Why “Start slow” fails

An intuitive way to practice a passage would be to start the metronome at a slow speed, perfect the passage, and gradually increase the tempo until you reach the target or goal tempo. For example, if you have a run of 16th notes at 170 bpm, you might start practicing at 50 bpm, nail it, bump up to 60 bpm, nail it, and so on.

Unfortunately, this method rarely works. It is analogous to trying to learn how to run by simply walking faster. You will almost certainly hit a “speed wall”, a tempo at which your movements carefully practiced at lower tempos are no longer viable. There are two reasons why this happens:

  • How you physically play is different at slower tempos and at higher tempos. When playing slowly, your fingers aren’t just moving more slowly:

    • you likely use different amounts of force production

    • you may engage different muscles in fretting and picking

    • you have more time to press and hold strings

    • the physical interaction between the pick and string, fingertip and fretted string, are different 1

  • How your brain processes things is different at slower tempos and at higher tempos. When playing slowly, your mind isn’t just thinking more slowly:

    • you have time to “think about every note”

    • the extra time between events (note changes) allow for different neurological connections to take place

    • the process to play a single note can actually travel through different regions of the brain and access different modalities

Starting slowly and building up speed will almost certainly take you to a speed wall. Speed walls are always a result of using a movement that has limitations. Rather than trying to break through the speed wall by persistent (and misguided) overpractice of the same movement, go around the speed wall by using a completely different movement.

1

During slow playing, the pick may be displacing the string more through a “push and release” action, rather than a fast transfer of momentum at higher speeds, and the skin and flesh at the tip of the fretting finger may have more time to deform to the contour of the string, depending on elasticity. This is a super-gross simplification of the complex dynamic system.