When learning how to sight-sing, one of the first skills you need to master is the ability to find “Do” (as in do re mi fa sol la ti do) no matter what the key signature. “Do” is the solfege syllable used to designate the first scale degree of a major scale. It can also be called tonic. “Do” is the name of the key that you are singing in, so when you find “do”, you also name the key. In other words, if “do” is “C”, then you are in the key of C.
What is a key signature?
The first question you might have is “What is a key signature?” In music, a key signature is a collection of sharps and/or flats located between the clef and the time signature on the five-line staff.
Sharps look like pound signs (#) on your telephone (sharps are pictured in the illustration above).
Flats resemble the lower case “b”.
Finding Do in Sharp Keys
When the key signature is made up of sharps, you can find “do” by locating the sharp furthest to the right. From that sharp, go up to the next line or space – that next line or space will be the name of “do” as well as the name of the key.
In the illustration above, the sharp furthest to the right is on the “C” space (so it is C#). The line directly above that space is “D”, so “do” is “D”, and we are in the key of “D”. This works even if there is only one sharp – that sharp is then the furthest to the right.
Finding Do in Flat Keys
When the key signature is made up of flats, we use a different approach. You still locate the flat furthest to the right. Then, you go back one flat to the left to name the key. The illustration above shows how this works – the flat furthest to the right is on Db, the one immediately to its left is Ab, so we are in the key of Ab. Another way to think of this is to look for the second to the last flat.
Wait, what if there is only one flat?
This does not work, obviously, if there is only one flat. In this case, the key is F. This is something you should memorize.
You can also think of the flat furthest to the right as the syllable “fa”. If you think this way, then you can always just count down from that flat to find “do”.
What if there are no sharps or flats where the key signature should be?
If there are no sharps or flats, you are in the key of C, and “do” is C.