NES APU Note Table

The NES RP2A03 CPU clock runs at 1.789773MHz (NTSC). In producing audio, the wave period of the pulse ("square wave") channels is specified in timer units of 16 clock cycles. This means the period is quantized to units of 16/1,789,773 second. The triangle channel, usually used for bass lines, uses 32-cycle timer units, so for a given timer period, it's an octave lower than the pulse channels.

The pulse channels are incapable of producing a note lower than A1, with a timer period of 2033, because the timer period is represented by 11 bits, giving a maximum value of 2048.

This table shows the closest timer period for each note. It becomes less inaccurate, especially for the triangle channel, in the higher register.

Note Name MIDI Note Frequency Piano Note APU Index Pulse Period Tuning (Cents) Triangle Period Tuning (Cents)
A0 21 27.5 1       2033 0
A#0 22 29.1352 2       1919 0
B0 23 30.8677 3       1811 0
C1 24 32.7031 4 0     1709 0
C#1 25 34.6478 5 1     1613 0
D1 26 36.708 6 2     1523 0
D#1 27 38.8908 7 3     1437 0
E1 28 41.2034 8 4     1356 1
F1 29 43.6535 9 5     1280 0
F#1 30 46.2493 10 6     1208 0
G1 31 48.9994 11 7     1140 1
G#1 32 51.913 12 8     1076 1
A1 33 55 13 9 2033 0 1016 0
A#1 34 58.2704 14 10 1919 0 959 0
B1 35 61.7354 15 11 1811 0 905 0
C2 36 65.4063 16 12 1709 0 854 0
C#2 37 69.2956 17 13 1613 0 806 0
D2 38 73.4161 18 14 1523 0 761 0
D#2 39 77.7817 19 15 1437 0 718 0
E2 40 82.4068 20 16 1356 1 678 -1
F2 41 87.307 21 17 1280 0 640 -1
F#2 42 92.4986 22 18 1208 0 604 -1
G2 43 97.9988 23 19 1140 1 570 -1
G#2 44 103.8261 24 20 1076 1 538 -1
A2 45 110 25 21 1016 0 507 2
A#2 46 116.5409 26 22 959 0 479 0
B2 47 123.4708 27 23 905 0 452 0
C3 48 130.8127 28 24 854 0 427 -2
C#3 49 138.5913 29 25 806 0 403 -2
D3 50 146.8323 30 26 761 0 380 0
D#3 51 155.5634 31 27 718 0 359 -2
E3 52 164.8137 32 28 678 -1 338 2
F3 53 174.6141 33 29 640 -1 319 2
F#3 54 184.9972 34 30 604 -1 301 2
G3 55 195.9977 35 31 570 -1 284 2
G#3 56 207.6523 36 32 538 -1 268 2
A3 57 220 37 33 507 2 253 2
A#3 58 233.0818 38 34 479 0 239 0
B3 59 246.9416 39 35 452 0 225 4
C4 60 261.6255 40 36 427 -2 213 -2
C#4 61 277.1826 41 37 403 -2 201 -2
D4 62 293.6647 42 38 380 0 189 4
D#4 63 311.1269 43 39 359 -2 179 -2
E4 64 329.6275 44 40 338 2 169 -3
F4 65 349.2282 45 41 319 2 159 2
F#4 66 369.9944 46 42 301 2 150 2
G4 67 391.9954 47 43 284 2 142 -4
G#4 68 415.3046 48 44 268 2 134 -4
A4 69 440 49 45 253 2 126 2
A#4 70 466.1637 50 46 239 0 119 0
B4 71 493.8833 51 47 225 4 112 4
C5 72 523.2511 52 48 213 -2 106 -2
C#5 73 554.3652 53 49 201 -2 100 -2
D5 74 587.3295 54 50 189 4 94 4
D#5 75 622.2539 55 51 179 -2 89 -2
E5 76 659.2551 56 52 169 -3 84 -3
F5 77 698.4564 57 53 159 2 79 2
F#5 78 739.9888 58 54 150 2 75 -10
G5 79 783.9908 59 55 142 -4 70 8
G#5 80 830.6093 60 56 134 -4 66 9
A5 81 880 61 57 126 2 63 -12
A#5 82 932.3275 62 58 119 0 59 0
B5 83 987.7666 63 59 112 4 56 -11
C6 84 1046.5022 64 60 106 -2 52 14
C#6 85 1108.7305 65 61 100 -2 49 15
D6 86 1174.659 66 62 94 4 47 -14
D#6 87 1244.5079 67 63 89 -2 44 -2
E6 88 1318.5102 68 64 84 -3 41 17
F6 89 1396.9129 69 65 79 2 39 2
F#6 90 1479.9776 70 66 75 -10 37 -10
G6 91 1567.9817 71 67 70 8 35 -16
G#6 92 1661.2187 72 68 66 9 33 -17
A6 93 1760 73 69 63 -12 31 -12
A#6 94 1864.655 74 70 59 0 29 0
B6 95 1975.5332 75 71 56 -11 27 19
C7 96 2093.0045 76 72 52 14 26 -18
C#7 97 2217.461 77 73 49 15 24 15
D7 98 2349.3181 78 74 47 -14 23 -14
D#7 99 2489.0158 79 75 44 -2 21 37
E7 100 2637.0204 80 76 41 17 20 17
F7 101 2793.8258 81 77 39 2 19 2
F#7 102 2959.9553 82 78 37 -10 18 -10
G7 103 3135.9634 83 79 35 -16 17 -16
G#7 104 3322.4375 84 80 33 -17 16 -17
A7 105 3520 85 81 31 -12 15 -12
A#7 106 3729.31 86 82 29 0 14 0
B7 107 3951.0664 87 83 27 19 13 19
C8 108 4186.009 88 84 26 -18 12 47
C#8 109 4434.922   85 24 15    
D8 110 4698.6362   86 23 -14 11 -14
D#8 111 4978.0317   87 21 37 10 37
E8 112 5274.0409   88 20 17    
F8 113 5587.6517   89 19 2 9 2
F#8 114 5919.9107   90 18 -10    
G8 115 6271.9269   91 17 -16 8 -16

Source spreadsheet on Google Sheets: NES APU Note Table

Leave a Reply