[dfan]

The chord stuff is all perfectly reasonable (in pop music, that is; in a classical piece in the key of C you would have an Em going to an Am way more than to F, for example, and you'd see way more D chords).

I don't buy that Eb/Cm is the third most common key in pop music, though. There's not a whole lot of pop music in minor keys, and Eb is a weird key to play guitar in.

[colanderman]

Eb is a weird key to play guitar in.

Van Halen did it all the time. (Tuning down a 1/2 step is not uncommon among heavier rock/heavy metal bands. I'm not entirely sure why though.)

[wildwood]

That's cool, I hadn't heard of that before. Here's a link with some possible explanations:

http://www.strat-talk.com/forum/sidewinders-bar-grille/24512...

The explanation that E-flat works better with tunings for brass and horns was interesting.

[dfan]

(Tuning down a 1/2 step is not uncommon among heavier rock/heavy metal bands. I'm not entirely sure why though.)

You answered your own question; it sounds heavier.

[Synaesthesia]

Eb in original tuned guitar is very hard. But yeah detuning it 1 semitone is a good trick.

[recursive]

> There's not a whole lot of pop music in minor keys

In my informal survey of the first 6 songs I got on the "pop" channel on pandora, fully a third were in minor keys. (Rumor has it by Adele, and I wanna go by Britney Spears)

[HTryan]

I think one of the primary issues with popular music is that it's often ambiguous whether it's in a major or minor mode, even when the song starts on a minor chord. Classically, one would mark the transition to a minor mode by the existence of an authentic cadence: V/vi -> vi, or by the raised scale degree 5, but neither of those clues exist in either song that you mentioned.

In songs like My Heart Will Go On, it appears that the verse tonicizes I, where as the chorus centers around the relative minor. However does it make sense to say it switches modes every time the section changes? Maybe not

[wildwood]

Keep in mind that, with a capo, any key becomes trivial for a guitar.

[freehunter]

I do hear piano in Eb occasionally, but in my years of playing guitar I can't say I've ever come across it in any song I've played.