Changing Pitch in Amazing Slow Downer
How many semitones does it take to go from a D to a C?
So, two semitones equals a whole key drop, or vice versa? How many to go from a C to a B flat?
Here is the chromatic scale: A A#/Bb B C C#/Db D D#/Eb E F F#/Gb G G#/Ab A. Each one of these notes/keys are one semitone (half step) away from each other. So, from C to Bb is two semitones.
... that you have to accept. There are many valid reasons for the way notes are laid out, but it is confusing.
The only way to be precise in talking about the "distance" between notes is by talking about the number of half steps. That is why Amazing Slowdowner allows pitch shifting in half-steps or "semi-tones."
The Chromatic scale Dave mentions is the scale of every note available to us (on a piano). There are 12 unique notes (per octave). Each of these is one semi-tone away from the next.
In case it helps..... For a very, very, very long time I just assumed that the white keys were all a whole note apart, the black keys were sharps and flats, and any note with a name that didn't have a sharp or flat by it must be a whole step away from the next. Had I learned to play piano at an early age (or ever for that matter) I now know I would be much wiser.
Here's the deal - a major scale is NOT separated by all whole notes. The C major scale is the only one without sharps or flats so it is easiest to write: C D E F G A B C. Now, if you look on a piano, you'll see that there's no black key between E and F, nor is there one between B and C. Listen to those notes - try to sing a half step between them - bet you can't! B and C are only a semi-tone apart! (So are E and F.)
You can start on ANY key on the piano, and if you go up by: STARTING NOTE, Whole-step, Whole-step, HALF-step, Whole-step, Whole-step, HALF-step, Whole-step you'll hear a major scale just like the C scale above. It is very precise to talk about the number of whole and half steps - and that works in any key.
The confusion continues. For example, intervals are called "thirds" and "fifths" and the like. But what's a third? The simple answer is "separated by 3 notes" - E is a third above C. Well - in all honesty, that answer isn't complete. Here's a precise answer: A MAJOR third is 5 half steps. A MINOR third is 4 half steps.
I didn't write the rules, but sometimes it really is easier to think of the number of semi-tones between notes or intervals.
And THAT may be way more information than you wanted.
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