.9
28	C#1	+19	34.6	35		28	C#1	+5	34.6	34.7
29	C#1	-42	34.6	33.8		29	C1	+42	32.7	33.5
30	C1	0	32.7	32.7		30	C1	-11	32.7	32.5
31	B0	+44	30.9	31.7		31	B0	+33	30.9	31.5

 

 

 

 

 

Distortion 8

Waveform	511 bits long (white noise)
Clockspeed	pixelclock/114

 

NTSC					PAL
Pitch	Note	Cent	Freq	NTSC		Pitch	Note	Cent	Freq	PAL
0	B1	-6	61.7	61.5		0	B1	-18	61.7	61.1
1	B0	-6	30.9	30.8		1	B0	-22	30.9	30.5
2	E0	-8	20.6	20.5		2	E0	-17	20.6	20.4
3	below			15.4		3	below			15.3
4				12.3		4				12.2
5				10.3		5				10.2
6				8.8		6				8.7
7				7.7		7				7.6
8				6.8		8				6.8
9				6.2		9				6.1
10				5.6		10				5.6
11				5.1		11				5.1
12				4.7		12				4.7
13				4.4		13				4.4
14				4.1		14				4.1
15				3.8		15				3.8
16				3.6		16				3.6
17				3.4		17				3.4
18				3.2		18				3.2
19				3.1		19				3.1
20				2.9		20				2.9
21				2.8		21				2.8
22				2.7		22				2.7
23				2.6		23				2.5
24				2.5		24				2.4
25				2.4		25				2.3
26				2.3		26				2.3
27				2.2		27				2.2
28				2.1		28				2.1
29				2		29				2
30				2		30				2
31				1.9		31				1.9

 

 

 

 

Distortion 12 & 13

Waveform	10
Clockspeed	CPUclock/114

 

NTSC					PAL
Pitch	Note	Cent	Freq	NTSC		Pitch	Note	Cent	Freq	PAL
0	E8	-11	5274	5240		0	E8	-25	5274	5200
1	E7	-11	2637	2620		1	E7	-25	2637	2600
2	A6	-14	1760	1746.6		2	A6	-27	1760	1733.3
3	E6	-11	1318.5	1310		3	E6	-25	1318.5	1300
4	C6	+2	1046.5	1048		4	C6	-11	1046.5	1040
5	A5	-14	880	873.3		5	A5	-27	880	866.7
6	F#5	+20	740	748.6		6	F#5	+7	740	742.9
7	E5	-12	659.3	655		7	E5	-25	659.3	650
8	D5	-16	587.3	582.2		8	D5	-29	587.3	577.8
9	C5	+2	523.3	524		9	C5	-11	523.3	520
10	A#4	+39	466.2	476.4		10	A#4	+23	466.2	472.7
11	A4	-13	440	436.7		11	A4	-27	440	433.3
12	G4	+48	392	403.1		12	G4	+34	392	400
13	F#4	+20	370	374.3		13	F#4	+6	370	371.4
14	F4	0	349.2	349.3		14	F4	-13	349.2	346.7
15	E4	-11	329.6	327.5		15	E4	-25	329.6	325
16	D#4	-17	311.1	308.2		16	D#4	-30	311.1	305.9
17	D4	-16	293.7	291.1		17	D4	-29	293.7	288.9
18	C#4	-9	277.2	275.8		18	C#4	-22	277.2	273.7
19	C4	+3	261.6	262		19	C4	-11	261.6	260
20	B3	+18	246.9	249.5		20	B3	+5	246.9	247.6
21	A#3	+37	233.1	238.2		21	A#3	+24	233.1	236.4
22	A#3	-40	233.1	227.8		22	A3	+47	220	226.1
23	A3	-14	220	218.3		23	A3	-27	220	216.7
24	G#3	+15	207.7	209.6		24	G#3	+2	207.7	208
25	G3	+47	196	201.5		25	G3	+34	196	200
26	G3	-17	196	194.1		26	G3	-31	196	192.6
27	F#3	+19	185	187.1		27	F#3	+6	185	185.7
28	F#3	-41	185	180.7		28	F3	+45	174.6	179.3
29	F3	+1	174.6	174.7		29	F3	-13	174.6	173.3
30	E3	+43	164.8	169		30	E3	+30	164.8	167.7
31	E3	-11	164.8	163.8		31	E3	-25	164.8	162.5

 

 

 

 

 

Distortion 14 - 15

Waveform	1111111111111000000000000000000 (14) 0010110011111000110111010100001 (15)
Clockspeed	CPUclock/114

 

NTSC					PAL
Pitch	Note	Cent	Freq	NTSC		Pitch	Note	Cent	Freq	PAL
0	E4	+43	329.6	338.1		0	E4	+30	329.6	335.5
1	E3	+43	164.8	169		1	E3	+30	164.8	167.7
2	A2	+42	110	112.7		2	A2	+28	110	111.8
3	E2	+43	82.4	84.5		3	E2	+31	82.4	83.9
4	C#2	-44	69.3	67.6		4	C2	+44	65.4	67.1
5	A1	+39	55	56.3		5	A1	+27	55	55.9
6	G1	-25	49	48.3		6	G1	-39	49	47.9
7	E1	+44	41.2	42.3		7	E1	+28	41.2	41.9
8	D1	+41	36.7	37.6		8	D1	+27	36.7	37.3
9	C#1	-42	34.6	33.8		9	C1	+42	32.7	33.5
10	B0	-11	30.9	30.7		10	B0	-22	30.9	30.5
11	A0	+44	27.5	28.2		11	A0	+31	27.5	28
12	G#0	0	26	26		12	G#0	-13	26	25.8
13	G0	-29	24.5	24.1		13	G0	-36	24.5	24
14	F#0	-46	23.1	22.5		14	F0	+46	21.8	22.4
15	E0	+42	20.6	21.1		15	E0	+33	20.6	21
16	D#0	+42	19.4	19.9		16	D#0	+25	19.4	19.7
17	D0	+40	18.4	18.8		17	D0	+20	18.4	18.6
18	C#0	+45	17.3	17.8		18	C#0	+36	17.3	17.7
19	C#0	-44	17.3	16.9		19	C0	+44	16.4	16.8
20	C0	-30	16.4	16.1		20	C0	-40	16.4	16
21	below			15.4		21	below			15.2
22				14.7		22				14.6
23				14.1		23				14
24				13.5		24				13.4
25				13		25				12.9
26				12.5		26				12.4
27				12.1		27				12
28				11.7		28				11.6
29				11.3		29				11.2
30				10.9		30				10.8
31				10.6		31				10.5

 

 

 

 

 

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