Start this 2nd clip from around 5:50 in.
Later in the post I'll explain exactly what makes it possible to do this safely, including close-up video demonstrations of the basic actions (nb. it requires a lot more than gravity/relaxation alone). If you want to try the practical part right away, then feel free to skip to the videos and instructions right at the end. To start with, I'm going to be be looking at playing from close contact, however. I have a strong proof that gravity can only generate a very moderate dynamic here (without additional acceleration through correct movements). Don't worry though, I'll keep the scientific explanations as simple and accessible as possible. The main thing I want to do is to convey quite how modest the result is when hoping to use gravity without any run up.
You may be a little shocked by this, but releasing even a literal tonne of mass on to the keys could not produce a significantly loud sound when released from direct contact!
The touch-weight fallacy
Before going back to that, I want to start by debunking an incredibly prevalent piece of misinformation about the level of force required to play the piano. Somewhere along the line it became trendy for people to start claiming that to play you require the equivalent of merely 40-60g or so of force. Their heart may be in the right place (and it's certainly true that efficient technique uses far less brute force than some people think is needed). But to imagine you can get results by literally stripping down to 50g worth of pressure is nevertheless a complete fantasy built on incorrect application of facts. As you'll see later, the most effortless results are earned by addressing the keys with the right style of positive input, not by simply choosing to put little in and then expecting a free lunch.
Anyway, what the static touch-weight of a piano key tells us is the amount of mass required to depress a key with quite so little energy or acceleration that it doesn't even produce a sound! Assuming you are playing anything other than John Cage's 4:33, you're going to need at least some of the hammers to succeed in arriving at the strings and often with substantial energy. A piano key may start with only a small resistance, but the moment you start trying to produce even moderate levels of tone, it pushes right back at you. By the time you are playing even fairly loudly there will be overwhelmingly more resistance to overcome. The relevant term is dynamic touch-weight. This is the term for the true force required to produce a certain level of tone. There's not a lot of clear information out there on this, although I recently got into a discussion about this on a Facebook forum that inspired me to start investigating more deeply.
Dead weight and volume
After this issue came up, another poster told me that he took a mass of around 680g and released it on a piano key (from direct contact). By his assessment, this mass (with far more than 10 times as much pressure as some people have tried to tell us is sufficient for the whole of pianism) produced no more than a rather moderate mezzo forte dynamic. Although I was already aware that dynamic touch-weight requires far greater pressures than the static figure, I have to say that this greatly surprised me. In fact, I cautiously took out a 2.5kg mass and tried releasing it on my own piano. Admittedly my experiment was somewhat compromised compared to a true scientific standard, owing to the difficulty of releasing the mass abruptly. However, not a single attempt was able to reach a notable dynamic. After seeing this, I was happy enough to trust his word of only reaching mf with 680g (particularly as he had been arguing that piano playing takes very *little* active force- a case which certainly wasn't helped by this result).
To give more context, if I "weigh" my arm on a kitchen scales, I exert a pressure equivalent to between 600-800g of mass. My arm itself has far more mass, of course, and this is admittedly based on too many subjective factors to be exact (hence the deliberately broad range). However, what I'm saying is that when I simulate the kind of pressure I'd expect to apply (while "resting" my arm via a held note at a piano, whilst maintaining an aligned wrist) it will not go past 800g without a notably obvious muscular pressure. I would have to start pushing significantly more than it takes to merely keep my arm out in front of me. By the way, I'm no Charles Atlas, but I'm not afraid to curl a 15kg dumbbell either. My arms are far from abnormally light. It might well have been assumed that 2.5kg would be substantially less pressure than a resting hand would apply, due to the arm's weight but, no. Check it yourself on a weighing scales if you don't trust me.
For the final experiment, I tried releasing my arm's weight down on the keys, to see if anything would be different. This is very difficult to assess objectively, so I channelled it through the end of a pencil. One reason so many people think gravity does so much for them is because of the pianistic instincts they have developed- in the actions of their hand and upper arm. By resting into an inert pencil it's a lot easier to eliminate any active contribution from the fingers. It is always going to be a little subjective and imprecise still (and this certainly can't be counted as laboratory conditions for actual scientific data). However, I'm confident that I have good ability to distinguish between notable pushing vs releasing my arm. When my arm is releasing you'll see the wrist sink downwards with gravity. If that doesn't happen when you try this, you are pushing forwards significantly (rather than solely dropping the arm's weight into the movement of each key). This is likely to become a big contributor to the volume being produced. You'll see at once how much more sound I can comfortably achieve when I wilfully deliver a more precise muscular acceleration to the key (even through the neutral pencil). If you want to see what genuine gravity alone does from contact, you must fight your every instinct to deliberately send energy into the key and simply release everything and observe. Notice how relatively weak and thin the sound is (even via a cheap camera phone which adds a lot of gain). At the end I also tried to go a little quicker. Bobbling on to every key with the arm alone is cumbersome and difficult. It's also hard to fully let go when you also have to get somewhere else in a hurry (thus the even weaker sound than before). When trying to genuinely pass on gravity alone there's no chance of speed or finesse. It would at least require some more active arm pressure but above all it needs living fingers that can move. One separate arm descent per note (plus a necessary reset to go again) is not something that is conducive to either speed or control.
Proof that gravity is ALWAYS this limited (from from direct contact)
I'd already been considering the theory as to why dropping a mass from contact might well max out at a certain dynamic level, although what nevertheless caused real surprise is quite how low that dynamic limit proved to be. I'd anticipated something of at least forte or more, not a moderate mezzo forte. What I'd seen in practise now inspired me to dig a little deeper, to see if I could make a more solid proof that there is indeed a very low dynamic limit. As luck would have it, I could indeed. The thing about gravity is that it needs time and distance to create a large speed. Drop from a big height and you'll land on the keys with abundant kinetic energy already in play. When you start from a stationary contact, however, you have no starting energy at all. The only energy that you can pass on via gravity is that which is released over the 1 cm or so through which a piano key descends. The counter-intuitive part is that even a vast mass cannot generate much acceleration in so little time. Indeed, no free falling mass can ever accelerate at more than the basic gravitational rate (of 9.8 m/s squared).
Consider the famous experiment in which both a feather and a cannonball fall at the same speed (as long they are in a vacuum, to eliminate air resistance). They both equally represent the absolute upper limit at which any free falling object can accelerate. Strictly speaking a mass that starts in direct contact with a piano key cannot quite reach even that level of acceleration, because the key itself is putting up some resistance. Here the amount of mass really does matter. Below the touch-weight you can't move the key at all. Add barely enough and the key will first go down very slowly. However, as the mass gets larger the resistance becomes ever more inconsequential and key will start to move faster and faster.
HOWEVER, what we have to remember is that it edges towards an upper ceiling of possibility. Beyond a certain amount of mass the key will be moving at something fairly close to the rate of a free gravity drop. After this point you just continue to get slightly closer to the limit. No amount of mass may ever surpass this rate. To find the limit we can do a calculation of the results here. With even a huge mass released on the key, you would be looking at something marginally slower than a 1cm free fall (the basic distance by which a key descends). It would therefore take at least 0.045 seconds for the key to descend and reach a maximum speed of just 0.44 metres per second. To give some context, James Ching did an experiment in which he found pianists to take between a 10th and a 150th of a second to depress a key. This is very much in the slower (and therefore quieter) range of the available spectrum here. Even allowing for a degree of possible imprecision in these figures, both the observed practical reality and the mechanical theory are both clearly showing us that gravity is objectively incapable of offering more than very moderate dynamics, via close contact.
Briefly returning to forces, this graph (reproduced from "Pianos Inside Out" by Mario Igrec) suggests that you'd need around twice as much energy and more to produce FF or FFF, compared to mf. Clearly the weight of the arm is woefully insufficient, when we play from close quarters.
The missing ingredients
Somehow, gravity has become so widely viewed as the ultimate "freebie" that a lot of people wouldn't even stop to consider what else must be present in the mix here. They'll just assume my working must have gone wrong. I assure you it's air-tight, however. To see what's genuinely missing, imagine now if you dropped a bullet alongside your falling cannon ball. Again the speeds would be identical in a vacuum. However, if you fired it downwards from a gun, you would easily beat any object that merely falls. Gravity cannot begin to compete with the level of acceleration achieved by active propulsion. The idea of using only gravity to make a big sound via contact is pure fantasy. We should not be fooled into treating it as a good source of acceleration from a stationary start. Indeed, you don't even need to pack a weapon in order to beat gravity. Drop a ball from shoulder height and you should still be able to quickly swoop down and catch it. Yes, movement via muscular contractions can easily beat gravity for acceleration. Muscular pressures get a bad rap because doing it wrong leaves them tired, sore and overworked. However, the reality is that you cannot even get a basic result without instead learning to do them well. Pretending they have no role (or that you can get by on a mere 40g force) is not going to give you a thing (unless you're unbelievably lucky with instincts).
"Timing"- the effective delivery of movement from a run-up
At this point, I'm now going to show you the biggest secrets to making a gravity drop land effectively. The problem with colliding with a key whilst already in motion is that you tend to knock the hammer away more abruptly. That's because you get slightly slowed down when first meeting resistance. Experiments by Ortmann proved that a sharp blow from a distance can knock the hammer out of contact with the key before you reach the escapement level (where the hammer usually separates from the key, during a smoothly paced acceleration). It's a high force but tiny contact time. The full energy applied depends on both aspects, not on a single size of force. This means a severely forceful (yet brief) hit may reasonably transmit less overall energy than a longer one with lower force.
To clarify this distinction, imagine hitting a supermarket trolley as hard as you can with a baseball bat, vs resting your hands against it before accelerating it more smoothly away. A longer push can easily generate more acceleration and without the painful impact associated with a short but vast contact force. On this basis, some even believe that you can generate more sound by pacing an acceleration from direct contact with the keys, rather than dropping the arm in from a height. It's highly counter-intuitive but you can see and hear quite how much sound Nyiregyhazi could accomplish this way.
Start the clip at around 3:40 (where the sound is already huge, but he's really just getting started).
Interestingly, top snooker coach Barry Stark has published a video in which he works around the same basic concepts that I've applied to pacing the depression of piano keys.
As he says, it's not a conclusive scientific proof yet, but there are encouraging signs that (at 35000 frames per second) the well "timed" shots indeed seem to have a slightly longer collision with the cueball. The explanation for this would be down to pacing of acceleration. Top pros don't stab at the ball and stop, they are always trained to aim the acceleration specifically through the moment of contact. This is why a seemingly gentle stroke can generate huge power. Whether at the piano or playing snooker, it's not good enough to just reach a high speed and let the ball/key get in the way of that. You should pace it so acceleration is directed most specifically between the point of contact and release. This was why gravity was so poor at making sound from direct contact too. It cannot focus a special degree of extra acceleration into that small window of opportunity. Weight just stays as a lifeless constant, that offers no extra zip when it matters.
Accelerating the finger/cue tip through the contact means it can be less significantly repelled by the force of collision and thus could spends a little longer passing on energy before detachment. Even microseconds can make a significant change when we're already looking at a very brief contact. The longer you can make the contact via timed acceleration, the less absolute speed/force is required. The degree to which difference would show up would be very hard to prove, but it's certainly a theory that is consistent with Newtonian mechanics.
Applying the active acceleration of good snooker technique to chords/octaves at the piano
In snooker, all shots are made by collisions rather than "pushed" from stationary contact. However, at the piano we can work both ways. The real trick to landing arm drops lies in knowing how to push the knuckles AWAY from the piano key (rather than collapse them into it). This ensures the the peak acceleration goes to the fingertips and thus the key and that any excess energy can rebound safely rather than cause impact. When the knuckles are pushed away, the contact between finger and key is gaining extra distance away from every other moving part of the hand/arm- proving that it has the largest acceleration found in any part. When this is right at the business end, you can impart much more energy before loss of contact. Imagine a snooker cue where the tip actively shoots outward on a spring in the instant of contact. This is what our hands can do at the piano, to stay with the resistance of the hammer for as long as possible. They are not as rigid as a snooker cue, so if you fail to employ any of their activity at all, they will tend to give way (even when trying to be very stiff). Sending at least some extra motion from finger to key gives us an extra advantage that snooker players cannot access. The second issue is that a slight forward push of the arm can give some further impulse again.
In this video I show three styles of movement, only the last of which is genuinely effective- please don't misunderstand that I'm recommending the first two ways to play! This is from contact first, before we proceed to the big arm drop.
The first group is mostly just collapsing the wrist with both gravity and a little extra active swinging down. This is not an effective way to pass energy and delivers little of the total energy to the fingertips. However, you should practise this a little, both to recognise the flabby sense of contact with the resistance (which prevents any good sense of acceleration through to the hammer's release) and to learn to let your wrist be capable of this type of looseness. The second group is based on simply creating a fixed structure and shoving the whole arm straight down on it. This isn't chiefly about releasing weight, but a very active pressing down of arm mass. The sound is loud alright, but this is a very awkward and unsafe way to play. The descent of the arm (via strong thrust) carries a lot of energy into an abrupt collision. This type of bad technique is almost certainly why people end up saying to use weight instead of pressure. The truth is that it's just the wrong way to use active pressure. That doesn't mean active pressure is always wrong. It's essential for big sounds from contact! The problem is that the fingertips simply resist a very high energy arm movement- thus making no particularly good sense of acceleration through the contact, nor pushing safely back out of the key bed. It's all about a huge input energy plus stiffness, rather than a more sophisticated transmission of power. The sound is loud via brute force. Watch the wrist abruptly jam when the key lands, with nowhere for the energy to go. In truth, it's not wholly unmanageable if used sparingly (and you'll see concert pros who actually use something similar at times), but you'll get into serious bother indeed if you use this technique too much. It should preferably be avoided altogether.
The third demonstration is based on trying to push the knuckles up and AWAY from the contact with the keys. You must bond clearly with the resistance of the key first and then push try to push the bridge of the hand back out and away from this contact. I exaggerated the visible action twice, although the subtler version at the very end is condensed down more. It can even be far more subtle still. Anyway, this slight internal hand movement is what actively throws the tips of the fingers out, thus prolonging the contact with the key's resistance to the fullest opportunity. This is why my arm really doesn't have to push especially hard at all. I can equally use this blend to produce a fairly big sound with next to no perceived effort whatsover, or to make a truly huge sound with only a relatively small and still very manageable effort. Only with many very loud chords in quick succession might this motion even begin to get tiring.
You can reduce the amount of visible movement but you shouldn't be aiming to throw it away entirely. There's minimal impact or exertion, because this continuation takes you AWAY from the collision. Observe how the arm doesn't crash its mass down into a thudding collision at all. At most, it just stabilises the reaction movements. If the wrist were to move down hard and suddenly stop, you would face far more physical impact. The arm instead contributes a forward pressure, but it doesn't itself proceed downward. The continuation is slightly up and out of the point of collision (with gravity as a natural braking force), not straight down into a dead stop point. My wrist ascends a little (but slows before getting higher than the knuckles themselves) and excess energy is absorbed. The slight movement isn't the dangerous part but rather the reason the energy dissipates slowly. The ends of my fingers are literally the only thing going down in space, while everything else is pushed safely back the opposite way. This is the polar opposite of a gravity action. Learn to do this and you'll be able to apply abundant power with very little effort.
Now, here's the rather surprising bit. When I add in the swing of the arm, the hand and arm have to land in what is exactly the same basic manner as how I showed you to play from contact. In the final group, watch for all the same key features I defined in the first film (while first paying as little attention as possible to the relative red herring of the approach)
The first movements sag down pretty uselessly again. Lots of flailing there, but not much energy is making it into the sound. Practise it again to develop freedom in the wrist, but not as a primary technique to use directly. The second style is only even worse now! Maybe try this once (and only once) to experience why this is not the way anyone should be trying to employ gravity technique. But preferably move on and then never look back. Incidentally the "tension to release" description is popular for arm drops, but it's simply a terrible and misleading explanation. Relaxing after an impact already happened would be bad enough without the big run up. On this occasion, giving significant value to relaxing after such a brutal impact would be like imagining it's fine to slit your wrists, as long as you're sure there's a stock of plasters in the bathroom cupboard. If you use this kind of braced landing as a standard part of technique, it's only a matter of time before you should expect to hurt yourself, no matter whether you relax afterwards.
Anyway, watch closely when the landings occur in the third group. The wrist descends solely during the run up. At the landing it starts on the slightly low side, but rebounds while the keys move. We used gravity to help build the speed of hand movement, but that doesn't mean you need to actually land heavily. Yes, the secret to "arm weight" technique is to basically take virtually all the sense of arm weight away, in the split seconds before landing- allowing the hand to push the bridge of the knuckles more upwards and away. You actually need to pull back with the upper arm a fraction before you get to the keys and then let the hand swing free out of a slightly cocked wrist. This throws the hand and fingers outwards (again sending the peak acceleration to the business end), just like the crack of a whip or the casting of a fishing line. It's when you pull back slightly, that the far end really flies out into its main movement. You will see exactly the same when you watch the videos I posted, plus those of Volodos and Rubinstein etc doing similarly massive arm swings. They don't truly fall all the way into the landing itself. The arm lightens in advance and the fingers fly out of the hand. Nowadays you can use slow motion on Youtube, if you doubt that they're actually landing softly, rather than with heavy arm collisions.
Merely relaxing all the way into the landing would take the edge off compared to the previous braced collision but it wouldn't either make all that extra arm energy vanish away, nor would it give you control over the sound. Relaxing just buys a slightly softer impact, rather than an effortless redirection of energy. Would you rather relax everything and fall to the floor mid-stride while running, or push off the landing into your next stride? Actively pushing out is safer than just collapsing into the floor (in spite of the fact that landing onto a stiffly braced leg would be worse still). At the keys the exact same upward redirection as before is taking place. The wrist rebounds a little upwards and therefore the arm energy doesn't crash into a stop at once. The slight throwing out of the fingers creates the springiness that rebounds remaining arm energy effortlessly into continuation upward, rather than into an abrupt collision downwards. I was fairly modest in the size of my movement here, but the basic technique makes it equally possible to generate a lot sound from a minimal run up and to generate even a huge sound from a far larger one (without landing hard in either case). I may come back to post one extra film shortly, in order to prove that I can also do the truly huge movements with this exact same technique.
Most people would need to work chiefly on the basic action of growth out of contact, before they will be able to master landings from a run up. If you do try the bigger and more flamboyant gestures, you should film yourself practising and reference it against my checklist (particularly in terms of whether the arm or knuckles crash downward during the landing). However, with the right awareness of active acceleration, you can start to master those light whipping actions of the arm, as opposed to genuinely arm-heavy collisions. I actually practise this a lot on a tabletop before taking it to the real keyboard, so I can see just how light and springy the landings are. If you're getting any of this right, a table should start to feel more like landing into a fireman's trampoline, rather than missing it and hitting a stone floor!
(I recently tried teaching a lesson through Skype and was pleasantly surprised by how much it was possible to help adjust a student's technique via a video lesson. If this has piqued anyone's interest (and you'd like to know more about how get this technique right) feel free to contact me on firstname.lastname@example.org for more details.)