Short Treble (sustain?)

[Overs Pianos]

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Del, Ron N. and all,

The string buzzing on the side of the agraffe slot is most certainly 
the problem. Earlier in my career I recapped the failed bridges on a 
Grotrian 220. Since the owner was travelling to Germany on business, 
when he visited the factory they sold him a replacement treble bridge 
cap. Unfortunately, the new bridge cap was afflicted with the same 
'disease' which was common to '70s era Grotrians (I have no idea if 
it remains a problem with their contemporary instruments). However, 
the bridge pin spacing was so close that there was virtually no free 
space between the string and the adjacent bridge pin. Consequently, 
there remain several notes on my client's Grotrian 220 which have 
string noise at the bridge pins (which varies in intensity according 
to the relative humidity at the time). A gentle side pressure on an 
offending bridge pin will stop the noise.

These Grotrian bridges from the '70s are prone to failure on account 
of the close bridge pin spacing. There is simply insufficient bridge 
wood around the pins to provide adequate support for the side thrust 
on the pins. On Grotrians from earlier periods they have used a wider 
bridge pin spacing and they do not have the same problem. Isn't it 
amazing how corporate knowledge often fails to be passed down from 
one generation to another? The 'Johnny come latelys' turn up with new 
thinking but fail give appropriate consideration to lessons learned 
long ago by an older generation of thinkers. I'm all for innovative 
technologies, but one should come to it after stepping off from the 
knowledge which has gone before.

Clearly, the idea of placing a damping material on a noisy string 
segment (wether it be new-age silicon as in the case of the Stuart 
agraffe, a piece of felt or a lump of fat from under the barbecue), 
its still is just a case of fixing the symptom instead of addressing 
the cause of the disease.

The bridge agraffe we have been discussing is a case in point. It 
simply wasn't thought through prior to execution. I concur with your 
views Ron N. and Del, with regard to widening the slots and using 
rolled pins as a solution. Less overall height would be a plus as 
well. As you and I have both mentioned previously Ron N., it would 
allow for the retention of a more sensible bridge height and 
stiffness.

Ron O.

>----- Original Message -----
>From: "Ron Nossaman" <RNossaman@cox.net>
>To: "Pianotech" <pianotech@ptg.org>
>Sent: November 01, 2003 8:23 PM
>Subject: Re: Short Treble (sustain?)
>
>I suspect the problem is with the string buzzing against the side of the
>slot.
>
>Del
>
>  Perhaps, though I have a hard time imagining much vibration excursion in
>  that short segment. At that, how difficult or more expensive is a wider
>  slot, as long as you're cutting one anyway? It's not like it will cost
>  anything important in rigidity. A grooved center rod would help too,
>though
>  it would cost a bit more to produce.
>
>  Ron N
>
>-------------
>
>As do I. I did think it a possibility, though, as I worked with similar
>devices at Baldwin. The easiest way to solve the problem (if it exists)
>(and, other than putting some damping material between the leading
>termination and the center deflector rod) is, as you suggest, to groove the
>center rod. This could be rolled and, in quantity, is not as expensive as
>you might think. In limited quantities, however, it might well be a factor.
>This can be used to solve another problem as well -- the varying string
>deflection angles as the wire size changes. I played around with several
>groove depths, deeper in the low tenor and bass, more shallow in the
>tenor/treble.
>
>Del

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