downbearing direction

[Stéphane Collin]

Hi Terry.

In my opinion, the best way to know if hitting the string with the hammer in the direction opposite to that of the bearing of the strings on the bridge has a non negligible effect that would be different from the situation the other way round is to make extensive study with closely controlled trials and well criticised measurements.
The other way, far easier and cheaper (and also subject to ridiculous errors as well), is to guess with our mental formalizing of the physics involved in the process.

My try (worth no more than my present formalizing of piano physics, subject to change without notice) :

I'd say that as the hammer strikes the string at the side of it's speaking length opposite to the bridge, the bridge will mainly experiment the force of the wave movement of the string, which in one case and the other will only differ by this : 180° in the directions of the first impulse.  After the first reflection, both cases seem quite equal to me.  And my guess is : too little the difference to be of some importance.  Maybe in the high trebble, where the speaking length is short, and thus the relative stiffness of the strings (relative to the length) could lend me to think that maybe in the case that the hammer would strike in the direction opposite of the downbearing, you could notice an increase in cases where the string lifts up from the bridge and doesn't make any good contact anymore with the bridge.  But when I think that this occurs anyway, even (maybe more often) in low trebble and tenor strings, then I guess that the lift from bridge effect is due more to the global vibration of the string than to only the first transitory shock wave of the string.  Maybe, both cases could differ by a slight alteration of the thump.

But more important than this, I beleave, while I admitt it is very useful to build the best formalization possible to help understand the piano, that any formalization up to now is still FAR away from the reality, and that so many tangible exceptions to any rule I know better lead me to humble attitude and true contemplation of the unknowable but directly feelable beauty of a well sounding instrument.  (Ok, I admit : I don't know much.)

Regards,

Stéphane Collin.


----- Original Message ----- 
From: "pianolover 88" <pianolover88@hotmail.com>
To: <pianotech@ptg.org>
Sent: Tuesday, December 23, 2003 6:31 PM
Subject: downbearing direction


| I don't know if this has ever been brought up on the list, or elsewhere, but 
| because of my hyper-curiosity, here goes.
| Another difference between verts and grands (that has not been addressed, as 
| far as i know)is that the upright hammer travels in the same direction as 
| downbearing, whereas the hammers of the grand action impact the strings in 
| the opposite direction; AGAINST downbearing. I'm wondering if this MIGHT 
| have an effect, if any, on the strings where they seat on the bridges. If 
| so, it would seem logical that the upright strings would stay seated better 
| than grands because of the positive direction of impact. Probably no 
| appreciable effect, but I thought it was an interesting observation anyway.
| 
| Terry Peterson
| 
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