A lot simpler to just go to the last bar of the song and find or hear the Root being played, which is going to be the Root of the Key Sig in the majority of cases.

Falling prey to the use of a crutch like this will only serve to keep one at the mercy of the crutch. That won't help your musicianship over the long haul.

Learning to hear the Tonic - by humming it while the song is playing - is very basic stuff, typically should be addressed very early on in music lessons or training. If you somehow sidestepped or missed that experience, it is not impossible at all to work with it and soon train the ears to hear that.

And the results from doing that will pay off in so many ways, this is one of those things that, once you've taken the few short weeks to obtain the ability, it lasts for the rest of your life.

You don't have to be able to name the note, just be able to FIND the Root and hum, sing or whistle it as a song is playing.

If you can do that, then you can go fto your instrument and find the note name.

There WILL be those who will argue about that, unfortunately.


--Mac