The core question here will be, as per title, how long do you have to spend in key [x], as measured in time or chords, before it feels like a key change, rather than a bunch of non-diatonic chords?
But the song I’m going to use as a prop has another property that I want to ask about first, which will be spoiled if I send you right to the candidate key change… so first listen *only* to the first 12 seconds (until the melody starts) (all the links and videos I’m including will start and stop at the right times). All the chords you’ll here are [B][E], or really [Bsus4][E/B].
Is this in B (I→IV, I→IV…), or is this in E (V→I, V→I…)? Is it self-evident with no melody, just by the way it’s played? Does the sus4 matter a little?
OK, now think about that for a bit… are you back?Continue reading to find out whether it’s B or E, and to find out how many chords do make a key change… →