Unusual rib structure?

[Farrell]

Hi Ron. Just FWIW, these Wissners almost remind me of a Decker Bros. piano. They make most 9-foot concert grands look like play toys. Very massive rims and framing. To the best of my knowledge, these are Steinway clones, as I think I heard that Mr. Wissner worked at Steinway for some period of time. But clearly, they are not cheap imitations, but rather a nice foundation to build a really nice piano! (I wish I owned one!)

Terry Farrell
  
----- Original Message ----- 
From: "Ron Overs" <sec@overspianos.com.au>
To: "Pianotech" <pianotech@ptg.org>
Sent: Tuesday, May 06, 2003 6:43 PM
Subject: Re: Unusual rib structure?


> Hi Sarah,
> 
> Its an interesting piano you have.
> 
> >OK, there's something about my piano (1933 Wissner 9') that 
> >seems odd (in my limited experience), and I've just got to ask.  My 
> >soundboard ribs have an unusual structure (I think), and I'm 
> >uncertain as to the purpose.  Most of the ribs are "tied" together 
> >with one of two small cross-braces.
> 
> I can't see how the ties can do anything to either enhance the 
> structure of the board or its function tonally. They remind me of the 
> tie strap across the bass corner ribs of a model B Steinway, which 
> also are of doubtful benefit.
> 
> >  Counting from the keyboard, high treble end of the soundboard, the 
> >first brace starts around the center, keyboard-end of the soundboard 
> >at rib 8 and continues leftward and towards the tail through rib 13. 
> >Then from the other end of rib 13 (right side of the piano), another 
> >brace starts and extends towards rib 17 in the tail.  Ribs 1-7 and 
> >rib 18 have no cross-braces.
> 
> An 18 rib design, while the D has 17 in the latest offerings at least.
> 
> >   Here are some photos:
> >
> ><http://www.wonderfulhome.info/soundboard1.jpg>www.wonderfulhome.info/soundboard1.jpg
> ><http://www.wonderfulhome.info/soundboard1.jpg>www.wonderfulhome.info/soundboard2.jpg
> ><http://www.wonderfulhome.info/soundboard1.jpg>www.wonderfulhome.info/soundboard3.jpg
> 
> Looking at what appears to be the fifth rib from the bass Sarah (the 
> rib which in jpg 3 runs to the top LH corner of the image), the rib 
> appears to be quite deep in the centre. They look suspiciously like 
> they are rib crowned. Would you mind measuring the overall rib depths 
> at their centres? I'd be interested to know what they are.
> 
> >
> >The ribs on the cross-brace end are not smoothly tapered the way I 
> >think of most ribs being.  Rather, they are reduced in tiers, and 
> >the cross-braces run across the tiers.  The rib ends without 
> >cross-bracing are tapered in the conventional manner.
> >
> >So...  Why was this done?  Was it a way of stiffening the soundboard?
> 
> I would speculate that the designer was interested in achieving a 
> graduation in the sudden reduction of the rib section modulus of a 
> conventionally feathered rib. The stepped feathering would probably 
> cause the panel deflection to be somewhat more progressive. Mind you, 
> this may not necessarily be desirable. For me at least, the 'jury is 
> still out' on this matter.
> 
> >.  The bass on this piano is incredibly rich, powerful, and mellow, 
> >and the sustain is unbelievable.
> 
> The tiered feathering should allow quite a substantial impedance 
> reduction in the panel behind the bass bridge. I would expect this 
> piano to have quite a dark tone in the bass.
> 
> I'll be interested to hear other observations of others re the feathering.
> 
> Ron O.
> 
> -- 
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> 
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> Grand Piano Manufacturers
> 
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