Personally, I am still somewhat on the skeptical side of belief that
this effect does occur. This is said with all due respects to those that
report experiencing it but, as I have not experienced it myself, a certain
skepticism persists.
Should the positioning of the hammer tail relative to the top of the
check be so critical as to induce as noticeable a change in sound as is
reported, then the conclusion seems inescapable that the sound would be
varying as checking does or not occur. I am not able to note, in my own
perception, to find such a correlation.
However, if this effect does exist, I would suggest that it occurs not
as result of energy being delivered to any signficant degree to the string
through a so-called pulse in the action, or the waveform output of the
soundboard being significantly modified by the checking, or by dragging the
tail on the check under particular conditions, but, rather as the result of
the well-known masking effect of noises in the action on the sound. I know
others disagree, but, in my opinion, the cleanest, best sound to be produced
as a result of things the pianist controls, is obtained by minimizing all
kinds of noises in the touch, particularly the thump at the end of the
keystroke. Over time, dduring the course of hearing a piano played, as the
noise is kept uinder control, the psycho-acoustic effect of this becomes
more pronounced. That is to say the perceptual effect is far greater is far
greater than the proportion of noise to string /soundboard sound. With no
training whatsoever, or any conscious grasp of this, many pianists
automatically touch the piano in ways which enhance the sound by controlling
just such noises.
Many years ago, while studying piano with Lili Krauss, I was
repeatedly embroiled in controversy with the teacher and her assistant as
they frequently commented that I produced such a "beautiful tone". Being
young and lacking in understanding to an even greater degree than now, I
repeatedly argued that tone was tone and that you could not affect it one
way or the other: it arose simply from the instrument as a result of the
hammer/string contact and that was that.
However, experience soon showed, in audition of the sounds of other
students and elsewhere, that they were right in their commentary - it was
possible to produce a bad sound, even though I was accustomed, apparently as
a result of habits in touch, to produce a good one. Their analysis was that
touching the key in such a way made the difference which was exactly right,
although their concept of touching the key in certain characteristic ways
was incorrect and a misconception of the actual fact that the touch of the
pianist, however made, is superior acoustically if done in a fashion which
minimizes noise, particularly at the botton of the keystroke.
To evaluate this I made a listening device using a stethoscope with a
modified tube which enabled me to attach the pickup to the botton of the
keybed and listen while playing. One can easily hear a tremendous roar, for
example during a trill, or scales, if the pianist continously forces the
key violently onto the punching while playing. Possibly, as I said above,
the effect of the checking location, if real, contributes similarly,
although I am, as I said, skeptical mainly due to the fact that this would
imply a systematically varying tone correlated to whether or not the action
is take into check by the pianist. Checking does not occur all of the time,
or, very possibly, even half the time or less, when the action is being
operated by a pianist, in my opinion.
Although I personally dislike the persistence of OT topics here,
whether cute one liners, friendly acknowledgements for whatever purpose, or
long paragraphs larded with political or religious commentary, I want
briefly, to add my own public appreciation to Sarah Fox for her many very
valuable, lucid contributions which we are lucky to have had and express the
hope that these contributions on her part will continue. I don't believe
Bob G. intended offense in his original post and merely recounted an
unusual, perplexing situation, possibly with a little dramatic license. No
other comment on this or the subsequent postings on this latest OT thread
will be had from me.
Ed Foote's post, under the title, I think, of reality check,
regarding the unavoidable effects of OT postings should be taken to heart
by all.
Regards, Robin Hufford
Richard Brekne wrote:
> Grin... Stephen... this is the second time in a row you struck the exact
> chord that brings an appreciative smile to my innards... :) This time
> its directing us towards the obvious... common sense as it were. This
> explanation doesnt have a lot of sensuality to it... but it does show
> some promise of being in the right ball park.
>
> Stephen Birkett wrote:
>
> > We've seen quite a few 'second-tier' hypotheses - as Ric says, sexy
> > explanations - for the backcheck phenomenon. These things obviously
> > need to be examined experimentally, but a small dose of Occam might be
> > a good thing first. I'm thinking something is causing this that occurs
> > before the string impact. The obvious candidate is interaction between
> > the backcheck and the hammer tail as the hammer heads toward the
> > string. Backcheck clearance is supposed to be pretty tight, and I've
> > seen enough examples of slight catching on the check as the tail goes
> > up, enough that power is lost without it being obvious. For a given
> > action configuration, this effect doesn't occur for all blows. It's a
> > function of various action parameters, including softness of the
> > whippen cushion and other felt contacts, hammer shank flexibility,
> > tail geometry, and so on, as well as the type of touch applied to the
> > key. Lowering the check to achieve the magic 2mm separation may very
> > well ensure adequate clearance in all cases.
> >
> It may very well indeed... especially when the other back check
> parameters are adjusted correctly.
>
> > It's probably possible to check this on a "dud" key before and after
> > making the adjustment of backcheck height, even with just a bit of
> > chalk on tip of the key tail. Static clearance of the check/key tail
> > is certainly no guarantee of dynamic clearance. If it's too subtle for
> > chalk it will need some targeted experiments with high speed images to
> > investigate properly.
> >
> A good suggestion.. and easy to carry out... most certainly at least
> some what revealing. I'm a gonna give this one a try :)
>
> > From the current discussion, it seems the effect is also apparent if
> > backcheck clearance height is too much more than 2mm, and the
> > explanation above doesn't address that of course. To those who've had
> > good results with Andre's technique (including Andre himself), in
> > practical circumstances how often do the checks have to be lowered vs
> > raised?
> >
> Well.. lets see...if the back check is too high or too low.. then it has
> to be moved in the lateral direction and its angle has to be changed to
> maintain the same <<static>> check height and holding strength. So
> maybe.... the 2 mm simply describes the optimum distance for these other
> two directions to also be at their most efficient ??
>
> As far as how often checks need adjusting. Hmm... you'd be suprised how
> varied back check height is off the factory line... even in pianos like
> Yamaha where <<precision machines>> are specially made to do the job.
> Then there is the hammer change job done by the tech down the
> street...... grin.. In short... it happens often enough that they need
> addressing.
>
> > Stephen
>
> Cheers
> RicB
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