I have played drums and guitar for 25 years and never “got into” music theory. I know what sounds good and play that but I never learned the names or theory behind it.
Why is a 5th not 5 notes apart? On a keyboard it’s any where from 4 white keysto 8 total keys? Why is there not uniformity or consistency?
In: 0
It is five notes – on the scale – which is determined by the notes being more than one piano key/guitar fret from each other.
For instance, a C Major scale goes C,D,E,F,G,A,B,C. If you play the first note (C) with the fifth note in the scale (G), you have your “Fifth”.
There is. A fifth is uniformly, and consistently, two notes whose frequencies are a ratio of 3:2. On a piano this will always be 8 total keys (combination of black and white).
As an example this can be C to G (C, C#, D, D#, E, F, F#, G)
Or it could be A# to F (A#, B, C, C#, D, D#, E, F)
It is usually much easier to explain music theory on a guitar. On a guitar a fifth is always eight frets higher. And that is the same for a piano, it is eight keys up. The reason it is called a fifth is because it is five notes up. On a regular piano the notes on the C-major scale or A-minor scale is white and the others black. So if you start with a C and want the fifth you count up from C being 1 and end up on G being 5 which is the fifth.
However say you start with A#. So you start counting A# is 1, C is 2 because that is the next note in the A#-major scale, you skip B because it is not in the A#-major scale. D is 3, D# is 4 as this is the next note in the scale. Then you skip E so F is 5. That means that F is the fifth note up from A#. You can use the minor scale as well if you want, for fifth it does not matter but for third it does.
When writing music, you start with a repertoire of notes to choose from, called a scale. Many different scales have been used by different cultures, genres, and composers, but the most common scales used in modern Western music, such as the major scale and the harmonic minor scale, have three notes in between the starting note and the fifth (whose frequency is approximately 1.5 times that of the starting note).
> On a keyboard it’s any where from 4 white keysto 8 total keys? Why is there not uniformity or consistency?
The keyboard is designed so that the notes from the C major scale are on white keys, and the rest are on black keys. Each pair of adjacent keys (e.g. C to C#, or E to F) have frequencies in a fixed ratio (the twelfth root of 2, to be precise). So the black keys aren’t any different from the white keys – they’re just arranged like that for convenience.
It is five scale steps apart. And when we notate music on the staff, a fifth spans an interval of five notes (inclusive).
A piano can play the scale in any tonality. Each tonality only uses 7 of the possible 12 equal-tempered pitch classes to form its scale. For example, the scale of G Major does not use c-sharp, but the scale of A Major does. G Major uses f-sharp, but C Major does not. You could build a keyboard with only white keys, but then you could only play music in C Major/a minor and the related modes.
>On a keyboard it’s any where from 4 white keysto 8 total keys? Why is there not uniformity or consistency?
I’m not sure where you’re getting confused here, it’s always ‘8 keys’. Depending on where you start from the run of 8 keys can start and end on white keys that are 4 apart but they are still a total of 8 keys. It’s perfectly consistent.
Are you just confused about why it’s called a fifth?
A fifth is called that because it’s the fifth scale degree in a major scale. The fifth of any note is always seven semitones (frets) higher. On a guitar, because most strings are tuned a fourth apart, an open string and the second fret on the next string are a fifth apart (0 on the G string and 3 on the B is the only exception because B is only a third above G).
One way to think about it is that if you choose a note to be your main note, not all other notes will sound nice with it. One theory of music (Western classical music) will readily supply you with a list of other notes that will sound nice with your main note. When arranged by pitch starting with the main note, these form a scale.
A fifth is the fifth note of this scale. There are actually 8 notes between the main note and the fifth, but three of them have been determined to sound bad with the main note, so they are not in the scale. The fifth is actually the “best” note to play with your main note (the frequency of its soundwaves is in a nice ratio with the main note), but because we arranged the notes in the scale by pitch and not by how good of a match they are, it remains the fifth rather than the second.
It has a lot to do with the history of how the notation and keyboard instruments evolved hundreds of years ago.
This is gonna sound odd but it’s the simplest way to understand the concept: They hadn’t invented the other notes yet.
A thousand years ago Western Europe did not have the musical system we all take for granted today. They did not live in a world of absolute pitches or 12 equal divisions of the octave where any instrument can play in any key at any time without preparation. The Circle of Fifths didn’t exist because there was no way to close an entire circle so they thought of music as being on a “Gamut” that roughly matched the range of the human voice and included the notes: A B C D E F G and sometimes this weird lower-sounding version of B they called “soft B” that we now call Bb.
These were basically considered the only “real notes” in music at the time, so when keyboards were invented the white keys were used for the A-G regular notes. However, vocalists in the Medieval period and even more so into the Renaissance used a technique called “Musica Ficta” which was a practice of raising or lowering a note during performance to avoid specific dissonant intervals musicians at the time were taught to avoid. So to be able to accompany vocalists the keyboards needed to be able to play the Fictas, which weren’t thought of as “real” notes. So they added smaller keys onto the keyboard to play notes between notes where Fictas usually were. Because there were no Fictas used between E and F or between B and C, they get no black keys.
So when musicians of the time were originally building all this vocab and language used to describe music, the _oct_ave actually only had 8 notes in it. A 5th actually was 5 notes. It was only hundreds of years later that stuff like D# or Gb actually started being thought of as real notes and not Fictas of D and G.
As a slightly related aside: There was a period of time when fretted instruments couldn’t play in groups with keyboard instruments because the fretted instruments were using early forms of equal temperament intonation while keyboards were using a meantone tuning system that made the pitches between the octaves not line up correctly so C# on a harpsichord was literally a different pitch than C# on lute. The history of this stuff is really quite surprising. The 12-tone equal temperament system we’ve all grown up with wasn’t actually in common use outside of fretted instruments until the 19th century.
A fifth interval is the interval between the first note of a scale (usually the major scale) and the fifth note of the scale. 1 and 5 are four numbers apart from each other, which fits your observation that they are four white keys apart on a piano. The 1st and 5th notes are four scale intervals apart.
Latest Answers