Grand regulation...

[Richard Brekne]

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What you call setoff, Americans call letoff, and what you call letoff,
Americans call drop. I think its best to use the American terminology
since the list is so dominated by Yanks. Otherwise.. terms are fine.
Striking distance everyone understands as blow. Whoosh :)

The specs you give are bad...but not the worst I've seen. 1/8th letoff
is about 3 mm, and is definantly on the long side, as is drop. Check is
gettin down there for sure.

How do you know that these are factory specs tho ? Is this a brand new
instrument fresh out of the box ? Could be just that it needs a rather
standard dealer prep eh ?

For standard specs.. I like 1.5 -2 mm letoff, that much again for drop,
and 10-12 mm check. I like a firm rise in hammers after check.. but not
hopping, and it shouldnt be very noticlble at the key front by the
finger. Key dip ends up being a function of blow distance, and I use
10mm as a standard and adjust blow to fit.

If I want to get more persnikity about things...then I have to use a
bunch more time then what a standard seat of the pants time regulation
allows for.

Getting a Petrof to do well in a true concert situation is another
matter tho. And if you look close enough at a Petrof action you will
most often find that the degree it  deviates from standard regulation
specs is the least of your worries.

Cheers

RicB

Michael Gamble wrote:

> Hello all. This is an attempt to get some input from those who (that
> means all of you I guess) frequently regulate grand actions. From the
> start we have a few hurdles to get over and of these the principal one
> is that of terminology. In regulation you get a) the parts which are
> being regulated and b) the name given to that part of the regulation
> process. Are we at one with the name "striking distance"? which should
> be about 1 7/8" Then we have "Set-off" In this part we adjust the
> "Set-off Button" until it touches the toe of the "Jack" and causes the
> hammer to stop rising and go into the "escapement" mode.This Set-off
> happens about 1/16" below the string. Next we have the "Let-off" (I
> think that's sometime called "Drop") when the hammer after hitting the
> string is allowed to subside another 1/16". Not to be confused with
> "Check" when the hammer after hitting the string more forcibly
> rebounds into the loving grasp of its check-block. If then, whilst the
> hammer is captivated in check you gradually release the key the hammer
> should float upwards - not too fast. This we call "Hammer rise"..
> OK?The point of all this is I went to tune a new Petrof grand the
> other day and was amazed by how much this Czechoslovakian manufacturer
> had deviated from what I considered the "norm". The results were as
> follows:Striking height 1 7/8" (OK)Check 13/16" ?Set-off
> 1/8"!!!Let-off 3/8"!!!!And the hammer-rise test showed that all the
> hammers came up faster than you can say knife!Here's the question
> therefore -What are the correct settings?My Steinway service manual
> adheres pretty firmly to my first list of requirements except that the
> "Let-off" is considered with relationship to the diameter of the
> string affected.Oh yes - there's another aspect of regulation. It's
> vital that the "Key depth" be correct. Steinway recommend 9.75 on
> models S - B and 9.75mm on C & DReblitz, on the other hand, is a bit
> more "global" in his approach giving more latitude.At the end of the
> day does the piano react as a concert pianist would expect?Over to
> you.Michael G (UK)

--
Richard Brekne
RPT, N.P.T.F.
UiB, Bergen, Norway
mailto:rbrekne@broadpark.no
http://home.broadpark.no/~rbrekne/ricmain.html
http://www.hf.uib.no/grieg/personer/cv_RB.html


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