Why do double sharps exist

The intervals indicate their place above the root of the chord. In an A major 7th chord , there are four notes. The root, A ; the major third, Cx; the perfect fifth, E ; and the major seventh, which is Gx. A double-sharp is canceled in a couple of different ways. First, it depends if the note should revert back to a regularly sharped note or back to its natural state.

For reverting a double-sharped note back to a single-sharp, simply indicate the change by placing a sharp symbol in front of the notehead. It is also considered correct to indicate a natural sign and a sharp sign in front of the notehead, but it tends to be more difficult to read.

However, if the note needs to be returned back to its completely natural state, a natural sign would be used. Musical terms can have different identities in other common music languages such as Italian, French, and German.

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Like this: Like Loading Next post ». John Morton says : December 10, at am Interesting comment, nicely put. John Morton Reply. Leave a Reply Cancel reply Enter your comment here Fill in your details below or click an icon to log in:. Email required Address never made public. Name required. It might be used by composers to point out certain tonal diatonic or chromatic relationships.

For example, C sharp is "closer" to E double-sharp than to F. That way, composers can make any modulation into E double-sharp and then, by enharmonic equivalency go to the "distant" F. There's even some documented music theory about how to write the chromatic scale correctly based on the current key signature.

The actual reason double accidentals were created was to complete music theory. An example of this would be in augmented and diminished notes. The rules of music theory state that an augmented interval MUST be a raised semitone of the perfect interval:.

Your perfect 5th is an F. When augmenting, the same rules apply. Your perfect 5th is an Ab. To diminish it, the same rules apply. The modern purpose is to use the least amount of accidentals as possible.

When doing this, you should try to make it so you have no written naturals since they are already understood. Only the notes that are not natural should have accidentals. You will find out that this is not always possible with just single accidentals. Below is a blue scale run in the key of C, written 3 different ways. The one at the bottom is the one with the least amount of accidentals.

Using less accidentals makes it less complicated, of course Triple accidentals also exist. Try to guess why ;. In order to create a harmonic minor, the 7th note, in this case F , must be raised. This means that F becomes Fx because in raising, the note preceeding the accidental symbol must remain the same - in other words, you can't have a G and a G in the same scale because all letters are used and only once in every scale out there.

The purpose of double sharps and flats in key signatures is to represent this scale in the way it is written, and avoid constant use of accidentals on a note - as per the example switching between G and G.

The purpose of double sharps and flats within the piece is for presentation; in order to show a section is written from - and can be thought of as - a different scale. For example, in bar 34 of the 1st movement of Beethoven's Moonlight Sonata, double sharps are used to show the broken chord series consists of notes in G harmonic minor, while the piece is written in E major.

Say we have music in a certain minor scale where a particular note is sharp, according to the key signature. In G minor, in the natural minor scale corresponding to the notes of B major, we have an F note: it approaches the G tonic from a tone below. Now what happens if we want G harmonic or melodic minor? We need to sharpen this note to make a leading tone. So F is sharpened again: Fx let the x symbol denote double sharp.

Although this note is enharmonic to G, logically, it is a natural minor scale's sharpened note. It would be notationally awkward because given phrase of music in the same bar could use both the G and the Fx pitches. If the same note letter G is used for both, then there may have to be numerous transitions to G natural and back to G , which might be verbose and hard to read.

There is a bigger problem than merely too many accidentals: namely that the G would be written on the "wrong" staff line. If we use G natural instead of Fx, and then write an ascending G melodic minor scale, we will end up with two consecutive notes on the same line: the G natural and the G.

This would be unnecessarily confusing, visually: a half step looking like a repeated note where you have to decipher some accidentals to see that it is not the case. It would be confusing because the Fx note in the harmonic minor scale in the key of G minor is in fact a sharpened F. It is not a flattened G. We know that the G is not flattened because G is still present in the altered scale it is the root, after all. Flattening a note in a scale means that we remove that note and replace it with one which is one semitone down.

In fact what is going on here that the F has been removed, and was replaced by a G. The notation follows this understanding, and calls it an F double sharp. So this is the purpose of a double sharp and likewise a double flat. It occurs when we want to sharpen or flatten a note in a scale, but that note is already sharpened or flattened by the key signature.

First a few things to keep in mind about major scales other scales don't always follow these rules :. RULE 1 - We must end up with 8 notes.

Which doesn't help us a ton, but it's a start. And for now we can think of it in a few different ways:. So the name of the scale gives us the first and last note! Let's start with D Major - and now we have:. RULE 3 - Every other letter of the musical alphabet must be used exactly one time - in alphabetical order. We're not talking about notes right now - just letters. And each one of them must be in every major and minor scale exactly one time - except for the root - which we've covered - it appears twice.

So now we know a bit more about the D Major Scale:. WARNING: although I know i haven't made a mistake because I'm following the rules - I also know that I'm not finished simply because I know that C Major is the only scale with no sharps or flats - so I know this isn't complete - and that it will end up with at least one sharp or flat - it has to.

But as we go forward - keep in mind that we cannot change any of those letters. We already know they must be there in that order.

So - next rule I used to remember it this way: "a major scale is all whole steps except from the third degree to the fourth degree and the seventh to the eighth which are half steps. Or Mi to Fa and Ti to Do. At his point we have to analyze each 'pair' of notes - in order from left to right - by asking "what the interval is now", what interval do we want it to be - and do we need to change anything or can we move on Here we go:.

Hold on! Did you notice my problem? So like before with the E F G thing, one change will fix both issues: let's raise the C to a C and now we have a major scale:. Anyway - I've shown here a valid reason for needing double sharps and double flats - to follow the rules of major scale construction - the more common use of double sharps and double flats would be to indicate the "job" or "role" of the note in it's specific context.

For example, if I'm playing a song in G major but then start noticing the use of D regularly I can usually safely assume that we've modulated to the relative minor key of Em and the D is being used as a leading tone as in the E Harmonic Minor scale.

A 'raised seventh' in E minor - or an 'augmented fifth' in the context of G major. So - same example - but let's start in B Major and modulate to the relative minor of G m and now we want a raised seventh degree of the G m scale - that's an F double sharp - the leading tone - by 'raising the seventh degree a half step from F to F double sharp. G natural might be easier to deal with - but it wouldn't be a 'raised seventh'. How would you propose we raise the leading tone of a minor if not with the use of a double sharp?

Sometimes notes with sharps in front of them also have to be raised by a semitone and this is where double sharps come in. One benefit of using F x instead of G Natural in a key where G is sharp e. It would be unfortunate to write G Natural, then G again in the same bar. Better to write the F x and leave the subsequent G notes alone, i. From a music theory point of view the double sharps and flats are necessary to preserve the relationship between the notes and the key.

I'll explain by example.