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Hello all !
I also have heard different statements: backchecks being 2 mm lower than
the hammer tail et letoff , or at drop.
STEINWAY : backchecks height is 2mm under the tail of the hammer (shank at
horizontal, meaning more or less letoff) THEN the backchecks wire is angled
to provide the 72 ° angle, and consequently the height of the backchecks
turn to be more 2mm after drop than letoff.
Why does it add some power or opening to tone , I have 2 ideas.
The backchecks being lower the wire is more rigid, so the bump of the hammer
coming in check is stronger.
This bump arise while or slightly after the hammer have hit the strings,
so it is obvious that if that knocking is happening longer because of lower
backchecks or also lower checking, the bum of the key is prorogated with the
bump of the tails coming in check. I'd suppose that a longer bump gives more
energy to the tone (we are yet in a moment where the tone is not stable may
be even the first wave train is only beginning to move toward the bridge,
nowadays, I suspect we are still in the "energising" moment of the acoustic
system)
The hardness and resiliency of the front punching is more acting as a
mechanical goodie in my view, indeed there is a bum noise with the key
bottoming, but see more efficiency in the system acting in a cycle of
compression/release and then the added firmness is acting like the see saw
(explication : TM Andre)
A harder bottom propulse faster the system.
Landing of the hammer tail does not say much to me, eventually a shorter
wire will provide a harder landing than a longer wire, but in any case the
good checking is when the hammer tail will rub the backchecks (with a nice
scratchy noise) if the hammer is in drop and pushed down slightly, and IS
NOT rubbing the backchecks when rising and being restricted (shank flexed
slightly) with a finger.
If an action get too noisy with firmer punching, possibly the key bed is
in soft wood too resonant, but also the travel/ letoff/drop and backchecks
/dip is not optimum, and the key bottoms too early before the hammer
produce a tone - that is why synchrony between drop and letoff is
unavoidable, that is the only way to compress the system with friction,
limiting any bump and landing noises.
Was it ok friends ?
Best regards.
.
Isaac
Best regards.
-----Message d'origine-----
De : pianotech-bounces@ptg.org [mailto:pianotech-bounces@ptg.org]De la part
de antares
Envoyé : lundi 16 août 2004 21:37
À : Pianotech
Objet : back check, a magical mystery tour.
Hello List, Avery, Stephane and Richard,
I have written about this mystery issue before a long time ago. I personally
have no explanation for it.
I just learned this from a very gifted Japanese teacher. he introduced me to
"the one and only right position" of a back check versus hammer tail.
According to him (Tsuji-san), there should be a space of 2 mm after drop
between hammer tail and back check.
Indeed that is true, and it is a mighty weapon.
Throughout the years, there have been many miracles described on this list
to improve tone and action.
If we delve into all what has been said, we must come to the conclusion
that, to achieve the very best in regard to the way an action performs and
to get the ultimate outcome...the tone, our profession is extremely complex.
The mystery of the back check has not been solved yet. I have as of yet not
heard an explanation that totally convinces me. Nor was Tsuji-san able to
explain it to me.
A very powerful regulation is one thing, to make a fantastic tone another.
Among the weapons we are able to employ are :
1. Our experience, talent, knowledge and understanding first of all
2. The use of high quality materials like : the best felt and the best front
punching (indeed heavily underestimated)
3. A thorough understanding of the use of anti-friction material, and what
it really means
4. The ability to make a superb concert tuning
5. The ability to bring a voicing to a high standard.
As described above, the back check height belongs to this list. It is a very
handy help in the voicing process.
We start this process with the usual list, like anti-friction treatment,
regulation, tuning and voicing, but we can improve the final outcome with
the help of this back check phenomenon.
To give you a clear example :
A long time ago I had to prepare a number of instruments for customers in
the showroom of Yamaha in the Netherlands.
After a few rounds, one C5 grand was their favorite, but they explained to
me that still something was missing.... it was just not powerful enough.
My piano instinct told me to do the one and last thing : I told them to have
another cup of coffee (yes Huber Liverman!) and I also told them that I knew
exactly what they meant.
This was partly true, but also bluff on my side, but under the
circumstances, my professional life was on the block.
I got out my Japanese tool to change the height of the back checks and I
started twisting and turning the back checks to the desired height.
On the way I broke one of the back checks but was so extremely lucky to be
able to replace it immediately and without their seeing any of it (they were
busy slurping their adrenalin).
After 10 minutes, I wiped the sweat from my brows and joined them for my
round of the brown stuff, and I told them that I thought I had successfully
solved their complaint.
They went back and played the C5, and bought it immediately!!
Thanks to the generous lesson of Tsuji-san.
André Oorebeek
On 16-aug-04, at 8:27, Richard Brekne wrote:
Hi Avery
In the case of the grand at the University, they were higher then what
turned out to be best for the sound. I am not sure whether they can be too
low in this regard. Andre is following the whole thread so I am sure he can
answer better.
btw... I've heard the standard set both 2mm above and 2mm below the hammer
tail at let-off through the years. Quite a few times both ways actually. It
would be nice to hear what the consensus is here.
Cheers
RicB
Avery Todd wrote:
Ric,
Just curious. Is Andre referring to the backchecks being higher than
normal
(2 mm below the hammer tail at let-off), or lower?
Avery
This brings me to another one of Andre's suggestions... that about the
height of the backcheck having an impact on tone. Now this one is just plain
weird sounding... I'll be the first to admit it... but there it was. When
Andre was up here a couple years back he demonstrated it to 5 of us, and no
one could avoid admiting that he'd changed the tone... the openess of the
tone on the notes he'd adjusted. I asked the famous Japanese pianotechs Mr.
Ono and Mr. Takahara about this too whilst I was in Japan this summer, and
they both immediatly responded along the lines... "but of course-- didnt you
know that ???"... tho to this day I have yet to find a satisfactory
explaination for why the height of the backcheck can influence the openess
of the tone of the piano.
_______________________________________________
pianotech list info: https://www.moypiano.com/resources/#archives
_______________________________________________
pianotech list info: https://www.moypiano.com/resources/#archives
friendly greetings
from
André Oorebeek
Amsterdam -
The Netherlands
www.concertpianoservice.nl
www.grandpiano.nl
"where music is, no harm can be"
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