Enharmonics (or enharmonic equivalents) simply means that a single key can represent several different notes. We actually saw that already when we looked at the 21 unique notes. Below is the same illustration.
We can represent keys as multiple notes by raising or lowering the other keys to form the note in question. So far we have used sharps (#) and flats (b) to achieve that. There are actually (theoretical) situations where we would need to raise or lower a note that is already raised or lowered. The process is actually quite straightforward. A note that is already sharpened that we further sharpen becomes a double sharpened note. And likewise we can create a double flatted note as well. We use a double sharp (x) and a double flat (bb) symbol respectively for that purpose. Sometimes we need to “return” a sharpened or flatted note to its “natural” state so that there is no symbol in front of the note. We “return” a sharpened or flatted note with a natural (♮) symbol. In the illustration below a G key is shown with its enharmonic equivalents both on the keyboard and staff. More on notation in the following lessons.
Notes containing these symbols (#,b,x,bb,♮) can considered alterations since they alter the natural state of notes. (The natural state depends on the harmonic context). When an alteration is not part of the natural scale or mode it is considered as an accidental (note). Alterations and accidentals are essentially nearly identical in context.
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