HammerWt/Tone

[stanwood]

John Hartman Wrote:

>Don't you think it would be better to refer to hammer weight in terms of
>actual grams instead of using imprecise terms like heavy or light?


John,

This is an excerpt from my posting of 1/11/95 regarding precise definition
of hammer weight in terms of the newly defined term "Strike Weight".
If you haven't read this post, the discussion we've been having in regards
to leverage ratio etc might be confusing.

I'd be happy to forward you a copy of the posting.  Just let me know:



                 STRIKE WEIGHT RANGE GUIDELINES:

Note   1          22          44          66          88


       14.8-------13.7-------12.1--------9.8---------6.9
         F U L L       T O N A L    P R O J E C T I O N
       12.4-------11.5-------10.2--------8.3---------5.8
         M E D I U M   T O N A L    P R O J E C T I O N
       10.3--------9.5--------8.4--------6.7---------4.6
         L O W         T O N A L    P R O J E C T I O N
        8.0--------7.4--------6.5--------5.2---------3.5

Note: The hammer weight may be found by
subtracting the shank strike weight from the strike
weight.  The shank strike weight is the weight of the
shank taken at the strike line radius.

Shank strike Weight is generally around 1.8 - 2.0 grams


>I certainly can't agree that a heavy hammer is required to have a powerful
>tone. I have witnessed many examples of truly powerful pianos with light
>cold pressed hammers.

I quarantee that if those powerfull pianos with light hammers were put in
Symphony hall for use in a piano concerto the result would be a disaster.
Think about this: If the strike weight is brought to zero the tonal power
will go to zero, so there has to be a point were tonal power diminishes as a
function of weight.

>At the bottom of this is probably some very simple and elegant relationship
>between leverage, hammer weight and friction and some sort of equilibrium
>between, key acceleration, hammers acceleration and the hammer's >compliance.

The relationships that I have given for strike weight and strike ratio are
part of a unified touchweight formula that discribes the contribution of
each part of the piano action in terms of weight, leverage, and even
friction.  It is what I am calling "The New Touchweight Metrology".
When my key balancing patent is issued the full discription of the formula
will be published, and in fact I am close to a point were I may publish
before the patent issues.

>When all's said and done we may find our selves going back to using hammers
>that are neither heavy nor light but just right.

We find that hammers over a wide range (as shown in the table above) will
work in pianos.  The individual situation must dictate what hammer weight is
appropriate.  The best we can do is collect as much qualitative and
quantitative information as we can for a given situation and make the best
decision we can make based on analysis of that information.

It is certainly in the best interest of pianist to see manufacturers adopt
more specific standards than they are currently using with regards to hammer
weight, action ratio, and key balancing parameters.

David C. Stanwood