How do you choose a key to compose in?

Definitely out of scope for here a MuseScore. We're interested in the technical aspects of using the MuseScore program for creating scores, rather than a fairly subtle aspect of music theory. You would be well-advised to take a simple course in theory to understand this. Here's one that I like: https://www.youtube.com/watch?v=nOnIhOx9uDw&list=PLB585CE43B02669C3&ind…

That said, I'll make a try.

Probably the first consideration in selecting a key is the instruments that will be playing the piece. Guitars can play in any key, but it's a) easiest, and b) has a 'fuller' sound if you compose in G major, C major, or E major (and their relative minors). Likewise violins can certainly play in any key, but the keys of D major, A major, and, to a lesser extent) G major and E major are slightly better than other keys.

Trumpets play in C major, but are tuned so that the instrument they call "C" is actually a "Bb" for most of the rest of the orchestra. Trumpets and about a third of the rest of the orchestra are called "transposing instruments" and this must be handled in composing for those instruments. This wikipedia article https://en.wikipedia.org/wiki/Transposing_instrument briefly describes this situation and how it came to be.

Since you're just starting out composing, I would recommend just going with the best key for your instrument. Sounds like you're composing on piano. So C major and A minor (all white keys) would be one good place to begin. Another possibility would be B major, F# major, Db major, or Gb major, which use mostly black keys. Jazz pianists tend to like these keys.

Still another possibility is to simply ignore key entirely. Simply notate each note played with a sharp or flat as necessary. When you do this, it's likely you will find (as you learn more music theory) that you are actually mostly working in one key or another but you may find that you are not. If it sounds good to you, that's okay.

Good luck!

I'll throw my hat into the ring, along side TheHutch's--

You said that you've composed a half dozen or so piano piece (in another thread, you also expressed interest in piano rags)--do you, in fact, play piano, at least well enough to hammer out your own compositions? When you're composing for a particular instrument, you're not writing sounds in a theoretical vacuum, but for players' fingers (and mouths, for wind players) on their instrument. Some melody lines or passages are more comfortable to play in one key than another.

For instance, the piano: now, most people assume that C major (no sharps or flats) would be the easiest key to play in, and perhaps it is the easiest to read; but on the piano, scales in B major (five sharps) are much easier to finger than C major--just more sharps to keep track of.

So a composer doesn't start out by saying "Today I think I'm going to write a Rag (say) in D major," rather they will come up with a melody, or at least a melodic gesture or figure, and then think--"Okay, now in what key would those notes fit under my fingers best?"

That isn't to say pieces never get transposed (re-written in another key); it's done all the time. Bach took a fugue he had written in F major (one flat) and transposed it into F-sharp major (six sharps) because he needed one in that key to complete his plan for The Well-tempered Clavier. Schubert's publishers told him to transpose his Impromptu in G-flat major (six flats) into G major (one sharp), because they thought that those six flats would be too intimidating to amateur pianists. (But Schubert thought that the melody somehow suggested G-flat; and that's the key it is usually played in today.)

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And then there's the notions that certain keys "suggest" certain moods, at least to the composer. This goes beyond the "Major=happy, minor=sad" concept. For instance D major (two sharps) is "triumphant," and E-flat major (three flats) is "solemn, and full of nobility." G minor (two flats) may be sad, but really desolate music is written in C-sharp minor (four sharps) or E-flat minor (six flats). Why? I don't know exactly, and certainly musicians will argue for hours about what each key really suggests. But I would venture to suggest that, in some sense, when a composer chooses to write a piece in A-flat major (four flats) (for instance), they are in some sense channeling or referencing every other piece in A-flat major that they have ever played or heard--the slow movement of Beethoven's Pathetique Sonata, The Schubert Impromptu in A flat (the one after the one in G-flat), Joplin's "Gladiolus Rag."

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So in the long run, when you sketch out a piece, or a melody, try playing it in a couple of different keys--even if you can only play it poorly--and see which one makes the most sense to you.

Hope this helps . . .

For many professional composers, different keys present different "moods", so to speak. You can test this yourself. Write something for piano in A minor (which is not all white keys, there is the occasional G sharp ). Then transpose it up a third. It will sound a bit different. Then transpose it down a third from the original key. Again, a bit different feel. Then take that same piece and have two other instruments play it. change the tempo. there's all kinds of simple things you can do to it. At some point you may find a key that you prefer for certain instruments.

@mikkel7 wrote: I've composed about five piano solos on MuseScore, but every time, choosing a key signature is a random guess.

The best indication of the key of a composition is the final chord of a section. For instance:

• if the final chord in your piece is an A major then the key is probably A major (three sharps)
• if the final chord in your piece is A minor then the key is probably A minor (no sharps or flats)

Other factors to consider:

a) Does the "final" chord pivot back to the start of the melody? Like a V chord? If so, look for a place where the melody sounds like it has come to rest, to full resolve.

b) Your composition may change keys. If so, use the logic in a) to determine the key of various sections.

c) If you're in a modal key, like A Mixolydian, where the tonal center of the key is A and the likely chord resolution is A major. But since all Gs are natural in A Mixolyzcian some scorists use a D major key signature so they needn't mare every G as natural throughout the score. To be clear, the D major scale played from A to A sounds A Mixolydian.

scorster

Don't compose in a particular key. Whichever instrument you play, just play the music and then write down the notes and then work out the key signature. Maybe record yourself playing if that helps.