A musical pulse is just like the heartbeat of a person. It’s a constant, regular event that drives the music and helps the musicians maintain synchronicity with respect to the tempo. The pulse is always a function of the tempo. In jazz, the tempo is communicated by the drummer more than any other musician. The bassist, however, is the primary communicator of the pulse. The drummer and bassist must “lock in” together and maintain the same tempo. Most music maintains the same tempo from the beginning to the end of the piece. Longer, complex pieces may change the tempo in different sections or temporarily slow down or speed up in specific sections such as transitions or endings, but generally the tempo stays constant for extended periods of time. In contrast, a bassist can alter the pulse, and the drummer and the other instruments must usually follow along. If they choose to go specifically against the pulse set by the bassist, it introduces tension into the music. This may actually be a desirable thing, and a bassist may set up such a situation purposely. However, for the most part, the pulse is felt consistently throughout the band, just as it is felt in all the arteries of a person’s body.
In Chapter 1, “Use Just Enough Rules,” I described how a bassist may play in two by playing two beats per bar, or in four by playing four beats per bar. This is an example of a musical pulse. The pulse is significant because improvising musicians play to the pulse, not the tempo. When a small jazz group plays a slow ballad, they may occasionally play one or more sections of improvised soloing in a double-time feel. This is often done to introduce some variety into the character of the piece. In double-time feel, the tempo doesn’t change; neither does the rate at which the chords in the song’s harmony are traversed. The musicians create the illusion of doubling the tempo by doubling the pulse and effectively playing in eight. Although the pulse is communicated throughout the band by the bassist, he or she may take direction from others in setting that pulse. You may sometimes hear a saxophonist play a run of notes in the preceding beats to a section as a signal that he or she wants to move into a double-time feel, and the bassist often responds and completes the transition. Alternatively, the bassist may resist the urge for a while, which creates tension and, thus, interest in the music that is resolved when either the bassist moves to playing in the double-time feel or the saxophonist abandons the push to go there.
In a general sense, the pulse is a mechanism a team can use to cope with a tempo that is too fast or too slow for their liking. Instead of synchronizing directly with a tempo, they lock into a pulse that is related to the tempo but may be changed even while the tempo must remain constant. To some degree, external constraints, such as the actions of competitors, dictate the tempo. In companies, senior management may set the tempo of business or a particular project, but the leaders of the teams can set the pulse. The leader of a military squad might double-time the pace of the squad’s march, to get to a certain location to rendezvous with another squad or avoid an encounter with an enemy or with bad weather. The leader of a software development team faced with multiple critical issues might increase the number of team meetings for a two-week period to resolve the problems. At the same time, the leader might increase the number and type of approvals required to deliver changes to the codebase. This would slow down the rate of change to the codebase and minimize the possibility of further destabilization.
Although a pulse is communicated to the greater team and to consumers, experienced contributors don’t pay attention to every pulse. For example, a fast four-beat jazz piece might be perceived as having a rapid pulse that pulsates on every beat. However, many experienced jazz musicians will feel an internal pulse at a quarter of that rate, coinciding with the first beat of every bar. In some cases, when the form of the song defines sections with multiples of 4 bars, such as 8 or 16 bars, a musician will actually think in 4-bar chunks. Similarly, a jazz waltz, like a classical waltz, has a three-beat feel with three beats to a bar. Examples include “Waltz for Debby,” “Alice in Wonderland,” “Jitterbug Waltz,” “Bluesette,” “Someday My Prince Will Come” (popularized in jazz by Miles Davis), and “My Favorite Things” (introduced into the jazz canon by John Coltrane). If the bass walks and plays a note on every beat in a jazz waltz, the pulse might seem rapid, but experienced musicians focus only on the first beat, ignoring the other beats and feeling the pulse in one. When the tempo is fast and the pulse is fast, experienced musicians know that the only way to realistically manage things is to focus less on the details and think more generally. For musicians, that translates to thinking more about the shape and overall story of a solo and less about the specific notes. For a racecar driver, it’s about thinking of the path through a series of turns instead of overly focusing on each specific turn. When we get bogged down in the details, we increase the likelihood of destabilizing the performance.