Rib overkill

[Greg Newell]

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At 12:31 AM 7/28/2003, you wrote:

>Ya' know...I had this same idea years ago.  The idea was based on the
>violin.  The panels are made of different woods to cater to different
>characteristics.  Maple for stiffness and good high end tones, and spruce
>for bass tones.  I thought about this in relation to the piano.  Maple is a
>tougher wood than spruce.  The top panel made of maple could hold crown
>better (maybe), and give better high end sustain.


Yeah but the panel doesn't hold crown the ribs do.


>While the lower panel,
>made of spruce and crowned downward,  could be thinner and give better bass
>response.  Connect these with a tone pole and you have a pianolin.
>
>Would it work?  Who knows...?
>
>Just a crazy idea I had to use up more wood and drive rebuilders crazy, not
>that they need any help.
>
>Mike Bratcher
>----- Original Message -----
>From: "Joe And Penny Goss" <imatunr@srvinet.com>
>To: "Pianotech" <pianotech@ptg.org>
>Sent: Sunday, July 27, 2003 8:48 PM
>Subject: Re: Rib overkill
>
>
> > ??
> > Has anyone ever made a piano with two boards. Parallel to eachother with
> > different stiffness factors?
> > Joe Goss
> > imatunr@srvinet.com
> > www.mothergoosetools.com
> > ----- Original Message -----
> > From: "Ron Nossaman" <RNossaman@cox.net>
> > To: "Pianotech" <pianotech@ptg.org>
> > Sent: Sunday, July 27, 2003 7:28 PM
> > Subject: Re: Rib overkill
> >
> >
> >
> > > It can. A more flexible board will tend to be generally louder, with
> > > shorter sustain. A stiffer board will tend to be not as loud, with
>longer
> > > sustain.
> > Will the bass suffer?
> > >
> > > Yes. If there is to be any hope of getting a fundamental out of the=
 low
> > > bass, the board needs to be flexible down there, and the back scale
>needs
> > > to be long, and the core wire needs to not be the diameter of an 8d
>nail.
> > > At the same time, the treble needs to be stiff or you will get the
> > > percussive attack and short sustain of the "killer octave" through the
> > last
> > > two octaves or so. Stiffness requirements are widely different from=
 one
> > end
> > > of the scale to the other.
> > >
> > >
> > > >I think I also remember Del mentioning something about a board giving
>too
> > > >much of a percussive sound and not as much string sound.  Is this=
 with
>a
> > > >board that is too stiff?
> > >
> > > Probably too flexible.
> > >
> > >
> > > >How does the thickness of the board relate to how much load it can
> > support?
> > >
> > > It depends on the crowning method. A compression crowned board will be
> > > stiffer with a thicker panel, and support comparatively more load than=
 a
> > > compression crowned board with a thinner panel. With a rib crowned
>board,
> > > assuming it is really rib supported and not just a compression crowned
> > > board with machine crowned ribs, the panel thickness makes much less
> > > difference. With a rib crowned, rib supported board, there is no need
>for
> > a
> > > thick panel if the rim is solid.
> > >
> > >
> > > >And in relation to the rib thickness?
> > >
> > > Again, it depends on the crowning method. Compression crowned boards
>tend
> > > to have ribs wider than they are deep, because they start out flat and
>the
> >
> > > panel expansion has to bend them to form crown. Rib crowned and
>supported
> > > boards will have ribs less wide, and deeper, regardless of panel
> > thickness.
> > > Ribs get stiffer in proportion to their width, and to the cube of=
 their
> > > height (and inversely to the cube of their length), so a little bit of
>rib
> > > height makes them a lot stiffer.
> > >
> > >
> > > >I'm sure all these things are interrelated.  What are the trade-offs?
> > >
> > > Those are some of them.
> > >
> > >
> > > >Next, I'm sure the size of the board is a factor.  A smaller piano=
 will
> > > >have more support from the rim, because the there is more rim per=
 area
>of
> > > >board.  Yet another factor to consider, aye?
> > >
> > > Absolutely. Soundboards, contrary to manufacturers' marketing=
 literature
> > > bragging about how their soundboards have more area than their
> > > competitors', are for the most part already too big. Redesigns I do
> > > typically lose something around 20% of the existing active soundboard
> > area,
> > > depending on what I started with.
> > >
> > >
> > > >How does one judge or weigh the trade-offs?  There are so many
>variables.
> > >
> > > A bunch of variables, the most critical of them not the ones we have
> > always
> > > been taught were all important. One can either put in a couple of
>hundred
> > > soundboards, making incremental-to-major changes in virtually=
 everything
> > > until he works out a set of priorities and effects of design features,
>or
> > > he can do what I did and start rethinking what I thought I knew=
 against
> > the
> > > good fundamental science and physics based advice and guidelines of
> > someone
> > > who did do the basic R&D from scratch. That would be Del.
> > >
> > >
> > > >There's no real point here to my questions.  I am always trying to
>learn
> > > >more about my trade.  And who else do I learn from other than the=
 folks
> > > >who do this every day?
> > > >
> > > >Mike Bratcher
> > >
> > > Every day's a new day for all of us isn't it? There's always something
>to
> > > learn - and heal up from.
> > >
> > > Ron N
> > >
> > > _______________________________________________
> > > pianotech list info: https://www.moypiano.com/resources/#archives
> >
> > _______________________________________________
> > pianotech list info: https://www.moypiano.com/resources/#archives
>
>_______________________________________________
>pianotech list info: https://www.moypiano.com/resources/#archives

Greg Newell
Greg's piano Fort=E9
mailto:gnewell@ameritech.net=20

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