out of tune Wurlitzer

[Delwin D Fandrich]

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

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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