Slide guitar may have become a stylistic choice over fretted guitar out of necessity by players who didn't have the skills or patience to fret the guitar and found it easy to slide a smooth, rounded object over the strings to achieve a similar effect. But for the greatest blues practitioners, such as Charlie Patton, Sylvester Weaver, Blind Willie Johnson, Son House, and Robert Johnson, slide guitar was an unparalleled mode of expression evocative of the human voice as well as the wail of train whistles — a sound near and dear to country blues guitarists. But whatever its origin, slide guitar is a staple of the acoustic blues guitar sound unlikely to ever be imitated by synthetic, digital means.
The tools that let you slide
Early, rural-dwelling slide players used anything they could find to produce the slide effect. The edge of a pocket knife, a length of pipe, a section of bone from a ham or beef shank, and a medicine bottle were among some of the top "tools" used, but the most popular and effective was a broken bottle neck (which was filed or fired to eliminate the sharp edges). Because the bottle neck was probably the most popular, slide blues guitar is sometimes called bottleneck guitar.
These days, you acquire your slippery weapon of choice by selecting from the pre-packaged slides in the display case at the music store. Metal and glass tubes are the two most common styles (though prepared bottlenecks are available, too) and come in various diameters to fit different-sized fingers.
- Metal slides, especially those made from brass, are heavier (they have more mass), bolder-sounding, and provide better sustain, but they're more difficult to master.
- Glass slides are light and have a rounder, mellower tone.
Many Delta players combined slide technique with fretting, often playing the melodic portions with the slide while their fretting fingers played chordal figures or kept the bass line going. This technique dictated wearing the slide on the fourth finger (the pinky).
Follow these steps to perfect your slide technique:
- Slide an object like a glass or metal tube over a left-hand finger (usually the third or fourth).
- Rest the slide on the strings (not pressed down), directly over the fret wire.
- Change pitch by gliding the slide along the string.
Resting the slide on the strings and playing over the fret (instead of behind it as you do when fretting) takes a little finesse, but eventually, your intonation (the ability to play pitches in tune) and tone (the right pressure that produces rattle-free sustain) will improve.
This process produces a smooth, continuous change in pitch (sometimes called a glissando, or portamento, which is more correct).
At first, your slide playing may sound clangy and rattly as you move the slide around. You can improve your sound by using one of two techniques:
• Dampening (or muting), which involves placing your unused left-hand fingers lightly on the strings behind the slide (toward the nut)
• Employing right-hand palm mutes
Slide guitar is physically easy in one sense — you just drag a slide over the strings and instantly hear the effect, right? Well, it can be difficult to get sliding under control to play in tune and keep the accompanying buzzing and rattling artifacts to a minimum. Slide guitar doesn't require left-hand strength the way normal acoustic guitar playing does, but it does require finesse! Focus on intonation first, rhythm second, and dampening third.