Soundboard Thoughts

[Delwin D Fandrich]

Ron Nossaman wrote:

> Hi Newton,
>
> It would split twice as fast? If it were taller than it was wide, would it
> "break off" with a major pitch raise? How about "flagpoling bridge syndrome"?
>
> The splitting part brings me to something I wanted to ask anyway. Is there a
> reasonable body of empirical evidence that horizontally laminated bridges
> are evil, or is it just that since they are found on evil pianos, it's
> assumed? Have horizontally laminated bridges been actually installed in
> decent pianos and tested?
>
> Ever a "lert" and in anticipation, Ron
>
> Ron Nossaman

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The idea that horizontally laminated bridges were a bad thing is a holdover from the days when folks were concerned about the
speed of sound through the glue joint. The idea was that if it was different from that if the wood it would somehow upset the
sound wave.

Piano bridges are just that -- bridges. They have mass and they have stiffness. There are a variety of ways to design and
build good bridges and just as many ways to design and build bad bridges. Horizontally laminated bridges can be designed to
work just as well as either solid body bridges or vertically laminated bridges. Mostly it's a matter of what the manufacturer
is tooled up to make. If you are making more than just a few pianos, vertically laminated bridges are easy to make. All it
requires is a simple press and a male and female caul. If you have CNC milling machinery, then horizontally laminated bridges
are easy to make.

My personal preference is a vertically laminated body and a horizontally laminated cap. This combines the ease of manufacture
of the vertically laminated body and the excellent termination qualities and durability of the horizontally laminated cap.

Solid body bridges are pretty much a thing of the past for most practical purposes. Not only is good material is too hard to
come by these days, but it's not a good idea to bond laminated stock to solid stock. The expansion and contraction rates are
quite different, hence the often seen delaminated bridge caps.

-- ddf