I would point out that piano requiring pitch correction over 100 cents probably never did achieve great stability after stringing. I've told customers that a newly strung piano will need so much work. You can do it now or string it out over the years and live with more instability and out-of-tune-ness. Either way it will eventually get done. I tuned a piano that was over 300 cents flat and they were quite certain it had never been tuned since it was purchased from a store in 1950. The way this piano behaved, I am quite sure that it was never properly prepped. I did my part and suggested that in 2 months they might want to fine tune it again. Sometimes they call, sometimes they wait and are happy for longer. Andrew Anderson On Aug 28, 2009, at 10:27 PM, David Love wrote: > What else do you think accounts? Soundboard compression? When a > string breaks and the entire section goes out of tune is it the loss > of a few pounds downward pressure on the bridge? If so, then simply > pressing down on the bridge should put the piano noticeably out of > tune. But it doesn’t. Additionally, when you destring the bass on > a piano where the bearing on the bass bridge is pretty much zero, > why does the tenor change so much in pitch? On the other side, a > single string breaking makes a change of over 300 lbs of tension on > the plate. The removal of the bass strings results in a net change > of 7000 -8000 lbs. I would assert that it is primarily (if not > exclusively) the change in the way the plate flexes that is > responsible for the change in pitch. > > The stability after restringing has other issues including the > straightening of the wire at the terminations, the tightening of the > coils, loops and beckets, etc.. This is not really an issue on a > piano that has already achieved that type of stability. The net > loss the comes about during a pitch raise is due primarily to > progressively added contractual tension to the plate. Other factors > that affect stability are the ability for the technician to > stabilize the various string segments as Ron outlined in a previous > post, plus getting to a reasonable starting point from which to > start the fine tuning process. > > David Love > www.davidlovepianos.com > > From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] > On Behalf Of PAULREVENKOJONES at aol.com > Sent: Friday, August 28, 2009 8:00 PM > To: pianotech at ptg.org > Subject: Re: [pianotech] PR follow up > > Some maybe. But you've tuned a piano immediately after stringing, > e.g. and there are all kinds of things happening that affect > stability. A radical pitch alteration, in smaller part, does much > the same thing, don't you think? > > P > > In a message dated 8/28/2009 9:58:14 P.M. Central Daylight Time, davidlovepianos at comcast.net > writes: > What about plate flex. > > David Love > www.davidlovepianos.com > > From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] > On Behalf Of wimblees at aol.com > Sent: Friday, August 28, 2009 6:33 PM > To: pianotech at ptg.org > Subject: Re: [pianotech] PR follow up > > The most general phrases that seems appropriate to start the > discussion would be soundboard (de- and re-)compression over both > bridges, and the string segmentation tension differentials. Seems > enough. :-) > > Cheers, > > Paul > > > Paul > > When I first started tuning 32 years ago, my dad told me that the > reason a piano goes flat after a pitch raise is because strings have > memory and want to "go back where they came from". Then I learned > that the reason a piano goes flat after a pitch raise is because the > soundboard compresses. Then someone told me that the bridge rolls > during a pitch raise. > > But my question are, how much memory does a string have, how long > does it take for the soundboard to compress, and when does the > bridge stop rolling? > > I have done some research on this, and my contention is that old > strings do not have memory, (a new one stretches, but not because of > memory), the soundboard stops compressing and the bridge stops > rolling as soon as the strings have been pulled up to pitch. After > that, it's just matter of stabilizing the tuning, just as you would > during a "normal" tuning. Is this the physics you're talking about? > > Have you done research on this? Have you taken an badly out of tune > piano, lets say 50 cents low, and done a pitch raise and fine tuning > in one setting, then checked it a day later, a week later, a month > later? Providing the environment in which the piano is sitting is > stable, what kind of results did you get? > > I ddi this about 10 years ago, and tracked my results, which showed > the pitch didn't alter. And I just did this on a 50 year old Everret > Studio sitting in my office. When it came in two weeks ago, it was > 45 cents flat. I pitch raised and fine tuned it. I just now played > it, and it's a little sour, but then it's sitting in front of an > open window and partly opened patio door. But in general it sounds > pretty good. > > Wim > > > -----Original Message----- > From: PAULREVENKOJONES at aol.com > To: pianotech at ptg.org > Sent: Fri, Aug 28, 2009 2:01 pm > Subject: Re: [pianotech] PR follow up > > > In a message dated 8/28/2009 6:36:33 P.M. Central Daylight Time, davidlovepianos at comcast.net > writes: > Please explain the physics as you know it that would account for this. > > -------------- next part -------------- An HTML attachment was scrubbed... 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