RE: Bøsendorfers, was : Buttressed Arch. Question for Ron N. - increasing rim density

[David Love]

Panel characteristics are different between soft and hard rim pianos, it
seems.  The Boes has a much thicker panel than, say, a Steinway.  I would
imagine that is rim driven and the combination certainly drives the
particular tonal characteristics of any given piano.  

David Love
davidlovepianos at comcast.net 

-----Original Message-----
From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf
Of Ric Brekne
Sent: Wednesday, April 19, 2006 12:23 PM
To: pianotech at ptg.org
Subject: Re: Bøsendorfers, was : Buttressed Arch. Question for Ron N. -
increasing rim density

Ed

Well I'm the first to recognize the concept of optimizing efficiency. 
But the whole of what we call a grand piano is in the end a very 
complicated thing as is any idea of just what optimized tone is. Its a 
can of worms as big as any ever opened.  But sticking to just lots of 
power and lots of sustain.... and sticking to the pianos out there that 
are available to compare with, I question whether or not it is possible 
to confirm that the most optimized way to go in this issue is rock hard 
rims. That said... I'll be the first willing to bow to any objectivly 
arrived at data which shows clearly that the total system efficiency can 
be maximized with a hardwood rim vs other system configurations. 

I'm not purporting to <<know>> the facts of the matter ... quite the 
opposite really, my head is itching again :)  Yet it does strike me that 
there are several approaches that all yeild very good results.  And tho 
there are voiced opinions as to tone/sustain/power with respect to rim 
hardness for several piano makes in our mongst, and regardless of how 
high esteem I hold those whome these come from,  I find no confirming 
consensus amoungst the greater world of pianotechs and pianists around 
me and my own experiences are thus far at odds with claims of <<harder 
rims = more power and sustain>>.

Apprapo Andre Segovia.....

Its an interesting question to be sure.  As is the more scopefull 
question of how each piano component might <<best>> contribute to 
optimizing the system impedance matching. 

A question comes to mind about alternative rims... the plexiglass 
rims.... how would you suppose they should perform and does this match 
up with any listening experiences you may have had with them ?  I 
listened to one in Japan last year... but wasnt really thinking along 
these lines at the time.  Sounded like a typical Yamahamahoo really. 
Which is pleasing enough.

As always... I enjoy reading your thoughts immensly Ed.

Cheers
RicB

........................
Ric writes:

<< Another question comes to mind since you site more power.... Power is 
the tradeoff for sustain when talking about impedance issues in  
pianos... yes ? <<

Ed replies:
    I don't know if that is actually a fact.  Resonant systems often
demonstrate an increase in both when the system becomes more efficient.  
     Consider what we could expect from rims made of rubber,  which 
would be
dead everywhere, I think, to a rim made of glass, which would probably be
pretty loud over a small range of notes.  Somewhere in between is a 
material that
possesses the optimum density and elasticity to maximize the energy's
transformation from mechanical to acoustic.   
     The weight of the framing and case, the thickness of the plate, the
thickness of the board, the bearing pressure, back-scale length, etc. 
all combine
to create what is basically a wooden drum. We want it to be evenly 
responsive
to all frequencies from 27.5 Hz to over 10K.   A rim-builder I am not, 
but all
other things being equal, I would expect to see a softer rim material 
absorb
more energy than a denser one.  I don't know that a soft wood rim with 
large
inserts of metal, or whatnot added is going to respond the same way as an
uninterupted laminate of a denser wood.  
    I say that while keeping in mind an anecdote about Andre Segovia.  
He, in
order to prove a point about the guitar's top being the major component of
the sound, had a guitar built with paper mache sides.  It sounded great.   

......................
Regards,
Ed Foote RPT
http://www.uk-piano.org/edfoote/index.html
www.uk-piano.org/edfoote/well_tempered_piano.html