Soundboard rib question

[David Love]

Does it contact the soundboard panel itself?  What is the actual dimension
of the support and are the ribs the same dimension on either side of it?  I
wonder if it isn't an early attempt at a cut-off that proved to be
ineffective.  Don't the later Bluthners employ a more conventional cut-off?

Of course, it's not surprising that there is a nice bass and lousy treble.
If nothing else, that grain angle makes for a pretty floppy board which
benefits the bass but is fairly useless in the treble.  Hard to imagine how
anything you might do staying with the original set up will help the treble
much.

David Love
davidlovepianos@comcast.net 

-----Original Message-----
From: pianotech-bounces@ptg.org [mailto:pianotech-bounces@ptg.org] On Behalf
Of Ric Brekne
Sent: Sunday, January 22, 2006 1:43 PM
To: pianotech
Subject: Soundboard rib question

Hi David

I guessed that the long massive bar in slides 9 and 10 was a kind of 
crown support.  It goes roughly down the middle of the soundboard semi 
parallel to the tenor portion of the long bridge. It does not contact 
the beams or bracings no. The picture perhaps give that impression 
especially at the tail.. but it does not.   The grain does go roughly 
perpendicular to the bridge yes.

Yes... its an interesting dilemma.  It sounded suprisingly ok before 
string down... particularilly in the bass.  Tho it was a bit hallow and 
thin in the treble and not much sustain.

Btw... for those speculating about how much compression and crown (if 
any) there was in the board. The cracks farthest bass side showed every 
sign of being compression ridge in origion. A straight edge placed on 
top showed that the wood adjacent to the cracks were high points... 
ridge like.  I dont see really how some crown could be avoided given the 
cross grain orientation of the ribs. If they didnt dry out the board 
enough to result in some crown.. the thing would have just pulled apart 
in the winters... yes ??

Cheers
RicB

------------
Pretty interesting and unusual by today's standards.  The grain appears to
be perpendicular to the bridge--do I see that right?  Slide 9 and 10 appear
to show a massive bass cutoff bar--is it attached to the bracing?  It
appears to be.  At what point did Bluthner change the grain angle to be more
parallel with the bridge?  An interesting dilemma if you want to remain true
to the original design yet produce something which will perform well.  What
did it sound like before you took it apart?  I think Andre's analogy is a
good one.  

David Love
davidlovepianos@comcast.net


Hi folks

Below are links to several pics of the Bluthner... including a couple of
the underside. I will get better shots of that when I remove the panel
but these will suffice for now me thinks.

Cheers
RicB

http://www.pianostemmer.no/pics/slide9.jpg
http://www.pianostemmer.no/pics/slide10.jpg
http://www.pianostemmer.no/pics/slide11.jpg
http://www.pianostemmer.no/pics/slide12.jpg
http://www.pianostemmer.no/pics/slide13.jpg
http://www.pianostemmer.no/pics/slide14.jpg
http://www.pianostemmer.no/pics/slide15.jpg
http://www.pianostemmer.no/pics/slide16.jpg
http://www.pianostemmer.no/pics/slide17.jpg
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