NOW YOU SEE IT, NOW YOU DON’T. Great magicians have a way of making the impossible seem real. At the turn of the last century, Harry Houdini toured the world, challenging local authorities to strip-search him, bind him in shackles and handcuffs, and lock him in their most secure jail cell. He would inevitably escape, much to the thrill of his adoring fans and the dismay of the police.

Harry Blackstone Sr. was famous for sawing his beautiful female assistant in half with an electrical circular saw, somehow without damaging her lovely torso, while Uri Geller became known for his supposed psychic ability to read minds and bend spoons. (I could never understand why it’s so impressive to bend perfectly good spoons. If Geller were truly a mystic, he would take a cheap knock-off Jazz Bass, turn it into a Sadowsky, and start slapping like Marcus Miller. Now, that would be magical.) Street hustlers are fond of Three Card Monty and the Shell Game—simple, crowd pleasing scams that are completely controlled by the hucksters and their shills.

NOW YOU HEAR IT, NOW YOU DON’T.

What do magicians, hucksters, and hustlers have in common with bass players? When a good bassist hits a groove, the feeling is magical—the sound and feeling become more than the notes and rhythms. With a little extra sleight of hand, a bassist can turn a groove on its side. This month, let’s explore some of these rhythmic illusions.

Playing across the bar line can give a bass line an extraordinary, supernatural feeling. In the simplest form, this means playing a repeated three-note figure in 4/4 time, or a repeated four-note figure in 3/4 time. By playing rhythmic groupings against the underlying meter, an illusion is created. The bass line seems to magically float at a different pace than the original pulse.

Example 1 shows a simple three-note grouping, repeated for four bars of 4/4. The note A, which is the root of the chord, is played every three beats, giving a feeling of rolling over the bar line. Try the line slowly at first while keeping steady time. Tap your foot either on every downbeat (beat one of each bar), or on beats one and three. Once the line and rhythmic feeling are in your ear, try this variation: Play four bars of a walking bass line in 4/4, then play Ex. 1 for four bars. Repeat the eight-bar exercise until you can comfortably switch back and forth between the four feeling and the three feeling. Be sure to stay in 4/4, even when you play the three-note groups.

Play Ex. 2 with a driving rock feel. This line is built with groups of three beats, too, even though the first beat is divided into two eighth-notes. You can expand the exercise by alternately improvising a bass line for four bars, and playing the written line for four bars.

Example 3 is walking bass line over an F7 chord; try using this on the first four bars of a blues in F. Once you are comfortable adding the groups of three notes, you can use a similar three-beat, repeated figure anywhere in the blues. Commercial gig warning: You will make novice dancers lose their grip on reality if you do this too often. If you notice your bandleader giving you the stink-eye, just ignore him while you slip back into a polite, four-beat pattern. If your drummer gets that slightly maniacal grin and starts to follow you on your magical rhythmic journey, make sure you know where one is, otherwise things could get messy.

Three-against-four is a common way to imply the illusion of a different time feeling, but there are many other possibilities. Example 4 uses four-against-three—a group of four notes in 3/4 time. Start by playing a medium, swinging, 3/4 waltz vamp over a Dm7 chord. Now play Ex. 4, and feel the time shift. Four bars of 3/4 contain 12 beats, which can be divided nicely into three groups of four.

Other variations of the across-the-barline concept include:

• Groups of three eighth-notes in 4/4 time
• Groups of three quarter-notes in 4/4 time
• Groups of three half-notes in 4/4 time
• Groups of five eighth-notes in 4/4 time
• Groups of five quarter-notes in 4/4 time
• Groups of two quarter-notes in 3/4 time
• Groups of four quarter-notes in 3/4 time
• Groups of four eighth-notes in 3/4 time
• Groups of five quarter-notes in 3/4 time
• Groups of five eighth-notes in 3/4 time

You can expand your groove vocabulary by experimenting with repeated rhythmic patterns outside the basic meter of a song. Create your own rhythmic patterns across the bar line, and feel the magic.