Samplers on ACiD

WinstonSmith

Member

Emu cords: pitch bend percentages conversion to semitones

Greetings (bow)

I'm all happy using the cords but the thing that stumps me is if I put in a pitch bend of say +10% over 2 bars, how many semitones am I shifting up?

Until now I have just been doing it by ear but then I found this thread on samplersonacid and it was explained really nice and simple:

http://samplersonacid.com/legacy-emus-o … 3.php.html

Conclusion: 3% = 1 semitone. So 36% = 1 octave etc... fine. Cheers.

But then I see this other post where it's explained in a much more detailed way - which may mean it's more accurate(?). Unfortunately my brain is quite small and so I need a hand from you clever people to decode what's being suggested if you have a spare few minutes?

http://samplersonacid.com/legacy-emus-o … 0.php.html

"for simplicity [LOL!] lets use the midi cc A as your pitching up, and your midi cc B as your pitching down. this is how the values in of your cc would match up with the pitches of the diatonic scale. of course the values would be the same going up and down.

given the pitch cord is set to 36%, the following should be true.

for a half step transition, midi cc should be either 10 or 11, it actualy is 10.583333 blah blah blah.

for a whole step transistion, midi cc should be 21. (eh, what can you say, it isn't the most accurate controller.. but really you want hear too much difference)

so the values for the cc for a major scale would follow approximately:

tonic>0 "C"
supertonic>21 "D"
median>42 "E"
subdominate>52 "F"
dominate>73 "G"
submedian>94 "A"
leading tone>115 "B"
octave>125 "C"

<end quote>"

So what's he saying? Set up a different midi cc number for different levels of pitch shift? I really can't get my head around it.

I prefer the first guy's method..... if you have an original note at C and want to bend up to d#, then set the percentage to +9%. (If you could confirm my understanding here is correct too I'd be really grateful!)

Thanks in advance, more thanks will come I am sure!

philtipping

Administrator

Re: Emu cords: pitch bend percentages conversion to semitones

No takers yet so I'll add my 2 cents. You need 38% for a shift of 12 semitones, which works out at (38 / 12) = approx 3.16% per semitone. This gives:
1 x 3.16 = 3.16 ~ 3%
2 x 3.16 = 6.33 ~ 6%
3 x 3.16 = 9.5 ~ 9%/10%
4 x 3.16 = 12.67 ~ 13%
etc
7 x 3.16 = 22.17 ~ 22%
etc
12 x 3.16 = 38 ~ 38%
This is effectively using the first method where the shift is in semitones regardless of scale. I think the 2nd method is showing how you can get specific notes in a scale by using a cc controller instead of a pitch wheel to give more controllability.
To answer your original question, 1% = (12 / 38) = approx 0.316 semitones, so 10% is 3.16 semitones.

Footnote: seemed odd that the same digits 3,1,6 appear in both 38/12 and 12/38 so made me double-check the maths. Turns out 3.16 x 3.16 = approx 10, so it's right! - coincidence or what?

Last edited by philtipping (2015-08-16 10:26:47)

WinstonSmith

Member

Re: Emu cords: pitch bend percentages conversion to semitones

Thanks!

On the second method, how would this be implemented?  Something like this:

1) Setup Midi A to control pitch (up) in the cords screen
2) Put in a midi note on the piano roll which is the same as the original note you sampled at, running the length at one or two bars.
--- assuming you want to pitchbend an octave ---
3) In the automation lane set the CC assigned to Midi A to go from 0 to 127 by the end of the bar?

Thanks again!

philtipping

Administrator

Re: Emu cords: pitch bend percentages conversion to semitones

Seems ok to me but not tried it myself; let us know if it works

Update - just tried it - works a treat!

Last edited by philtipping (2015-08-16 12:38:24)

WinstonSmith

Member

Re: Emu cords: pitch bend percentages conversion to semitones

Excellent!  i had to disconnect and rearrange my studio 2 weeks back and will only get a  chance to reassemble it all this weekend, so really looking forward to trying it.  Glad it worked for you! 

Cheers :]