Hi,

Firstly, congratulations on some excellent work. It's great to have some solid empirical evidence to support these issues- especially in terms of the nature of rhythmic and tonal control. My own background is first and foremost as a musician and teacher (and I'm certainly not set up do the kind of laboratory testing you have performed here) although I also write on the subject on technique in reference to issues of mechanics, based on my own original research.

If I may, I'd like to illustrate a concept that I have recently narrowed down to a very precise form, about the nature of what pianistic efficiency really is. I think it would be very interesting to view your data in reference to this alternative viewpoint, as I'd personally have to quibble on aspects of your basis for defining "efficiency". My definition is based on a very simple logic based premise for the efficiency of what passes speed specifically into the key- rather than on what moves each joint in the direction of the key. This is important pianistically- as anything that sends the knuckle itself towards the key can be an innate problem. It would be interesting to know more about the exact context of what was being performed- as I was very surprised to see a descending defined as efficient in high speed playing. In an ongoing series of notes, if the knuckle travels towards the keys, is that really efficient? Pianistically, probably not- as it suggests either significant rotation or "squashing" of the hand. Hypothetically, rotation might sometimes cause this but would it always be possible to lower the playing knuckle in space routinely? Probably not- as sooner or later you have to reset- to stop the whole hand collapsing down. Also, as I'd like to illustrate, having the knuckle potentially moving up and away in no way suggests true inefficiency. If we view the matter in terms of speed transfer, it's often a clear characteristic of the MOST efficient speed transfer- that directs the largest individual speed attained anywhere in the mechanism, to the point where the tip accelerates the key.

Anyway, to clarify a solid foundation behind these concepts, please see the definitions of "positive movement" and "negative movement" (my own terms for what I've defined).


http://pianoscience.blogs...


The start of the post gives very explicit definitions of the concept in a highly concise form. However, the proofs are a little more spread out in a long post, so I'll give a concise run down of why I think it's vital to see "efficiency" through this specific viewpoint. I think the first category (with a lengthened finger) is self-evident, but for the second, it's a matter of speed transfer. A compressing finger creates larger speeds elsewhere, than at the point where the tip is moving the key (as can be seen by the fact that the knuckle is, in relative terms, accelerating towards the finger-tip- which is therefore travelling slower though the key). That is inefficient, because the fastest speed is wasted. It seems to me that if we define efficiency by whether all the joints move in the line of the key, it rather misses the point. Not all joints need to be travelling in a specific path. The key is that speed actually reaches the fingertip end during acceleration- otherwise any additional momentum merely goes into impact upon arrival at the keybed, without generating extra hammer acceleration.

On this basis, if the knuckle moves towards the key, there's often notably LESS efficiency. Were the finger rigid, the same speed at the knuckle would thus reach fingertip and key. But were it expanding (so tip and knuckle are moving apart) then the tip is therefore generating the highest speed of all. Additionally, if we consider impact, there's much more when the knuckle is actually travelling down- which is why good pianists very often expand up and away for a loud chord, rather than press everything down through the direct line of motion. Movement away from the line of motion is not in any way "inefficient" (as your chosen viewpoint would suggest). It channels the greatest speed to occur directy to the key, without pressing everything else down into impact. Importantly, an expansion sends additional momentum away from collision, rather than into compression- hence being more healthy.

Similarly, in relation to efficiency, viewing it in terms of extension of the DIP/PIP doesn't really differentiate properly between good and bad. The slow pianist is guilty of a classic case of "negative movement" (the distance between knuckle and tip is being squashed rather than either preserved or increased- thus inefficient and unpredictable speed transfer to the piano). Clearly that pianist is pressing with the arm and failing to pass their highest speed to the key itself, during transmission. On the other hand, the fast pianist's mild lengthening increases the distance- thus guaranteeing that the highest speed attained anywhere is right at the point where the key is accelerated. Personally, I largely agree with Beauchamp- but as long as a willful extension of those joints contributes to growing that distance, it can add to efficiency. Only shrinking that distance reduces it. The mistake is to squash the finger with arm pressure and have that violently collapse the finger- not to be striving to lengthen the joints.

Also, one more point- I'm a firm believer in lengthening the joints slightly, while the knuckle provides the flexion, but I was confused by the video. The fast pianist seems to be closing all of his joints inwards? I'm a little puzzled, as it doesn't seem to be doing what is referred to in the results. Is the pianist lengthening slightly and then switching to a flexion of joints, or is the video simply not the most representative of the lengthening spoken of in the results?