Hi @bvvarma , what Justin is going for here is a transition that involves a run of 3 bass notes, the last of which is the root note of the 2nd chord. For example, for G to C, you’d have something like G – strum – A – B – C – strum … (I suppose this is 4 bass notes, including the first G).
So, to achieve this you need 2 intervening notes between the root notes of the two chords. You describe something like C - strum - B - A - A - strum (I guess), which may sound fine, but it doesn’t give the same feel as the 3-note descending run. Hence Justin plays B - Bb - A as the run for the C → Am transition.
Thank you so much @jjw, that was a helpful explanation. Had a follow on question if you dont mind. In that example of C to A, i assume “theoretically” we could also play C-Bb-B-A instead of C-B-Bb-A. Is that correct? The former does sound better and is easier with the chord transition, was wondering if there’s some tips or thumb rules to consider when deciding the order.
The run of bass notes would typically go in ascending or descending order. C-B-Bb-A is monotonically descending (i.e. each note goes down from the previous one). C-Bb-B-A is not, since C to Bb is a full tone down, then Bb to B jumps back up a semitone, then B → A is back down a full tone.
Having said that, neither one is “correct” and you should play what you like and what you think sounds good.
Thanks for the lesson! Working the C to G… almost went crazy… trying to get fingers on the next chord after the fill… took a breather… tried again, and again… then BAM! It hit and heard the nice sound!