You took a class from Neil Young?
I wondered, too. Looks like Westerly Wood is keeping his own counsel.
Didn't he double-drop D there?
Yes, he did. We saw him tune both E strings down a step.
What does that mean, "play the modal"? Is that a particular scale or what?
In this case, it was shorthand for
mixolydian. The mixolydian mode was popularized in the sixties by Neil Young, Steve Stills, Jerry Garcia, Mike Bloomfield, Al Kooper, Jorma Kaukonen, and others. It was an easy way to break away from pentatonics. So it makes sense that in those days a rocker would just say to play the modal. Mixolydian's psychedelic vibe was all the rage.
The D mixolydian scale is the same notes as the G major scale, but it starts and ends on the D note instead of the G note. The mixolydian scale is the major scale of the tonic chord's fourth note, a.k.a. the
IV or the four chord. G is the fourth note of the D scale, so there you are.
Try it. It's easy. I use it in all the CAGED keys. But be careful. Like any cheap parlor trick, a little goes a long way.
Including the major scale, there are seven natural modes, one for each note in the major scale. They all work the same way as mixolydian but start and end on other notes. Some are prettier than others.
Another common mode: Relative minor tunes often use the same scale as their relative majors. So, for instance, an A-minor scale is the same as a C-major scale and an E-minor scale is the same as a G-major scale. (I say
often because there are more than one minor scale.)