vibrato

I'm not sure about exercises... I would assume that if you practice it enough the muscle movements will come with time.

As for the squealing distortion, I don't think it's possible with a bass. I'm sure someone will say "You're wrong! I've been doing it for 47 years!", but the way I see it, distortion that will "squeal" with vibrato requires really high output guitar humbuckers, ultra high gain from a Marshall-type amp, and, yes, guitar strings. I just don't think it's a bass sound.

 

for vibrato? just practice, do it a lot, and adventuly you'll grow stronger mussel, and you'll be able to do it.

As for the squeal that you hear from a heavily distorted guitar (found a lot in 80's metal) is a pinch harmonic. On guitar its done when you hit the string with your pick (right hand) and immediatly after you hit it with your pick, "tap" it with your thumb. Its really a technique thats hard to explain in words. It provides an airy sound, and when added with vibrato, it can do some neat effects. I dont think they would come out as well on bass though, but you could attempt them with your nail, and finger.

 

just some pointer-outers...

The reason why high output humbuckers seems to be common with them is because you get heavyer distortion with them. The heavier the distortion, the better harmonics come out, same effect if you crank the presence knob (super high freq.).

 

That's what I meant, it just came out wrong.

 

As for the squealing distortion thing, I can think of two examples: Billy Sheehan and Michael Manring (on "Thonk"). Michael just cranks it into a giant Marhsall rig. Don't know what Billy uses.

 

Billy uses pinch harmonics.

 

The way i look at doing vibrato:

If i were to play a note with my middle finger, think of it as turning a door knob back and forth with your thumb and middle finger. I guess it would be like rolling your finger side to side. But you will become a lot better at it.