String noises revisited

[paulrevenkojones at aol.com]

 Bob:

The process is time-consuming, and as far as we are concerned from a tonal point of view (yet to be proved) we are quite pleased. David Carpenter and I are putting together the experimental structure to detect whatever differences we can.


"Crystallization"? Alpha-brass as a stable alloy doesn't crystallize as far as I know. Or am I misunderstanding you?

Paul

 

-----Original Message-----
From: BobDavis88 at aol.com
To: pianotech at ptg.org
Sent: Thu, 10 Jul 2008 10:32 am
Subject: Re: String noises revisited














Paul,


?


I almost mentioned your reshaping/polishing process [published in the PTJ]. 
The last couple sets of agraffes we got from Pianotek had such a nice shape 
inside that we put them in as they were. Maybe we were just lucky.


?


What kind of time does your process take? With agraffes at about a buck, it 
seems like it would have to be a minute apiece or less to be break-even, IF we 
can get good new ones; and the new ones would not have any risk of 
crystallization.


?


Bob Davis


?




In a message dated 7/10/2008 12:16:24 A.M. Pacific Daylight Time, 
paulrevenkojones at aol.com writes:



  
Bob:

Why replace them. 
  The inside profile of all agraffes, including new ones, is a "mesa" shaped 
  termination which needs to be reshaped into a proper curved profile. The old 
  agraffes are still good; why pay for new ones that need the same 
  treatment?

By the way, we are currently beginning an experimental 
  process to (no pun intended) determine the tonal differences (more or less 
  transient noise like this shimmer) between flat inner profile and curved inner 
  profile agraffes. I'll let you know. 

Paul


  



  


-----Original Message-----
From: BobDavis88 at aol.com
To: 
  pianotech at ptg.org
Sent: Thu, 10 Jul 2008 12:33 am
Subject: String noises 
  revisited


  

  
?

  
?

  
Allen Wright writes:

  
Has anyone 
    working on Hamburg Steinway B's (or similar instruments)? 
    
encountered shimmery high partial noises (quite noticeable) at the? 
    
level of 4 octaves up (perhaps at the major seventh pitch or? 
    
thereabouts), in the area around E3 in the plain wire tenors? 
    Perhaps? 
half dozen notes stand out like this....

  
Allen, I'm still thinking about this, and, although I don't know if it 
  relates to the Hamburg pianos, there was a run of New York pianos in the 
  seventies that had a poor agraffe profile. That is to say, the shape of the 
  inside of the agraffe did not make a good termination. I have a couple of D's 
  that exhibit this in the tenor. We restrung one,?changing the agraffes, 
  and it really cleared up the high metallic whistle. Inspecting the old and new 
  agraffes under magnification really showed up the difference.

  
?

  
On the other D,?increasing the draft angle slightly by putting a 
  center pin under the string (on the counterbearing felt) made a big 
  improvement, although we'll still eventually want to replace the 
  agraffes.

  
?

  
Let us know when you find out for sure what it is.

  
?

  
Bob Davis




  

  


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