out of tune Wurlitzer (corrected version)

[Delwin D Fandrich]

The first line of my post below should have read: "With all due respect to Hal Lyne, soundboards with that style of rib
installation are no MORE prone to loss of crown than are any other."

Sorry about that... a loose connection between the brain and the send button.

-- ddf

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Delwin D Fandrich wrote:

> robert moffatt piano service wrote:
>
> > This bit 'o wisdom was passed on to me from my mentor's mentor, Hal T.
> > M. Lyne.  Hal noticed the same problem in Wurlitzers that are 20+ years
> > old.  The problem, in Hal's experience, was that the ribs which support
> > the soundboard (giving it its 'crown') are not embedded in the case;
> > they are simply slapped onto the back of the soundboard.  After time,
> > because there is no additional reinforcement from the case, the wood of
> > the ribs and soundboard simply 'gives out' and the downbearing on the
> > bridges flatten the soundboard.  Ergo, the whole danged thing goes flat.
> > So, check the ribs and see if in fact they are just slapped on the
> > soundboard.  If so, then that's probably why the thing has started to go
> > flat in odd places.
> >
> > How do you fix it?  Don't ask me.  I'm just an apprentice and have
> > enough trouble setting a concert temperament.  Of course, I don't have
> > any flashing lights to help me out so it's taking me a little longer to
> > learn.  Then again, I hope to be a better tuner for it, neh?
> >
> > If you've any questions about possible repairs, you can E-mail my boss
> > directly.
> >
> > Cheers!
> >
> >                                         Scott Pickett
> >                                         Philosopher, Projectionist &
> >                                         Apprentice Piano Tech.
> >
> > From: Robert Moffatt Piano Service
> >       Calgary, Alberta, Canada
>
>   -----------------------------------------------------
>
> With all due respect to Hal Lyne, soundboards with that style of rib installation are no less prone to loss of crown than are
> any other. The practice of notching the soundboard liner and insetting the rib to the notch is simply insurance against glue
> failure. That the industry still insists on promoting -- and even featuring -- this practice as gospel has as much to say
> about its worship of tradition as it does about its general lack of understanding about how soundboard systems actually work.
>
> As I've said before, in simplistic terms, the soundboard system functions as a two-dimensional, wave-carrying panel.
> Acoustically, it would be desirable for this panel to have a "hinged" parameter. At least through most of the scale. (An
> argument could be made that the additional stiffness gained by insetting ribs to the liner might be beneficial through the
> treble section -- i.e., approximately the upper third of the scale.) In the bass and tenor sections, however, the practice is
> generally detrimental to the sound of the piano. More than once I've puzzled over the marketing hype that promotes both
> tapered (i.e., "diaphragmed") soundboards and inset ribs at the same time. The two ideas are contradictory.
>
> The practice does, of course, demand good gluing practices. Practices Wurlitzer had only a loose acquaintance with. I once
> purchased an unstrung back assembly from Wurlitzer for some experiments. I got really busy just after receiving it and didn't
> get to it for a couple of years. By then the back assembly was already showing signs of disintegration. Glue joints were
> already failing, and the back hadn't even been strung yet.
>
> -- ddf