Enharmonic Notes and Key Signatures

      What is a Key Signature? What are accidentals? How is it possible for a note like (C) to have more than one name?

      Let's start with the basics. We know that notes (or pitches as some might refer to them), arrange themselves onto the master staff as displayed below.

          But what most beginning instrumentalists and singers don't understand is that there is a lot of space between each note on the staff. For example, between the notes (C) and (D) is the note (C#) right? And between (A) and (B) is (Bb) right? If you play the piano, you know these notes exist because they are represented by the black keys that sit in between the white keys.  

     So what is meant by the Sharp/(#) symbol? A sharp is a type of accidental that means to play the respective note "up" one semitone (or half-step). So if we drew a sharp next to a (C) on the scale, we would now call this note (C Sharp)/(#C). 

      What about the Flat/(b) symbol? A flat is another type of accidental that means the play the respective note "down" one semitone (or half-step). So if we drew a flat next to a (E) on the scale, we would now call this note (E Flat)/(Eb) 

But wait a second, the black keys in the picture have two names! How is that possible, and how do you know which name to call each note if they have more than one? 

           ^The question above brings up a good point. The black keys have more than one name for each note, and which name to call them all depends on what note you're using as a reference point. If a pitch can be represented by different names and different accidentals, then it can be labeled as enharmonic. For example, (D#) is the same as (Eb) because the raising of (D) one semitone or the lowering of (E) one semitone results in the same pitch. Now, how you know which name to call notes depends on the key signature you're in. 

           But without worrying about when to call which notes what, let's talk about how notes can have different names. First of all, it's important to remember that enharmonic names can only be given off the primary tones (my way of saying the "white keys"). So this means you cannot have a note called (F# sharp) or (Eb Flat). These notes *can* be expressed by other notes, but not by "black keys". 

The note (G) can be expressed from the note (F) by an accidental known as a Double Sharp (x). Instead of the note being raised "one" semitone, it is now raised "two" semitones. So (Fx) is another way of saying (G). 

      The note (G) can also be expressed from the note (A) by an accidental known as a Double Flat (bb). Now, instead of the note being lowered "one" semitone, it is lowered "two" semitones. So (Abb) is another way of saying (G). In this way we now have three names for (G). Most all of the pitches on the keyboard have three names except for one, which only has two. (see if you can figure out which one). 

      Anyway, let's now move along and talk about Key Signatures so we can tie in these note names with how they are expressed in different keys. 

Key Signatures are collections of accidentals (sharps and flats) that are found in specific scales (We'll talk about scales in more detail Friday). Key signatures are used in music because they eliminate the need to write out all the individual sharps and flats that unique scales are formed by. Let's analyze a couple examples for absolute clarity on this topic;

The key signature shown to the right is F Major. Note that a flat is drawn on the (B) line on the treble clef. This means that when notes are placed on that clef they are automatically played one semitone below the standard (B). So if a note was drawn on that line, we would call that note (Bb), even though no accidentals are written directly in front of the note, because of the key signature. 

The key signature to the right is Bb Major (We will discuss identifying key signatures at the end of the post). Keep in mind that any notes placed on the (B) line will still be flattened because of the accidental in the key signature, but now we're going to add another line that follows this same method: (E). Now if a note is drawn on either the (B) or (E) line, we know to flatten that note automatically. 

Does this make sense for the flats? I'm going to move on to some key signature that have sharps in them, but if you don't have a firm grasp on this concept, go to this site: Key Signature Help

The Key Signature to the left is G Major. Notice that a sharp has a been drawn on the (F) line in the treble clef. Because this accidental has been written on this line, all notes that will be one the (F) line will be "raised" one semitone (half-step). So if a note was drawn on the (F) line, we would call it (#F). 

The Key Signature to the left is D Major. Notice that an accidental has been placed on the (C) line, in addition to the one on the (F) line. Now, if a note is placed on the (C) line, we know to "raise" it a half-step along with any notes drawn on the (F) line. 

The purpose of these examples was to demonstrate how pitch notation is affected by key signatures. Keeping key signatures in mind, it removes the need to mark accidentals next to each note that is played above or below pitch in different key signatures. This is really setting the stage for the next post on my blog which will be about Scales and Relative Key Signatures, but it's nice to have this information now so we can apply it to the basic principles of Enharmonic Notes. 

Typically, we will define enharmonic notes by the key they are played in. For example, a (F#) will be known as F Sharp in the key of D Major because it's a sharp that's written on the staff. The same goes for (C#). 

Likewise, if we wanted to know whether to call a note (Bb) or (A#), we would look at the key signature. If the key was F major, then it would be called (Bb). 

Now, as you've probably guessed, there are more key signature than just the one's I've used as examples. Here's a picture that shows all of them. 

How do we identify these key signatures? Well, the process is actually a lot easier than it looks. This is because there are some simple tricks within the accidentals that help to identify these signatures. 

For flats: Look at the second to last flat. Identify what line it's on and the key signature is the flattened note on the line (Always major). 

For Sharps: Look at the last sharp in the sequence. Raise that not up an additional half-step and you'll have your major key. 

Notice that these rules apply for every signature except for C Major and F Major (Due to the lack of accidentals or two flats) Sadly, you have to memorize these, but it's a lot better than memorizing all TWELVE.

So tying this back to what we learned earlier, Key signature's allow musicians to write music without having to specify the accidentals of each note. There is one exception to this rule, where a note is written into the score that is indicated as sharp/flat, but is played "as written", meaning it is played without any sharps or flats. This is what the "natural" symbol looks like:
  

The last thing I want to talk about in this post is how notes retain their accidental properties till the end of the measure. As we know, key signatures allow notes to be written with their accidentals "implied" by the line or space they are drawn in. But what if we have a note that is out of the key such as a double flat/sharp or natural? Does that note retain it's new properties for the rest of the piece?

The answer is no. If a key signature indicates that a note is always played flat, then it will always be played this way "unless" specified differently. At the end of the measure that the difference occurred however, the note reverts back to it's form as instructed by the key signature. 

For example, let's pretend this measure to the right is in a key which specifies the note (A) to be flat. Now, we see that after the (C#) the (A) appears again, but this time it's (A) natural. So the difference between (Ab) and (A) natural is one half-step up. At the beginning of the next measure if (A) was to be played again, it would return to it's flattened form.





I'll post a couple examples of this later this week to provide clarity, but if you have any questions that I didn't address in the post feel free to comment below!

Sincerely, ZS