High tension? Low? Board stiffness? was Hammer Types

[Ron Nossaman]

> In the recent hammer types thread David Love and others talked about 
> high-tension and low-tension scales. Quantitatively what does that mean? 
> I'd like to see some actual, real-world parameters as to the upper and 
> lower limits of tension for high-tension and low-tension scales. Would 
> these parameters change correspondingly as the size of the piano changes?

Hi Alan,
It depends on who you talk to. I've seen an old type 1 
Steinway D (85 note) scale that totaled about 33,000 lbs, with 
plain wire between 130-140 lbs and an A-7 length of 49mm, to a 
9' Everett totaling about 48,300 lbs, with plain wire between 
180-220 lbs and a C-8 length of 58mm. I'm quite sure those 
aren't either the upper, nor the lower limits, but these two 
pianos will need considerably different soundboard designs to 
accommodate these scales.


> Ditto for inharmonicity.

Inharmonicity is what is left when all the other parameters I 
am concerned with are accommodated as well as I can. Minimal 
differences across scale breaks is vastly more important than 
what the numbers are, in practice.


> While we're at it, can soundboard stiffness be evaluated (at least 
> qualitatively) on your basic fully-strung piano in someone's living 
> room? 

Yes, again, depending on who you talk to and their individual 
standards of what constitutes acceptable piano tone. I do it 
automatically with every piano I tune, and take it into 
account when voicing. I listen to it.


>What are the major factors that define stiffness? 

Panel compression, crowning method, rib number and size, 
bridge height, proximity of bridge ends to the rim, etc.

>Does downbearing play a role here? 

Yes, much more so in a panel compression supported board than 
a rib supported one.


>I'm looking for an answer that has specific, 
> measurable quantities like, "A stiff system has ribs spaced x inches 
> apart with each rib notched into the rim. Ribs are x inches in profile 
> under the long bridge tapering to x inches then tapering to x inches at 
> the rim. A stiff board is x inches thick under the long bridge tapering 
> to ......, whereas a flexible system ..................." And also, "X 
> piano brand is a good example of a stiff system, whereas x pianos use a 
> more flexible system..........." You get the idea.

Yes, I do, but there is no "get out of jail free" card or 
checklist that will give you a binary yes/no gage. You have to 
understand how the thing works and make a judgment call based 
on a lot of factors.


> The other thing in this thread that got my attention was the description 
> of the hammer types matched to the Walter scale. I installed a set of 
> Ronsen Wurzen hammers on a Baldwin L last year. I would characterize the 
> sound as being darker and colorful, and maybe needing a little juice 
> especially in the top 2 octaves for a bit more definition. Needling was 
> not even a consideration for these hammers on this piano . But David's 
> description of the Wurzens on the Walter paints a very different picture 
> of Ronsen Wurzens. So what gives? Is there a lot of difference in 
> Wurzens from set to set? Or is it that if we were to put the same 
> Wurzens on the Baldwin L and then the Walter, we would have "dark" 
> hammers on one, but "bright" hammers on the other, the explanation being 
> that the tone produced is a function of the interaction of the hammer 
> with the board system? Is it possible for their to be enough difference 
> in the board system to produce such different tone (needling like hell 
> vs. maybe needing a bit of juice) from the same type of hammer (assuming 
> the hammers are identical)?

Because hammer choice and voicing is damage control. It's the 
very last chance on the list to salvage whatever small portion 
of tone potential is left after the string scale, soundboard 
design, and age have done their damage. When Phyllis Diller 
goes to the hairdresser and says "Just make me beautiful", The 
same hairdresser with the same tools won't get the same result 
with Phyllis as with, (insert personal favorite endorphin 
inducer here).


> Trying to educate myself. Thanks for any responses and thanks also to 
> David for initiating this interesting thread.
> 
> Alan

All this has been discussed exhaustively thirty or forty times 
on Pianotech in the past. Spend a month reading the archives 
(instead of one of us spending the next month typing it all 
again), burn the necessary brain cells, and put the pieces 
together. It's a demanding but extremely interesting journey 
for anyone willing to do the work necessary to begin to 
understand the system.

Ron N