I remember seeing EVH do this for the first time and it was like someone planted a grenade between my ears. It just looked so bizarre. So I tried it and, of course, it was incredibly awkward. Fast-forward 15-20 years later I’ve refined the motion relatively well. I’ve even started experimenting with trying it to play actual lines instead of just the usual repeated-note patterns. I won’t say I’m particularly adept at that yet, but I can occasionally peek into another world where it seems like it’s possible.
I think the hardest thing to get used to at first is the string tracking. I’m mostly a UWPS kinda-guy with the base of my thumb generally in contact with the bridge. Eddie’s tremolo technique feels like the complete opposite of my natural mechanic. I first got it to work by sheer experimentation (3-hour sports events on TV are good for this).
However, it always felt like I was making a major switch of “picking modes”. It was so different that to execute the switch, I had to alter my grip, flex the wrist, start fluttering in the air and then “dip” the pick down. I always thought of it like starting an engine on a motor boat out of the water. Not very conducive to smooth playing.
So lately I’ve been trying to keep the same high-speed reflex motion of the wrist without having to do the major grip change and I’ve kinda almost got it working. Again, this is mostly just brute-force experimentation. But over time I find I’m getting the right feel more often than not.
Here’s what my normal grip looks like:
Here’s what it looks like when I morph into “tremolo mode”:
You can see that the base of my thumb is no longer resting on the bridge and that the wrist is flexed just ever-so-slightly outward. For whatever I reason, I’ve always found that cocking the pinky seems to help with this motion. It could be placebo effect, it could be just keeping that knuckle from hitting the strings or something about introducing some tension into the hand to help with the mechanic. I don’t’ really know about that one.
I will say that when it’s working correctly, the hand from the wrist to the fingers feels like one solid, locked-in unit, but not overly tense. The wrist is handling all of the motion, largely through rotational mechanics. When I have it working correctly the motion is really free and easy. I’ve never timed myself but I could probably go several minutes just fluttering away like this (not that anyone would want to hear that).
Hope that helps!