Guidelines for finding tonality/key of a song

Question

I am trying to determinate in which key a song was written. I am not musician nor music student. I knew some clues for finding the key but I am having trouble with a specific song because the criteria that I have used previously contradict each others.

Here are the links to the song "Man I feel like a woman" and the corresponding chords (I disagree in the existence of Cm but it is inconsecuent).

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My efforts:

• In the verse the chords are: Bb and Eb. It starts with Bb and uses it most of time: This leads me to perceive Bb as rest and suggest a progression I(Bb) IV(Eb).
• The bridge includes Ab and Bb, which clearly suggests that it is really I(Eb) IV(Ab) V(Bb) as those grades are very common. Also, think "I feel" Ab as IV (but I am very doubtful about that).
• The chorus uses: F, Dm, Bb and Gm. As neither F major chord nor Dm belong to the Eb major key the latter is not the key of the song. Those chords fit well in the key of Bb, but not the Ab major of the verse.

I think that a way of interpret this is as a tonality change from Eb major to Bb major. Is that reasonable? If not, which mistakes I made and how to approach the problem?

Edit: Also F works for the chords of the chorus. Although they share those chords they differ in the use of E and Eb. I found that E sounds better with the music, so maybe it changes from Eb major to F major keys. I've seen many times 1 tone change (in tonality) so maybe it is more reasonable.

Answer 1

The basic chords...

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verse

Bb Eb
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bridge

Ab Cm
Bb
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chorus

F
Dm Bb F
Dm Bb Gm
----------

...look for pairs of chords whose roots are a fifth apart...

Eb Bb and Bb F

...such pairs are possible tonic and dominant chords. If you can make a case that you have real dominant to tonic movements, those tonics could be your keys.

You might say the verse and bridge are in Eb major and the chorus is in Bb major. But, the music might not really sound like it is in those keys. Certainly the key signatures match up the with chords of those sections. But simply matching diatonic chords to a convenient key signature doesn't mean the music is really in a key.

We would expect to see movement of Bb to Eb for Eb major, and F to Bb for Bb major. In Roman numerals we expect to see V to I to make a key clear. We don't really see those movements so in terms of guidelines we could try moving on to another description of the tonality.

If Bb seems like the center of the verse/bridge, you could say it is in sort of Bb major with a Mixolydian flavor from the Ab major chord.

If F feels like the center of the chorus, you could say it is F but using the dominant C major chord, it uses the subdominant Bb.

Both of those points...

• using the bVII chord for a Mixolydian flavor
• using the subdominant in lieu of the dominant

...are very typical things to do in pop/rock style.

Another thing it does is use pairs of relative major/minor chords like F & Dm and Bb & Gm ...you might add Ab & Cm too, but I like to pay special attention to relative major/minor pairs when it involves a tonic chord. In this case Ab and Cm aren't really vying as the tonal center, they are really secondary harmonies. In the chorus F and Bb are the tonal pillars. Pairing the relative minors with them is a kind of elaboration of main tonal chord. At least that's how I think about it.

If you are a purist, you would say this song isn't really in a major key.