Hi...I've been thinking about vibrato recently - what exactly is it for, fundamentally?
Some instruments do it, some don't, and the instruments that do it do it differently. The vibrato most guitarists are familiar with only oscillates the pitch sharp of the nominal note, whereas violins etc will always oscillate the pitch in both directions evenly. Many instruments use tremolo, substituting pitch for amplitude, or other techniques to create similar effects. The basic intention seems to be that of creating a trembling, shimmering note for some sort of emphasis.
..so is that what vibrato is - an aesthetic timbral effect, a simple ornament or something? The one thing that always comes up in its descriptions and definitions is 'expressiveness' or similarity to the human voice. It's true that all instruments capable of vibrato are commonly used as solo instruments, ie those taking the lead role in 'expressing'. It's also interesting to listen to something like Martin Luther King's 'I Have a Dream' speech for the huge amount of expressive vibrato in his voice. So could vibrato/tremolo or anything similar be based on really fundamental vocal tools for emotional emphasis, indicating more emotional conviction in musical metaphor? You can probably tell I've bought into this already.
The other thing I've been wondering is guitar-specific. How much do people use each type of vibrato on general guitar? The obvious one is string bending which only sharpens (mostly)...do many people here often use the other - 'axial'? - that oscillates pitch up and down? The first is obviously associated with electric and the latter with classical. Do you treat them as mutually exclusive? Does the context really matter? Is bending somehow inferior despite its advantages? Any thoughts really..