Article about bridge agraffes - function, types

[Ron Overs]

>At 20:52 +0100 18/11/06, Calin Tantareanu wrote:
>
>>I have uploaded an article on my website about the function and different
>>types of bridge agraffes.
>>This is the direct link:
>>http://calin.haos.ro/c/instruments/bridge_agraffes/index.htm
>>
>>Let me know what you think. I'd also like to know if you have any other
>>pictures & information which I could add to the article.
>
>An interesting article, Calin.  Thank you.

Indeed, thanks Calin for collecting the various versions into one document.

>I have a totally irrational aversion to these frightful things.

You should try to give them some consideration JD. They might prove 
to be a worthwhile tone building asset.

>  I think you might mention the effect the various types have on the 
>tuning stability of the piano.  I have never met a tuner who does 
>not curse the Broadwood bridge agraffes.

Just because the Broadwood version exhibited poor tuning stability, 
it doesn't follow that other bridge agraffe designs will have similar 
problems.

>No matter how shallow these devices they reduce the height of the 
>bridge compared with what it would be without them in a given piano, 
>and bridge height is a most important, and too often neglected, 
>factor in tone-building.

I agree with you here JD. The long-bridge height of the Stuart 
concert piano at the Great Hall, at Sydney University, is 24 mm - 
mmmmmmmmmm . . .

>It might also be mentioned that whatever advantages at the 
>termination of the speaking length Stuart aims to gain, he is 
>enabled by the use of his 3-bearing stud to achieve the "floating 
>soundboard", with no down-bearing, to what advantage I was unable to 
>detect when I met one of his pianos.

Me either -  I strongly suspect that his lack of downbearing (and a 
very low stiffness soundboard panel) is what makes his pianos sound 
the way they do. One of the factors which I believe distinguishes the 
modern piano from the piano of 1870 is the overall stiffness of the 
soundboard panel. 1870 sound boards, with a lower long-bridge height 
and weaker soundboard assembly, have a shorter sustain than most 
modern-day pianos. To my ear, pianos from the 1800's sound like 
a-piano-with-a-cold. While the Stuart isn't as short-toned as one 
might expect from a sound board with such a weak structure, it does 
retain some length which is most likely due to the additional mass of 
the agraffes.

>At the same event he claimed that these things favoured the vertical 
>excursions of the vibrating strings.  No movies were shown to back 
>up this claim.

He would seem to be making claims without looking at the evidence. I 
wouldn't recommend holding your breath waiting for the movie-clip to 
be forthcoming. I held a lamp in close proximity to the strings on a 
Stuart concert grand and watched the initial vertical excursions of 
the vibrating string change to an almost circular patten, as do all 
other vibrating strings on planet earth.

>I am sure others will have interesting experience and views to share 
>on this topic.  So far as I'm concerned these very expensive toys go 
>against the grain of the craftsman.

I think their use should be given serious consideration as long as 
their contribution is musically worthwhile. I also remain unconvinced 
of their merits or otherwise at this time, but I plan to test them 
once I get established as something more than a cottage-industry 
piano maker.

While Stuart claims that the bridge-agraffe is allowing the piano to 
produce longer sustain, it is unlikely to be resulting from the 
superior mechanical characteristics of the agraffe, when compared to 
standard bridge pins. According to Calin's web page, the Stuart 3bp 
agraffes weigh 12.9 grams. The total weight of these bridge agraffes 
will add over 2.5 lbs to the overall bridge mass. I would expect this 
mass to contribute to increased sustain in any piano. Attaching 2.5 
lbs of brass to a conventionally-pinned bridge will also increase 
sustain. In the case of the Stuart, with a long-bridge height of only 
24 mm, there will be approximately 1 lb less rock maple, when 
compared to a standard concert grand bridge of say 34 mm in height. 
So the overall increase in bridge mass on the Stuart concert grand, 
due to the bridge agraffes, will likely be around 1.5 lbs.

Ron O.
-- 
OVERS PIANOS - SYDNEY
    Grand Piano Manufacturers
_______________________

Web http://overspianos.com.au
mailto:ron at overspianos.com.au
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