string "noises"

[Ed Sutton]

Allen-

Sounds like a perfect description of a longitudinal mode.

Pitch locks are an interesting suggestion. They're cheap and won't hurt anything. And it would be a great discovery if they stop the longitudinal wave.

For longitudinal mode sounds, Jim Ellis' book does not recommend changing the string gauge. He suggests (without a lot of enthusiasm) softening the hammer enough to reduce the energy in the higher partials. He also says you can try moving the strike point in some circumstances. You could try sliding the action out a bit to see if it makes a difference, and if you are very lucky, rehang the hammers.

Ed Sutton
  ----- Original Message ----- 
  From: piano57 at comcast.net 
  To: Pianotech List 
  Sent: Friday, July 04, 2008 6:11 PM
  Subject: Re: string "noises"


  Hi Allen,

  Do you have any Pitch-locks to try out?

  Barbara Richmond, RPT




    -------------- Original message -------------- 
    From: Allen Wright <akwright at btopenworld.com> 
    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. I notice that the sound greatly diminishes when I detune the notes by a semitone or so...is this the longitudinal mode behaviour I've read about in previous threads? 


    And if so, are there specific recommendations for changing wire gauge there in order to eliminate or improve this problem? I'd love to try something like that - this is a piano belonging to a customer who's really bothered by the sound. Personally, if it were my piano I think I'd ignore it and probably not be bothered by it much in a musical context; but you all know how these things go - that sort of suggestion often doesn't fly with the concerned customer.


    Any opinions/suggestions will be most welcome. I've been able to otherwise even out the voicing nicely, with some lacquer in the bass and judicious shaping and needling elsewhere, which leads me to be optimistic that if I can minimize this "feature" the customer may ultimately be quite happy with the piano again. The piano is in the shop, which means I can go at it methodically and even experimentally.


    Sincerely,


    Allen Wright, RPT
    London, UK










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