How well can you strum with DT? Or do most players switch to RDT for their strumming technique?
I worked out a DT motion recently which seems to be more consistent for DBX and it has a really effortless powerful attack just because your pick is naturally really flat against the string but this becomes a nuisance when trying to strum as it feels garage spiky.
Anyone have any examples of DT strumming? 
Willing to be wrong, and thereās clearly some elbow, but I think this has a DT component to it.
I can get fooled easily but the way heās turned so hard on the thumb side reminds me of Shawn Lane, and we know that was a DT motion. Itās definitely different than most people look when they strum, whatever this is.
For me, I always strum with RDT and I think thatās pretty common.
I see what you mean!
I should of specified Iām looking for speedy examples, I want it to be capable of these kinda speeds:
Yeah I think most people do, gonna have to take another look at Molly Tuttle, Jake Eddy and David Grier but my suspicion is that they will switch to RDT
I recall the Molly interview she had a clear āmodeā for strumming and it reminded me of the Guthrie/Andy wood āawesome strummingā weāve seen. Soā¦RDT.
And sorry I didnāt know you wanted āfastā. Why does everyone around here care about speed so much??? (kidding).
Iād bet, if the Cornell this is indeed DT that it would have plenty of ceiling because we know DT is very fast and capable.
Anyway, I only posted it because when I saw that video years ago I immediately thought it seemed unusual and DT looking. Best of luck on your search!
RDT is like scribbling back-and-forth with a pencil when oneās pinky side of the hand is on the paper?
I thought that most āfastā strumming was forearm rotation as if shaking water off oneās hand? (Funk guitarists?)
In the above video, isnāt everybody mostly using their elbow? 
I think a bit of forearm rotation is essential in fast strumming (just occurred to me that this might be the reason we donāt see it with DT) but the main driver of the motion is RDT wrist motion. Troy mentions it here:
Definitely some elbow motion as well to help get that boom chuck rhythm but I think the main driver is still wrist
Sorry, more questions. Let N be the width of your strumming, where this would be how many strings you want to cover.
For large N the wrist cannot cover that distance in a comfortable way. I think elbow does that very well. Forearm is rotary so it makes arcs, and this would create too much depth (in the middle of the chord), hence the wrist might be trying to operate during forearm rotation to keep the pick flat (and not on an arc).
I have no idea if this is right but I currently believe it 
Joscho can cover 4 strings almost 5 with mainly wrist and a bit of forearm:
Add in a bit of elbow and then you can get full coverage of the strings
The elbow by itself can cover the distance of all the strings but why is that not more common for guitar strumming? Itās common among Mandolin players for single note tremolo and double stop tremolo but I feel like the tone would be too scratchy and garage spiky on guitar (itās already a little scratchy on Mando). Would be happy to see some examples to the contrary!
For success all of the joints must be going at the same frequency (cycles per second). Let me also assume the pick has to travel flat (to skim the strings for speed).
Then, does this follow?
So I postulate that strumming is elbow, or forearm with wrist to get the right pick path (a line).
This could be totally wrong 
Could you share some examples?
Take the video that @joebegly shared, isnāt that elbow?
Oh, wait, do you think it is rotation about the humerus bone in the upper arm?
Sure there is elbow but you can say the same about violinists and Troy has cited them as textbook dart thrower examples. These are compound motions.
I am only talking about guitar, there are no bows here! 
Lots of joints are definitely turningābut all at the same frequency. Youāre right that it is a compound movement, but the elbow is clearly dominating. I think that wrists are actually necessary in some cases to keep the pick right on top of the string plane, particularly when forearm is used, as forearms make arcs and not lines.
I could be wrong, but to me thatās all forearm and no wrist. To me, his forearm is doing a rotation about its long axis and his wrist is bent at 90 degrees to give him a large lever arm. I can do the rough math for my hands (Iām not sure if heās bigger or smaller than me), but I could probably get 5" away from the string plane and could cover 3" in a mere 33 degrees or soā¦ and isnāt it like EVHās tremolo motion, with the same trick?
Yeah but itās too slow to know if the motion is efficient or not. Iām after a motion that has a high speed limit so when I use it at medium to medium-high speeds it will feel nice and fluent.
At 1:00 in that video, Joscho says āthe arm is doing a bit but itās mostly out of the wristā. My first motion was wrist-forearm, more forearm-y and when I try to use it for strumming the little arc the pick makes isnāt flat enough to be useful for any kind of strumming
EVHās tremolo motion is pure forearm with no wrist component, would be interesting to see if he ever used it for full chords!
EDIT:
Ah yes, Troy explains exactly what Iām saying here at 3:10:
Right, this is why I think it is forearm and wrist: the forearm traverses the distance with an arc, and the wrist keeps the pick on the strings, turning an arc into a line. Is that right? I think soā¦
Look at what he does, not what he says. It is mostly forearm rotation.
Iām very skeptical of what most players say they do, thatās why Iām going off of what Troy says when āthereās a little forearm motion yes, but a big component of gypsy technique is also the hand itself moving back and forthā
So what kind of motion is this? Is this forearm with a flaccid hand? Or is it something else?
Thatās pretty much what he says here:
I have this vague recollection that Troy interviewed him and itās in the backlog of stuff, so perhaps weāll get more concrete details down the road.
Great! I didnāt mention my other question: do you think that he makes his wrist flaccid, too? I am assuming that he does (the whole unit flops around, with just enough tension to hold that pick), but Iām not sure.
Heās pretty fast because he strums 120bpm and always does 16th notes, so he could deliver downstrokes at 240bpm (he does downstrokes on numbers and &, and upstrokes on e and a). And not just that, heās obviously efficient, as he can play a whole show without slowing down or his arm exploding.