Forget his speed, his vibrato is insane. I’ve tried for years to emulate it with no luck. I use 10s and a normal fretboard. A couple questions:
Do you think that it’s critical to use a scalloped fretboard to get that style of vibrato? It’s so deep.
What gauge strings does he use? If its 10s or higher, I will be dumbfounded. I’m hoping its 9s or 8s and that’s how hes able to get the “deepness” along with the scalloped board. Any insight?
He used 8s and tuned half step down back then but now i think he uses 10s. Scalloped might be helpful but yngwie would sound like that playing anything. Only thing i can think of is Yngwie describing it as „slow and deep”. Its slow type, quite wide and when talking technique he lifts his thumb often. Also high strting action may create more tension when going back - maybe it’s easier to control?
So the first thing is that YJM plays 8 gauge strings (unless he changed?!), and he tunes flat a semitone, so the tension in strings like that is something around 13 pounds, it is shockingly light. That is a huge difference right there vs. what you experience with 10 gauge. The second difference is scalloped frets; what this means, in practice, is that your fingers can’t touch the wood, and this is extremely low friction, because the only resistance is metal on metal (string vs. fret).
I play parts guitars from Warmoth and have scalloped necks, and they’re interesting… however, in exchange for easy bends you pay a huge price, and that is that it is easy to press too hard on chords and make some of their notes go sharp [because the wood doesn’t block you], and the lack of friction against wood also makes certain notes within a chord go sharp as well… not for everybody.
I suggest that you try 8 gauge strings first and see what you think, but don’t do it on a guitar with a whammy bar or you’ll have a lot of annoyance.
Get his fender strings. Or order the same gauges from stringjoy.com.
Tune halfstep down. Set action to 3mm at the 12th for ll strings, if yiu can go heigher do it. Stick with it for three months.
Vibrato, listen to tons of Texas blues and classical violin. It’s a feel thing, you either have it or you have a lot of woodsheddin to get done.
Not specific to Yngwie’s vibrato, but I found this lesson very useful. My main takeaway (or more precisely my reinterpretation of the lesson) was to practice vibrato deliberately as a series of mini-bends where you try to control both the tempo and the pitch range. Doesn’t mean I’m great at it - but I went from unbearable to passable 
Select an example of YJM’s vibrato and slow it down with software and listen to how it sounds. Then play along with it slow. When you nail it, repeat but at a higher speed.
Like it was said before. I think it’s an addition of elements such as the scalloped neck that provide a better grip to the strings, the light string gauge (I’ve tried 8’s and it does make a difference), and add the fact that Yngwie is often detuned one half step. I used to combine all these elements together and it’s easier indeed to imitate Yngwie’s vibrato.
But if you are not used to put a wide vibrato, it’s like every other technique : it needs practice. With practice you can have a wide vibrato even with 10s in standard tuning.
Awesome answers from everyone… A couple other questions. I have no idea how he plays 8s, and tunes a half step down. It seems these two ingredients would lead to a ton of buzzing so I imagine his action must be insanely high? I set up one of my guitar with 8s and I think I could literally bend the B string off of the top of the fretboard.
Other question was how he does the vibrato with his thumb off of the neck. How do you do that? I use the palm of my thumb to push against the back of the neck so that I can vibrato. My palm is essential in any vibrato. How the hell can you vibrato if you take that part off of the neck? Taking my palm off forces me to use these muscles in my forearm that have not been trained at all
That or super jumbo tall frets you need like zero skin contact to fretboard to achieve this kind of fluidity. Super light strings as well.
Folks!
The secret and primary advantage to scolloped neck is HIGH action that feels natural with 8-46 tuned hlf step down. I cannot say this enough. And you won’t hear it in many places either, not sure what that is about.
Sure bending is easier but that’s not my main takeaway from three years on the signature model.
I have no issues bending on a regular neck, but what makes the bending easier is high action.
The high action makes the tone sound huge with all thta gain, with the right amp etc.
the higher the action the more sustain because the vibrating string isn’t deadening itself on the next fret up as fast. It’s a “life hack” that I didn’t realize for years but once you realize it action goes from “how low can this be and be playable” to “how high can this be and be playable.”
Yep it takes work from palm to forearm. Yngwie uses that on longer sustained notes sometimes. But he does opposite while bending so using steady thumb grip as well.
Target the next note in the scale from wherever you are, aim for a triplet feel, particularly use b6 up to maj7 and maj7th up to root and you’ll suddenly feel a lot closer than you did. Regardless of strings/fretboard/tuning etc.
I definitely agree with @BronieV. All the things we said help to get closer to Yngwie’s vibrato but it’s not mandatory. Don’t buy a scalloped neck just to work on your vibrato.
I own an Yngwie strat, a Les Paul, a Kiesel, a Skervesen… and my vibrato does not change with the guitar I play. (it does change a bit when I use heavier gauge in standard tuning tho), I just focus to have a wide and musical vibrato when I’m playing and with practice it becomes more and more natural.
I am not saying that my vibrato is as perfect as Yngwie’s but I just want to repeat that it’s something you work on.
Taking my thumb grip off of the neck makes the vibrato so ugly and erratic. I lose total control of the thing
Try anchoring with the web of your hand between your thumb and pointer finger, maybe. The “blues” hand position with your thumb over/around the neck definitely lends itself to a wider “shake the string around” sort of vibrato than the “classical” thumb-behind-neck position.
Actually, scratch that, I just grabbed my strat to see what I actually do when giving a note some vibrato, and it depends a bit on which finger is engaged (mostly in terms of an inxreased hand angle) but it seems the two contact points are my thumb, around the last joint, on the top/low E side of the neck, and then the “ball” where my pointer finger joins my hand on the bottom/high E side of the neck, and that the vibrato is driven mostly by wrist rotation.
Yngwie’s vibrato isn’t JUST gear, but certainly his preference for light strings tuned down a half step, and a neck that allows you to get a good “grip” on the string rather than on the fretboard below it (scalloped, jumbo frets, whatever), certainly helps… Some of it is definitely technique and practice too, being ale to grip and move the string with little resistance helps get you a wider vibrato, but having the control to do it at a rate that feels musically appropriate, rather than at hummingbird/bumblebee tempos, is also pretty critically important, too.
It might be worth selecting your top 3-5 players for vibrato and seeing (hearing) what they have in common in terms of speed and pitch width and try and emulate. Other than extremes of string gauge, I think its mostly the hands…
Somebody I know says their vibrato is always 6.0Hz. 
He is a great teacher, but note a few things are missing:
He didn’t explain that in non-guitar vibrato the oscillations are around the note, not above it; there are techniques in guitar with pre-bending the string so one can have that forearm vibrato and go around the note on a guitar as well, but I understand that it is rare. Note how easy vibrato is on a fretless instrument, for example!
His first technique (finger vibrato) works very effectively on a scalloped guitar, but I’m sure he is right that it’s not so effective on a regular guitar.
His second technique (forearm vibrato) works very effectively on every guitar.
His third technique won’t work very well on a scalloped guitar as there is no wood to stop everything from going very sharp, but perhaps somebody more intelligent than me can make it happen.
The best bending that I am aware of is this guy, and naturally his vibrato is killer:
no need to increase action at all, scalopped neck does the job, even jumbo frets are enough
Unless you are playing 8-11-14-22-32-46 half step down, high action for one makes it playable and sound better. No questions about it for me or malmsteen 
evidence 