The Soundboard bit.. RC&S

[David Love]

Stephen:

I have not yet seen the article in the December journal (not received yet)
but I'm interested--though not yet committed.  I'm not quite clear on
exactly what role you envision for the victim/participants?  Do you have a
"suitable set of quantitative measures" in mind or are you looking for what
those might be?  That set, it seems, should include a set of dynamic as well
as static measures.  Have you considered what those dynamic measurements
might consist of?  Are you looking to have people build the boards in each
category or take measurements from boards that have already been built?  One
potential problem I can see is how to create "otherwise identical" panels.
If you attempt to match the pre calculated crown that forms on a straight CC
board by design on an RC&S board, for example, the variability of just how
much crown forms on any given CC panel could present a problem.  Also, one
of the issues is compression set and what happens to these panels over time.
How is that likely to be measured in a practical way? 

Those are the things that come immediately to mind.  I'm sure other things
will occur to me the more I think about it and there are those on the list
who, I'm sure, have thought about these issues in much more depth and for
much longer than I have.  But there is no question that a project such as
you describe would yield some interesting data.    
   

David Love
davidlovepianos at comcast.net 
www.davidlovepianos.com

-----Original Message-----
From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf
Of Stephen Birkett
Sent: Tuesday, December 12, 2006 2:12 PM
To: Pianotech List
Subject: Re: The Soundboard bit.. RC&S

Ron N:
>.... Should anyone out there wish to throw sufficiently large 
>quantities of cash at me that I don't ever have to work for a living 
>again, and can afford the space, equipment, and materials to pursue 
>it, the R&D could progress at a much accelerated pace.

David L:
>As Ron N said, give me enough money that I don't have to worry about 
>making a living anymore and I'm right there with him doing all the 
>real research and providing real data that will further enlighten us 
>on the subject.

Ron N:
>Standing by for offers...

Well I am not in a position to be a benefactor guys. (We do have the 
Medici's to thank for supporting BC for all those years while he 
tinkered away with his piano invention in the first place.)

However, I AM in a position to offer research resources. I have a new 
graduate student whose project will focus on soundboard design for 
two years. He'll be investigating some of my (weird) soundboard ideas 
for the post-modern piano being designed here. And I have all kinds 
of measurement equipment and lab resources available for free. It 
would be quite feasible to add on some experimentation with the ideas 
that have been tossed about recently, and so many times before, on 
the extent to which compression and crown affect soundboard response, 
as well as the nature of that influence.

How to proceed?

Well, if you've seen my article in December journal, you'll see my 
views about research and how technicians should be involved in the 
collaboration. We should agree together on a set of specific design 
questions that can be tested experimentally. Between the various 
names that have contributed to this most recent thread we can surely 
put together a good investigative project, varying specific factors 
and measuring the change in behaviour they cause.

The time for this work now, because grad students turn back into 
pumpkins at midnight (when they graduate). So, if I put the time in 
to supervise this research here and my grad student does the work on 
the experiments, all we would need from you guys is soundboards of 
various types to study, made according to your normal practices and 
methods. If we can agree in principle let's start thinking 
specifically what we can test and how we can best do it, as well as 
how to target variation in a single design factor at one time.

An idea that comes to mind immediately would be a direct comparison 
between three soundboards otherwise identical (ribs, geometry, 
material, crown): (1) heavily CC, (2) RC, with a teaspoon of CC, and 
(3) RC&S with only a dash of CC. As far as possible all three should 
be designed to give the same crown at typical operating ambient 
conditions. So as to keep the mass and height of the ribs essentially 
the same i suggest: (1) has flat ribs, (2) is radiused to give a 
similar crown to (1) at a semi-severe drying level (you guys who make 
these things must have some feel by now for how these things are 
going to come out), and (3) is radiused to match the crown of (1).

So, between you all, can you guys put together the victims? Terry? 
Dave? Ron? Del? Dale? others? [Ric is exempt since he's lurking away 
in Scandinavia]

Who wants to take a stab at a suitable set of quantitative measures 
to characterize the behaviour of the boards in meaningful piano terms?

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. 33792
Lab room E3-3160 Ext. 37115
mailto: sbirkett[at]real.uwaterloo.ca
http://real.uwaterloo.ca/~sbirkett