For years, Bob Weir was more than Jerry Garcia’s rhythm man in the Grateful Dead—he was an integral part of determining where the jam kings took their long, strange trips. Weir continues to move forward in his role as one of the guitar world’s great rhythmic improvisers in Furthur.

Can you explain how you use voice leading when shifting chords?
Of course I listen to the leading tone, but I also listen for the sum sound of the chord. Somewhere in the middle there is a ground zero—I’m not talking about the root note— and it’s especially true if you have more than three notes. I try to recognize that and follow its motion from chord to chord. It’s sort of like the Om in the middle of the chord, but it’s nothing mystical or new to me. I’ve heard chords that way since I was a kid. I’ve only recently become aware that is in fact what I’ve been doing.

How did you come to this realization?
Well, it’s highly intuitive, but I recognize it when I’m writing songs. After I’ve chosen two chords, I almost know by triangulation where to go with the third chord. Try it. Play two chords, and see where they want to take you.

How do you determine what chords or pieces of chords to play while listening to a lead player improvise?
I try to select chord voicings that grace the lead player’s pivotal note. For example, if we’re in the key of A, and the lead player is working around the 5th, then I will not. I’ll work around, say, the 3rd, and then move that up to perhaps the 4th or 6th. I sort of circle the lead player’s pivotal note. I listen for the lead player’s motion, and if the pivotal note moves, then I find another complementary note to pivot around.

Do you have any methods for building interesting jams?
When we jam, there is often more than one lead—it’s sort of like rock and roll Dixieland. Everybody plays support, and then steps out here or there. I will often start working a groove with a particular chord progression, although it can be a melodic progression of single notes as well. Once the progression is established, I’ll drop the first chord or note. Then I’ll start moving the progression forward from the second chord or note while adding a new place to go at the end. I’ll repeat that process working from the third figure, and so on. That’s a fairly mechanical way of doing things, but it works to provide motion.

What misstep do you see players in improvisational groups make most often?
Well, it’s nice to have at least a somewhat clear notion about what you’re up to and where you’re headed. It becomes more intuitive the longer you work together as a group. A decent night is full of surprises. Players come up with new twists and turns that are based off of a standard approach to how you progress through the chords, melodies, and dynamics on a given tune. If you don’t know where you’re heading, you can wind up sitting in a groove too long. You’re able to throw more colors at the crowd if you can be concise and keep moving.

How do you build a given passage to its highest possible peak, and then understand when it’s time to move on?
That’s something that you develop as you learn to play the band, and the band learns to play you. That said, I’ll use the head of my guitar like a baton to lead the band. I simply raise or drop it to motion them up or down dynamically. Of course, there are more standard ways of doing things. You can set the solo for 32 or 64 bars, or whatever it needs to be. That’s worked since the dawn of improvisational music.

Is there an art to knowing when not to build— just play at a steady level?
We don’t do that much. Working away at a steady dynamic comes across as noodling to me more often than not. I don’t want to do that, and it tries my patience when I hear it. The guys I play with moved past doing that long ago.

So playing with dynamics is the key to not noodling?
Dynamics are inseparable from rhythmic, chordal, and melodic development. They are the compass points of the world you are trying to create.

Interesting. I only brought it up because there are plenty of songs on the radio with guitar solos that stay at a relatively steady dynamic level. You’re not interested in that at all?
Nah. Even a guitar solo for a radio single should incorporate dynamics. A statement made without dynamics is incomplete.