String termination question

[David Love]

Are you asking why there aren't pins at the capo bar (or agraffe)?  Part of
the reason there are pins in the bridge is to keep the strings from moving
sideways.  The relatively low bearing on the bridge (as compared with the
counterbearing angle for the agraffes or capo bar) combined with the bridge
surface's natural lubricity would allow the strings to move side to side
quite easily especially as the bridge moves up and down.  You don't want
that.  You might note, however, that on guitars and other stringed
instruments, the strings are not locked into place with vertical pins at the
bridge and they don't seem to move.  Anyway, the same problem doesn't exist
at the capo or agraffe though leakage can occur where counterbearing angles
are insufficient.  

 

Changing lengths, btw, will not necessarily cause an increase in
Inharmonicity, rather a difference between similar strings.  Also, bass
string do exhibit a tolerance for different speaking lengths (and different
winding lengths) without causing problems with Inharmonicity as evidenced by
the number of pianos in which the bass bridge is not individually notched
for each set of unisons.  

 

Of course, I'm not sure if that's what you are talking about.

 

David Love
davidlovepianos at comcast.net
www.davidlovepianos.com 

-----Original Message-----
From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf
Of Geoff Sykes
Sent: Sunday, January 13, 2008 8:05 PM
To: 'Pianotech List'
Subject: RE: String termination question

 

Wim --

 

BUT... As I understand it, one of the important reasons for the X and Y axis
to terminate at exactly the same point, (at the bridge), is that if one axis
is different than the other then the string is essentially a different
length in one axis than the other. This increases inharmonicity and causes
conflicting partials in the two axis. This is a similar reason as to why the
windings on bass strings must be the same length and end at the same
distance from BOTH termination points. I understand that, among other
things, equal termination at the bridge equates to maximum transfer of
energy to the soundboard, but doesn't unequal termination at the agraffe or
capo bar cause distortion in the string waveform that not only increases
inharmonicity and unwanted conflicting partials but also a loss in overall
energy?

 

I don't mean to start an argument. I'm really just interested in the
mechanical logic of this centuries old manufacturing practice. For all I
know the contribution of any errors at the agraffe or capo bar may be so
insignificant as to be unworthy of consideration. I'm just curious. 

 

-- Geoff Sykes, Los Angeles

 

 

 

 

-----Original Message-----
From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf
Of Willem Blees
Sent: Sunday, January 13, 2008 7:22 PM
To: pianotech at ptg.org
Subject: Re: String termination question

Geoff

 

As Annie indicated, the string needs to go over the bridge for the
vibrations to transfer from the string to the soundboard. The string needs
to be seated at both sides of the bridge, so that the vibration is
transferred without interference. If the string is not seated, then there
will not be a solid transfer of the vibrating string. 

See what happens when you start thinking.  :
<http://o.aolcdn.com/cdn.webmail.aol.com/33706/aol/en-us/images/aimex/cry.gi
f> 

Willem (Wim) Blees, RPT
Piano Tuner/Technician
Honolulu, HI
Author of 
The Business of Piano Tuning
available from Potter Press
www.pianotuning.com



-----Original Message-----
From: Geoff Sykes <thetuner at ivories52.com>
To: Pianotech at Ptg. Org <pianotech at ptg.org>
Sent: Sun, 13 Jan 2008 3:42 pm
Subject: String termination question

Greetings All --

 

I made the mistake of thinking the other day, and I started wondering why
piano strings are terminated at the bridge on both the X and Y axis but at
the capo bar, or agraffe, on only the X, (or perhaps that's Y depending on
how you are looking at it), axis. We go to lengths to make sure the strings
are seated properly at the bridge so that there is a definite and precise
termination in both planes at the bridge and bridge pin. Why then is the
lack of termination in both planes not a problem at the agraffe and capo bar
end? 

 

-- Geoff Sykes, Los Angeles


  _____  


More new features than ever. Check out the new AOL Mail
<http://o.aolcdn.com/cdn.webmail.aol.com/mailtour/aol/en-us/text.htm?ncid=ao
lcmp00050000000003> !

-------------- next part --------------
An HTML attachment was scrubbed...
URL: https://www.moypiano.com/ptg/pianotech.php/attachments/20080113/470e8e90/attachment-0001.html