[pianotech] Downbearing on RC&S designs was RE: Steingraeber

[Joe Goss]

Hi,
 You remind me of a 1896 Hallett and Davis upright grand that had agraffes 
at both temination ends drilled so that every other unison  went / up then 
\ down with the board FLAT.
My first stringing job! Boy was that an education <g>
Tapered tuning pins and very stable, once the strings were seated at their 
termination points.
Had the original pins reblued and used them as the block was good.

Joe Goss BSMusEd MMusEd RPT
imatunr at srvinet.com
www.mothergoosetools.com
----- Original Message ----- 
From: "David Love" <davidlovepianos at comcast.net>
To: <pianotech at ptg.org>
Sent: Sunday, July 11, 2010 9:56 PM
Subject: Re: [pianotech] Downbearing on RC&S designs was RE: Steingraeber


> The interesting thing about downbearing is that in a CC assembly it is a
> requirement for achieving the desired stiffness.  But since the stiffness 
> is
> present in an RC&S assembly by the design itself and downbearing play no
> real role there then I think it's interesting to ask oneself what the
> purpose, then, is of downbearing.  If freedom of movement of the assembly 
> is
> a goal, and if the assembly already has the requisite stiffness, then why 
> do
> we need any downbearing at all?  Why can't the bearing be set neutral?
> Doesn't that give the assembly the greatest freedom of movement?  In the
> pianos where I've had all the design changes made I've found very little
> change in tone with increases or decreases in downbearing.  Where the
> designs have been more conventional (except for the RC&S part--meaning 
> with
> original ribs, original backscale lengths, etc.) then I've found that more
> downbearing can actually be detrimental.  The bottom line is that with an
> RC&S design I think one should rethink downbearing as well.  It doesn't
> serve the same purpose and therefore may work at cross purposes.  I don't
> think that's inconsistent with Ron's findings and I think it is consistent
> with Del's findings.  Since I don't know exactly what Dale's belly 
> structure
> is with respect to where it falls on the continuum of RC&S and compression
> (i.e., are they hybrids and to what degree does compression play a role 
> plus
> how are the rib dimensions calculated etc., etc.) I can't really comment
> there.  I fully respect everyone's right to comment or not to as suits 
> them
> with respect to their own designs, btw.
>
> As far as hammer density my thoughts go something like this.  These 
> designs
> are more hammer sensitive, at least in my experience.  Why is that, I
> wonder?  One thought is that with full bass cut off, lighter and stiffer
> assemblies, increased grain angles, the board's ability to produce higher
> partials through the scale is enhanced.  That can be a problem with a 
> harder
> hammer.  Whereas traditional assemblies might inhibit the development of
> upper partials from the panel itself making them more tolerant of harder
> hammers (and sometimes creating problems in the killer octave as we've
> seen), the RC&S assemblies that have the full soundboard shaping features
> actually encourage the development of upper partials.  The effect of those
> design changes is a better sounding treble, more high partial development
> and better sustain.  That's why a softer hammer produces a brighter tone
> without the need for hardeners.  However it's also why a harder hammer can
> quickly produce too many upper partials, especially in the low tenor and
> bass, making for a somewhat unpleasant sound.  While the bass float
> compensates well for the low bass, it doesn't really help the low tenor. 
> So
> what I've done is not make the bass cutoff too extreme and I've steered 
> away
> from grain angles that are too acute.  So far it seems to improve hammer
> tolerance without having to change the weighting of the assembly itself.
>
> David Love
> www.davidlovepianos.com
>
> -----Original Message-----
> From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On 
> Behalf
> Of jimialeggio
> Sent: Sunday, July 11, 2010 2:45 PM
> To: pianotech at ptg.org
> Subject: Re: [pianotech] Downbearing on RC&S designs was RE: Steingraeber
>
>  Thanks David.
>
> Actually in my opinion, even though we all continue to evolve our
> procedures, the outlines of what you've written, added to your
> observations about grain angle/hammer density etc if complied along with
> other RC&S folks would begin to show tendencies which might confirm,
> challenge, and enlarge each of our private takes on this stuff.
> Compiled knowledge of this sort can get the group think going in ways
> that random queries a on the list and private explorations can't
> achieve...anyway, that's how I see it.
>
> I would ask Ron and Dale to reconsider their opinions on this. Yes its
> here and there on the list, but piecemeal and undirected.  Proprietary
> stuff doesn't need to be part of the mix either in my opinion. WHat will
> happen is one voice will publish info and a wealth of other empirical
> knowledge and experienced opinion will be lost...to our detriment.
>
> My take anyway.
>
> For instance, I still am looking a Davids info, and looking at what
> seems to be a fairly different take on the relative effect of
> downbearing differences
> as compared to Ron's take.  At this point my take(although my experience
> is much less than Ron/Dale/David/Del at this point) is similar to Ron's,
> but I'm always all ears and learning.
>
> If the response to different downbearings that David referred to very
> minor, ie just a 5% tonal difference that David's ear is picking up,
> well that experimental noise. However if the tonal difference is more
> pronounced  I  would want to look further as to why. Stiffness is one
> parameter, but looking at the larger picture of Davids whole system
> might show other trends other than rib stiffness.
>
> David, can I ask if your observations about tonal effect of varied
> downbearing in the very minor or more significant department.
>
> Jim I
>
>
>
>
> -- 
> Jim Ialeggio
> grandpianosolutions.com
> 978- 425-9026
> Shirley, MA
>
>