an analysis of downbearing, etc.

[Phillip Ford]

>Phil-
>I will try to find the information you mentioned.  Any idea as to 
>the thread titles?

I'd try something like 'reverse crown'.

>  In the mean time, maybe I'm really suffering from something, but 
>what is being said here?

All I think I've really said is that a reverse crown board won't 
necessarily self destruct as some people seem to imagine.

>   That there is no particular need for crown and downbearing?

I think that's a good question.  And it's a question that I've asked 
before and was asking recently in some posts of a couple of weeks 
ago.  The explanation usually seems to be that they 'raise the 
impedance of the board'.  One explanation offered is that the 
downbearing is supposed to be making the board 'stiffer' without 
adding to its mass.  Another explanation is that the string plane 
loading is impeding board movement, thus making it 'stiffer' in a 
sense.  Both of these may be true, or neither may be true.  I've seen 
no convincing evidence either way.  And there won't be any without 
some experimentation and data collection, which has not been done, or 
the data not made public, to my knowledge.  Experience would seem to 
indicate that in most cases (but seemingly not all), crown and 
downbearing will result in a better sounding piano.  But I have no 
explanations to offer at the moment as to why that is.

Another related question is, if crown and downbearing are needed on a 
board of normal design, would they be needed on a board that was 
designed based on what you learned from the experiments mentioned 
above?



>   That the board impedance that was talked about very recently will 
>exist whether the board is being compressed or tensioned?

I assume so, but I don't know.

>  Positive, negative bearing...it's all the same?
>
>David Skolnik

I don't know about that.  For one thing, it probably depends on 
whether you're pairing said bearing with a positive crown or negative 
crown board.

I don't really have any experience with reverse crown boards (at 
least any that were designed to be that way), so I don't know if they 
sound the same or behave the same as positive crown boards.  Maybe 
saying they're the same would be inappropriate.  Maybe saying that 
they both give pleasing results would be appropriate.  I don't really 
know.  I'll have to wait until I hear one.

Phil Ford