Traditional Irish Music
Accompanists obviously see the point in determining keys and modes, but melody players often don't care to learn. There are advantages though. For instance, if you have trouble starting tunes, knowing the key can give you a place from which to start. Also, it is polite when sessioning to let your accompanists know beforehand what keys you'll be playing in. If you are interested in concocting variations, is can be easier knowing what key you are in and which notes are "safe". Finally, when putting together sets of tunes, you can create a lot of interest via key changes.
However, I'll go ahead and throw this out too: You don't need to know this. As helpful and useful as it is, you don't need it. You may be great with tune starts anyway, someone else can let folks know the upcoming keys, and you can feel your way through the last two without difficulty. I know this because I cannot determine keys or modes. No one ever ventured to teach me how to do it because, being a fiddle player, they didn't see the need. I've attempted to learn on my own, but I tend to be wrong with my judgments. At the same time, I've been doing very well musically because I still developed an ear for the music and a feel of the pulse. So, if you don't have it, and you don't want to learn it, you don't have to. You are by no means a lesser musician.
For those of us that want to add this tool to our toolbox (or for anyone looking to sharpen their tools), a few questions for our fellow TradConnect users. How does one determine keys? Modes? Any tips for doing it more efficiently for those that can?
I can in fact read standard notation, though I'm not sure everyone on Tradconnect can. Furthermore, I have had some formal theory training, though none of it seemed to make sense once I applied it . . . not having proficiency on an instrument that demands the understanding of keys really makes theory a challenge!
Now I am thinking like a guitar player (which I am) rather than a music theoretician (which I also am) and trying to think with the clarity which Jenni has introduced to the thread. If you can identify the tonal center, any capable harmony* player should be able to figure out the major or minor question in the first couple measures. “Major or minor” is another of those “What color is this?” issues. I can recite for you the technical difference between major and minor scales and chords, but this is something even some non-musicians can identify.
In case you can’t or are unsure, you can develop the ability in exactly the same way as learning to identify the tonal center. Let’s use the example of Mason’s Apron again. It is most commonly played in A major. I have heard it played in G major, but the melody has a major tonality. Play or listen to the tune. Now listen to or play a minor melody. Let me suggest the A part of Reel de Beatrice, which is played in A minor – same tonal center, but minor instead of major.
Lather, rinse, repeat. It isn’t even important to choose tunes in the same tonal center as long as you know what you are hearing before you start. I chose these two examples to tag onto Jenni’s advice. Notice that in Mason’s Apron you are playing C#, while Beatrice uses C natural.
*I am using this term because bodhrán players are also rhythm players, but they usually don’t care about the key.