In the last column, we discussed some of the harmonic possibilities for combining guitar and keyboards in an ensemble setting. This month, we'll explore the rhythmic relationship between the two. (If you're not a guitarist or keyboardist, hang in there — we'll get to you in future columns.)

Guitars are great for adding rhythmic punch to a song. Sometimes nothing sounds better than strumming away on guitar chords with a cool rhythm. If the harmonic rhythm (the frequency of chord changes) of a song starts to become stagnant or repetitive, a new guitar or keyboard rhythm over the changes can keep things fresh.

In a lot of rock songs, the rhythmic guitar figure is the signature hook. Most African and South American music, as well as many other regional ethnic styles, contains strict rules of rhythm, so it's a good idea to study a style in depth if you want to sound authentic. However, for songs in just about any style — especially original material — it's a good idea to look at the chord changes from a rhythmic perspective. See if some sections can benefit from a hooky new rhythm on the guitar or keyboards before the arrangement gets too locked-in.

You can approach rhythm comping for guitar and keyboards in an infinite number of ways. Different styles dictate certain approaches, but a few rhythm devices have proven successful over the years. One of the simplest is a two- or three-note chord on the backbeats, voiced in a high register (in the style of the Eagles). This works particularly well with a tight electric-guitar sound when a different instrument (acoustic guitar, piano, organ, synth, and so on) is holding down the harmonic changes. It adds impact to the backbeats without crowding the sonic texture and works well for verses when the chorus or bridge parts contrast with a denser accompaniment.

Another good idea is to create a part for the verse, rhythmically based on an element of the chorus melody. Sometimes you can echo the actual rhythm of the chorus hook, or you can grab the most interesting rhythmic phrase and create a whole new part based on that rhythm. Since verse and chorus melodies usually have contrasting rhythms, the rhythm part in the verse won't double the melody. Also, this device provides the added bonus of foreshadowing the chorus or hook in a way that can make the chorus seem more familiar and memorable when it arrives, without the listener knowing why.

Contrasting rhythmic figures on the guitar and keyboards add a whole new dimension to a passage. Constantly jumping between the different sounds of each instrument on various subdivisions of the beat keeps the texture interesting. This technique can really add to a song's level of excitement when thoughtfully executed. A lot of funk tunes are built on the simple premise that each instrument gets a specific rhythm, and the combination of all the rhythmic elements creates a groove that is stronger than any of the individual rhythms. You can use this device on far more than just funk and dance tunes, though. Practically all song styles — including ballads — benefit from the contrast of subtle rhythmic figures, a big improvement on everyone playing whole notes on each chord change.

Call and response is an effective way to create rhythmic contrast between two guitars or between a guitar and keyboard (see Fig. 1). You can create this effect using several techniques. One way is to echo the exact rhythm of the calling instrument in the answering instrument. In another, more common, form of call and response, the first instrument states a rhythm and the second instrument follows up with a different but complementary rhythm. Think of “I Need You Tonight” (INXS) or “Let's Go Crazy” (Prince).

So how do you come up with a great rhythm part? One of the answers is to put down your guitar or step away from the keyboard and do what your mother used to tell you not to do — bang on the table! A great way to find a cool rhythmic accompaniment figure is to sing the melody of the song and tap, drum, or bang along as you sing, not giving any thought to notes or chord voicings. You'll find it easier to create rhythms that fill in and support the vocal melody if you just concentrate on the rhythm. Once you find a good rhythm, you can easily go back to your axe and carve out a cool part.

Also, arpeggiating chords — whether on guitar or keyboard — does not have the same effect as actually playing blocks of chords in a specific rhythm. Although arpeggiation does provide rhythm, its overriding effect is frequently one of sustain, which is only a step away from holding whole notes. Think of how effective Brazilian music is when the guitarist is playing a bossa nova rhythm with block chords — it's much more interesting and sensual than simply arpeggiating through the chords.

The next time you try out an accompaniment part and find yourself falling into the old arpeggiation habit, come up instead with an actual rhythm part. You don't have to rely on it exclusively for the whole song, but it can add interest to the arrangement by creating additional rhythmic contrast.

Composer and producer Rob Shrock is the keyboardist and music director for Burt Bacharach and has recorded and/or performed with Garth Brooks, Ray Charles, Elvis Costello, Sheryl Crow, Faith Hill, Whitney Houston, Dionne Warwick, Elton John, and a host of others.