Steingraeber factory pictures, bridge agraffes & adjustable vertical hitchpins

Stephen Birkett sbirkett at real.uwaterloo.ca
Fri May 5 11:33:31 MDT 2006


Ron wrote:
>Strikes me as smoke and mirrors. Notice that Anderssen built " a 
>mathematical model". Did he build a real-world model on the bench? 
>While Anderssen has made certain claims, there is nothing offered by 
>either Stuart or Anderssen in the way of oscilligrams or other such 
>results to support their claim. If they had any hard evidence it 
>would surely have found its way into either brochures or the Stuart 
>website. But there's nothing, just the claim.

A mathematical model - no matter how sophisticated - has little value 
in characterizing the behaviour of a real physical system unless it 
is validated. Applied mathematics is not engineering so a 
mathemaitcal model on its own can "prove" nothing about an 
engineering system. Validation requires experimentation. You check if 
your model predictions (abstract mathematics) are consistent with 
observations (physical behaviour)? Only then can you have any 
justification for extrapolating and using the model as a predictor 
under conditions not experimentally tested directly. Without 
experimentation a mathematical model is only mathematics.

As far as I am aware no experimentation was done to validate the 
string model developed by Anderssen.  An equally serious difficulty 
is that the model itself does not seem to have been published and 
made available for scrutiny. Last I heard when I contacted the author 
in 2004 was that he was planning to publish it soon, but so far I 
haven't seen it appear in any journal and there is nothing available 
online that I can find. So basically it is a secret model that has 
not been experimentally tested. Not very convincing for now at least.

In this case a model is the icing on the cake.  A definitive answer 
to test all the theories can be had with a very simple experiment 
using high-speed imaging equipment. The camera has no agenda to prove 
and shows only what is actually happening. Doing this on a 
multi-string monochord would be interesting for sure, but not 
necessarily definitive, because the subject studied must be as close 
as possible to the real system for the strongest conclusions. That 
means we need to have a bridge agraffe piano (Stuart or Steingraber) 
in the same room as the high-speed equipment.

Anyone know if there will be one in Rochester?

Stephen
-- 
Dr Stephen Birkett
Piano Design Lab
Department of Systems Design Engineering
University of Waterloo, Waterloo ON Canada N2L 3G1
tel: 519-888-4567 Ext. 3792
Lab room E3-3160 Ext. 7115
mailto: sbirkett[at]real.uwaterloo.ca
http://real.uwaterloo.ca/~sbirkett


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