[pianotech] PR follow up

[David Love]

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.

 

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