I have a song that I'm trying to figure out the key center. I'll explain the process and you can tell me if I"m on the right track. I start by analyzing the song using software that finds the chords. (Studio One ) . I know that this is not an exact science even with modern software. It shows the main chords being F-G and D and seventh variations of those including major and minor G's. So that didnt help me since it doesnt seem to fit a progression I would expect from a New Orleans blues, slide song. Next I play the song and hold down various keys and find the one that sounds like it could be the key center. This seemed to work the best as I can just let this tone play for as long as I want, through the main sections, chorus solos... So the D sounds best by far, but I want to be sure I'm right and at this point and I'm not good enough to figure out the progression manually in a timely manner. My question is, is playing the note like I do a acceptable way of finding the key center and how would the three main chords of D,F and G fit into a common progression ? Thanks
When a chord appears in both major and minor forms, consider the possibility that it's IV.
But I have to say, if you need software assistance in finding the chords, you're probably not ready to do much harmonic analysis. Work on detecting what the notes and chords ARE. Hanging a key label on them isn't really that important, is it?
Using that constant tone is certaintly a valid way to determine the key, but I think there are better ways. For starters, using harmonic analysis software, as you have wisely noted, is dodgy at best, impossible at worst. Especially with blues and other non-diatonic progressions, software can't tell the context well enough to put good chord labels on them. But I think the best solution would be to develop a better musical ear so that you could tell "oh, this song is centered on this". It sounds like you're nearly there, so don't despair! And yes, eventually you do need some reference tone to identify "oh, the note the song centers on, that's an E♭ on my (musical instrument)" (I must sound like a broken record, but that isn't necessary if you have perfect pitch).