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
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