Improvisation in bass groove refers to the technique of making up musical syllables and sounds as you go. When jazz singers improvise they do not have any of the syllables pre-planned or thought out in advance. In order to master this skill, bass groove singers must perform improvisation exercises in which they listen to music and create the syllables as they see fit for the tune of the music. Improvisation exercises are designed to familiarize the singer with syllables and sounds, and teach him how to think on his feet in the middle of a song.
Jazz vocalists must learn how to articulate the sounds of syllables in a song. Articulation has to do with how the sounds are formed, and is relative to teeth, tongue and lip placement for the singer. As such, a bass groove technique involves practicing the articulation of various sounds and the combination of syllables to create new sounds, such as bo-bee-dee and dee-bop-bop. Stringing the syllables along in two, three and four beats -- or more -- creates a scat.
Jazz vocalists rely on vocal inflection to produce sounds in different notes and octaves. The inflection of the voice pertains to how high or low it goes, as well as the pitches and notes that the voice is capable of reaching. For bass groove techniques, practice singing syllables with a variance of inflection. That is, sing your syllables from a B-flat to a high C, and then down to an A-minor. This type of exercise prepares your vocal chords for being able to scat more musically, and keep the sounds of the syllables smoother as you string them together.
In the vocalist and musical industry, the vibrato is a singing technique in which the sound produced from the vocal chords is pulsed or vibrated, with control, in order to create a fluctuating sound. Vibrato is often incorporated into the ends of syllables in bass groove singing, but takes a lot of practice to achieve. The ability to create vibrato has to do with the strength of the vocal chords and the ability to control the muscles in the diaphragm and throat. As you sing the syllables for a scat or jazz ensemble, practice the vibrato technique.