They may be used to add simple vibrato or tremolo to a melody, or for more complex applications such as triggering gate envelopes, or controlling the rate of arpeggiation.
The keyboard usually covered three octaves, and had a number of switches to alter the tone of the sound produced, add vibrato, and provide other effects.
For instance, in the third movement there is a long cello solo, and for the accompanying static chord he wanted the tone starting without vibrato, then adding vibrato.
Ms. Spears's voice isn't strong enough to radiate sincerity, and as she dutifully adds vibrato in one spot or scratchiness in another, she sounds only more manipulated.
This could add vibrato to the notes when aftertouch pressure was applied to the keyboard.
This technique is used both to play notes not available at a node as well as to add vibrato to any note.
Sawists can add vibrato by shaking one of their legs or by wobbling the hand that holds the tip of the blade.
When she wants to bring emotion to a song, she slides notes, adds vibrato and lets her voice break according to Broadway conventions.
The howling continued and grew as more wolf voices added dissonant notes and vibrato.
Neither a piano nor a harpsichord lets a player add vibrato to a note, as a clavichord can.