SynthMakerunkargherth ·
I think it would be useful to know what is the exact mapping between areal Freq (IN hZ) and the freq param used in SM
Also would be useful to have the formulae/table used to convert from pitch to freq
conversion formulae
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Sk ·
If you need to know the frequency values associated to the notes, you just need a couple of hints: - A3 is 440 Hz - each note frequency is the previous one times 2^(1/12), ie twelve root of two. For example, Bb3 is 440 * 2^(1/12). This way, A4 is 2*A3=880 Hz, and so on. A perfect fifth is 3/2, so G=1.5*C. If I'm not wrong, it is interesting to know that the hearable range (16 Hz - 20 kHz) is made up of 128 notes, which exactly fits for a binary representation. So, one could say that MIDI was in the order of the real since the Creation 🙂
unkargherth ·
Already know thjis SK, What i'm asking for is how to convert 440 HZ to the 0..1 scale used in freq/pitch inside SM ( and how to deconvert back)
Shifrin ·
Umm, maybe I misunderstand but isn't the freq value in SM simply the Hz value, i.e. 440Hz = 1/440 = 0.002272727...
And the pitch value is the midi note number, so a C3 = 60 (IIRC) hence C#3 = 61, D3 = 62 etc. So if you want to transpose up an octave from the incoming pitch you simply add 12 (has to be a float value though doesn't work with ints).
If I've misunderstood then sorry!!!
Shif.
stefan ·
Shifrin wrote: Umm, maybe I misunderstand but isn't the freq value in SM simply the Hz value, i.e. 440Hz = 1/440 = 0.002272727...
And the pitch value is the midi note number, so a C3 = 60 (IIRC) hence C#3 = 61, D3 = 62 etc. So if you want to transpose up an octave from the incoming pitch you simply add 12 (has to be a float value though doesn't work with ints).
If I've misunderstood then sorry!!!
Shif.
No, freq is. hm. I think it is frequency normalized to nyquist, that is: FrequencyInHz / Nyquist, so for instance in 44khz 0..22050 hz maps to 0..1 SM-freq-units.
Pitch I dunno though. Pitch is a normal scale, but I don't know where it starts (which note that is 0), because I haven't looked at it 🙂
Shifrin ·
stefancrs wrote: No, freq is. hm. I think it is frequency normalized to nyquist, that is: FrequencyInHz / Nyquist, so for instance in 44khz 0..22050 hz maps to 0..1 SM-freq-units.
That's interesting to know, thanks!
stefancrs wrote: Pitch I dunno though. Pitch is a normal scale, but I don't know where it starts (which note that is 0), because I haven't looked at it 🙂
C-2 is 0 iirc, so five octaves up you get C3 (60). I'm sure that's how the pitch value works I seem to remember asking Jorge about it!
Shif.
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