FabFilter

I'm trying to figure out the math with the oscillator detuning parameters and converting the value scale -1 - +1 to musical pitch (approximately). So, if a value of 0.5 = Tritone, what is the closest value for a perfect fifth? a P4? and so on.
I notice in the manual that the detuning parameters are more sensitive around the 0 mark - which makes sense for subtle detuning - but would this have an impact on the tuning ratios?
If anyone could share this formula, I'd appreciate it!
Thanks.
J

To calculate a pitch difference D in cents from the frequency ratio R of a given interval, you have to calculate D = log2(R). But Table 1 below does this for you. Then to convert cents (1200 units per octave) to the FF scale (1 unit per octave), you have to divide by 1200. See Table 1.

Table 1
pure interval ==> size in cents ==> FF value
P5 3/2 ==> 702 ==> .585
P4 4/3 ==> 498 ==> .415
M3 5/4 ==> 386 ==> .322
m6 8/5 ==> 814 ==> .678
m3 6/5 ==> 316 ==> .263
M6 5/3 ==> 884 ==> .737
M2 9/8 ==> 204 ==> .170
see pages.globetrotter.net/roule/temper.htm

And for equal tempered intervals, should you want them, see Table 2.

Table 2
ET interval ==> size in cents ==> FF value
m2 ==> 100 ==> .0833
M2 ==> 200 ==> .167
m3 ==> 300 ==> .250
M3 ==> 400 ==> .333
P4 ==> 500 ==> .417
TT ==> 600 ==> .500
P5 ==> 700 ==> .583
m6 ==> 800 ==> .667
M6 ==> 900 ==> .750
m7 ==> 1000 ==> .833
M7 ==> 1100 ==> .917

If you want other ratios, you'll have to calculate log2 yourself. Here's a handy web tool: www.calculator.com/calcs/calc_sci.html

Excellent! Thanks you very much!

what's the advantage of that scale?
i'm used to semitones and cents....
i would like to have an option where people can switch between modes.
bodan

Yeah this synth totally needs that I have been confused using it. Please add cents and sem-tones.

I don't see why semitones + cents would be much of an improvement. Say you want to tune two oscs a pure major third apart. There's nothing especially intuitive about tuning in "4 semitones minus 14 cents". You'd end up using your ears, same as now.

i'm used to semi tones and cents...
why should i "learn" something else?
fabfilter plugins are the only ones i have that use this system....
why?

I say DON'T change or add the feature. Esp. in the case of using an XLFO in Twin 2 to control detuning. It should remain consistent with the rest of the data parameters... IMO.

I would love to see this as a choice, like being able to choose between measuring Semitones/cents and its current setting, since the XLFO needs to flexible enough to be used for any parameter.

It also wouldn't really make as much sense measuring in semitones and cents if the parameter being affected is not directly related to pitch, so again have a choice, like a drop down list or button that swaps the measuring display.

Maybe this can be considered as feature request if it is at all possible? This way I'm sure everyone would be happy.

I think an overall preference setting for how the tuning is displayed (at least on the osc section) would be good. Most people are used to cents and semitones and the fabfilter way does seem a little strange in that light...

OK, we'll consider it for a future update!

Cheers,

thanks....

Good news! We will fix this issue in the upcoming 32/64-bit updates.

Cheers,

Update now released! See www.fabfilter.com/download/index.php?product=8.

Cheers,

thank you very much!!!