Pinning on new flanges

Richard Brekne Richard.Brekne@grieg.uib.no
Mon, 30 Aug 2004 19:45:59 +0100


Holy Chrasimus Sarah... :)... you do let these things get to be 
gargantuan in length.....

I will try and split this up into a few different replies... for the 
sake of oversiktlighet.

Sarah Fox wrote:

>Hi Ric,
>
>You miss my point.  Perhaps I'm a bit verbose, so the point gets lost.
>Brevity is certainly not my strong suit!
>
>You and others say that the pianist exerts fine control over the depression
>of each key, except for the very fastest passages, played by the most
>advanced, exceptional pianists.  Correct?
>
>I am asking:  HOW?
>  
>
Now... thats what a call a big question.  And if I could give you a 
satisfactorilly complete answer I suppose I would have answered one of 
the mysterys of piano / pianist interreaction that has been argued back 
and forth for like ever. 

You ask a lot of hows below.  Let me add a few.  How is it that pianists 
can demonstrate that they can feel the voice of the piano ?  How can the 
pianist sense a 1 gram difference in static down weight just by playing 
? Why do pianists continually defy phsyisists in a myriad of touch 
issues ? 

I dont really know,,,, but it these things can be observed.. so instead 
of trying to question the validity because I find it difficult to 
establish a mathematical model to explain some or another fact... I 
simply accept things at face value and get on with things.

>Let's say a keystroke takes 1/10 of a second.  That's pretty moderate, I
>think.  Agreed?  That's 100 msec.  Now, let's say that when my finger first
>lands on the key, something is very wrong with the pressure I am exerting,
>but of course my finger is moving downwards, depressing the key wrongly
>until I can do something to correct the error.  Right?
>
>OK, let's say that my reaction times are lightning fast -- as lightning fast
>as they were in my youth.  As I recall (and my memory fails me to some
>extent), I was logging reaction times on the order of 65 msec on one very
>simple psychometric test.  The test?  Press a button when a light comes on.
>Mind you, visual info races to the brain much faster than tactile info, so
>my reaction time would even be longer to some sort of somatosensory event.
>But we'll say it's 65 msec on a very good day.  That means that I'm not
>going to be able to execute any sort of correction until I'm 2/3 through the
>duration of the stroke.  I don't know how this would translate to key
>travel, since we can hardly assume constant acceleration.
>  
>
Like I say... sounds good on paper... but since pianists actually DO 
exert said control, something must be wrong with your scenario.  I would 
submit that your whole perspective of piano playing being simply 
reactive is in error.  Pianist exert control willfully... with purpose.  
They go into a key stroke knowing what they are after.  Your scenario, 
simply underlines the fact that it MUST become increasingly difficult to 
exercise any degree of control for each decrease in the time window the 
pianist is allowed to begin with. Lowering friction does exactly that.  
Turning that arguement around on itself and saying ... well it doenst 
make any difference to begin with because there is no control issue in 
the first place is just not going to fly. You try telling that to the 
pianists of the world.  Besides... if there is no significant affect on 
control, then there most certainly can not be and significant affect on 
the flip side of that question.... you shoot yourself in the foot as far 
as I can see.



>I *will* grant you one thing.  You imply from your previous post that this
>sort of rationale is too cognitive and that it's more of an innate thing -- 
>still involving feedback.  However, an anticipatory spinal reflex takes
>about 55 msec to begin.  That is, when a young, healthy, quick undergraduate
>student volunteer is told to maintain a given pressure on some object and is
>told to be prepared for the object shifting position.  When the object is
>suddenly shifted, it takes about 55 msec for him to *begin* to compensate.
>So that's indeed a bit faster.  But still, is it fast enough?  I mean, the
>hammer is well on its way to the string already!
>  
>
But you are still in the purely reactive mode. And are still simply 
makeing my point better then I could make it myself.  Decreased friction 
levels compound the ability of the pianist to react to anything 
unexpected.  Since nothing about this decrease in friction can enhance 
the general consistancy of the action play, we must assume the pianist 
will meet just as many unexpected moments, and now have an even harder 
time dealing with it then before.  Assuring that  piano output 
corresponds to the intension of the pianist as said acts upon each and 
every key becomes just that much more difficult.

>OK, with this scenario, someone MIGHT be able to exert SOME (but very
>little) control over the depression of a single key, during a 100 msec
>keystroke -- and down to perhaps a 60 msec keystroke (but not very likely).
>
>Now imagine the reflexive control of ten fingers, all doin' their respective
>stuff.
>
>Add to that the fact that irregularities in action response are not going to
>be apparent until after the action starts moving, which adds to the total
>response time.
>
>Now let's increase key velocity, having the pianist play louder.  Still
>think reflexes and feedback loops can keep up?
>  
>

Reflex... reaction.... re-- re--- re----   Thats not what pianist touch 
control is about.

What the pianist does... he/she does (hopefully) on purpose.  Lowered 
friction simply (and by your own analysis as well) makes it increasingly 
difficult to accomplish what they attempt.  Any error... misjudgement... 
whathaveyou gets <<enhanced>> by the very thing you self show becomes 
more and more impossible to react to.

Cheers
RicB




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