|from Hal Leonard's Guitar Method Guitar Techniques|
One of the many cool yet underappreciated features of an electric guitar is the ability to control volume after the string attack. For example, if you attack the string with the volume off and subsequently turn it up, you’ve just performed a volume swell. This technique produces an almost violin-like tonal quality. There are two ways to perform volume swells: with the guitar’s volume knob or with a volume pedal.
Volume knob manipulation is more common because you don’t need to purchase an additional piece of equipment, but it also requires a bit more dexterity when performing fast lines. Guitars such as the Fender Strat have their volume knobs placed very near the bridge pickup, which allows the player to curl his or her pinky finger around the knob while playing to facilitate rapidly played passages.
Rather than picking the notes, you may wish to use hammer-ons, which will enable you to focus your pick hand entirely on the volume knob.
Neoclassical rock guitar virtuoso Yngwie Malmsteen is one master of this deft technique. And when he combines volume swells with classically inspired melody lines, the technique is that much more effective. Give this neoclassical notefest a whirl using the volume knob to produce the swells. Remember, attack the note with the volume rolled off, quickly turn the volume knob on with your pinky finger, and then roll it off again before striking the next note. To make this line extra-special, add an echo delay set to repeat between notes.
If you have a volume pedal among your effects, it may provide a simpler alternative to volume knob manipulation. Try the above example again, this time using a volume pedal. Perhaps the most common use for volume swells is to create ambient, sonic textures. This is especially effective when used with chords.
For the next example, you can use either the volume knob or a pedal. Strum the chord with the volume off, then turn the volume on at a moderate pace. Remember to turn the volume off again before switching chords.
Hit page 2 to learn the slap and pop technique used by funk and country guitarists...