[CAUT] Syllabus in Piano Technology

[Richard Brekne]

Hi Jim.

Using springs instead of or to compliment front key leading in itself is 
not such a big deal. We see that all the time. Even oldtime Steinways 
employed helper springs to adjust touchweight. In your case its more a 
question of why the backweighting ?  But then you are talking about an 
instrument from the Danish piano building tradition and they, like 
Scandinavians in general were into trying out many things not so common 
in the mainstream of pianobuilding.... not that I know for sure that is 
related to your case.

You'd have to disconnect the strings and find the ratio of this action 
for us to be able to really get into it with you.  Could be they had 
this really high ratio and very heavy hammers idea.... :)  who knows ?

To my mind of thinking... any assist method be it  springs or magnets... 
should only be asked to do very minimal work and that just to "fine 
tune" existing touch weight uneveness.  In the end its the dynamics of 
touch weight that the pianist is going to react to most. Using lots of 
hammer mass is going to be felt one way or the other no matter what you do.

I'd like for curiosity sake to get a complete set of 10 sample 
measurements ala Stanwood. Might be fun to see what you got there :)

Cheers
RicB

    All,

    I have an action (Hornung and Moller 1972) that has one or two leads
    in the very back of the key and no lead in the front. It has wippen
    helper springs. DW is around 65 - 70 and UW is around  36 - 40 or
    so. (Friction seems to be ok, but BW is 50 - 55!!)

    I don't know why the springs were adjusted for this weight, and I
    can adjust the springs to achieve a good weight (50-20 or so) but my
    question is a very basic one; Why would you use springs instead of
    leads to touchweight the action? What does this do to the MOI? Or,
    at the very least what is the difference in feel between a "spring"
    vs. "lead" touchweighted action? And, why do one over the other?

    Fred, Ric, enlighten me!

    Jim Busby

    P.s. I experimented and put weights in about 8 keys and a normal
    leading pattern makes it work...normal.