Frequency bands

Different vocoders use different bands (see this spreadsheet for some numbers). Bands are stated in frequency, but it would be more logical to arrange bands in notes, as vocoders will devide the frequency domains in a exponentials scale. The GRP, for example devides the range F#3 to A8 into equal notes, spaced 3 semitones apart (using F#, A, C and D#). The Moog devides the range D#3 to D#8 into equal notes, spaces 4 semitones apart (using D#, G and B). Interestingly, the 2504 Hz channel is a bit off: it should be 2540 Hz (!).

So, lets have a frequency range spaced 4 semitones apart (using A, C# and F) and have 16 channels (NB: calculations are made using just intonation! - Maybe better to use equal temperment?)

Band	Note	Frequency just	Frequency equal
LP	F3+	176	175
1	A3	220	220
2	C#4-	275	277
4	F4+	352	349
3	A4	440	440
5	C#5-	550	554
7	F5+	704	698
6	A5	880	880
8	C#6-	1100	1109
9	F6+	1408	1397
10	A6	1760	1760
11	C#7-	2200	2217
12	F7+	2816	2794
13	A7	3520	3520
14	C#8-	4400	4435
15	F8+	5632	5588
HP	A8	7040	7040