Temperature Change affecting pitch

[Larry J Messerly]

My conclusion from my poorly designed study is that it is important to
watch out for drafts (probably sun also) when tuning.  The change in the
string seems to be quite rapid and is only ameliorated when the plate and
frame catch up.

I am uncertain if humidity or temperature changes cause individual
unisons to go out. Larry

On Mon, 27 Mar 2000 09:54:15 PST "Charly Tuner"
<charly_tuner@hotmail.com> writes:
> I assume even a minor drop/rise in pitch, due to humidity changes 
> will make 
> perfect unisons go out randomly, so it will be out of tune the next 
> day. 
> This is the problem I have at the store where I work...NO hunidity 
> control, 
> big picture windows allowing sunlight/heat to focus DIRECTLY on 
> SB's! So I 
> have a real dilemma trying to keep these pianos, the vast majority 
> of them 
> new, in tune from one day to the next..and of course the store pays 
> me to 
> tune them/PR them, basically once.
> 
> I was in Beverly Hills this past Sat, and I encountered a 
> magnificent 
> Bosendorfer Imperial 9ft. Concert Grand. I was there to have my 
> original 
> piano compositions performed by Maria Demina, a remarkable concert 
> Pianist 
> and good friend. I also had the session recorded by a sound engineer 
> from 
> KKGO FM, the Los Angeles Classical Radio Station. He recorded in 
> "DAT" and 
> later this week I will get a CD of the final edited performance, so 
> I am 
> pretty excited about that! I was told by  the owner that the piano 
> had just 
> been tuned only 3 weeks ago, but I found a great many unisons were 
> quite 
> out, so luckily I had brought my tuning tools, so i was able to do a 
> quick 
> touch-up tuning and all went well.
> 
> Terry
> 
> TErry
> 
> >From: Larry J Messerly <prescottpiano@juno.com>
> >Reply-To: pianotech@ptg.org
> >To: pianotech@ptg.org
> >Subject: Re: Temperature Change affecting pitch
> >Date: Mon, 27 Mar 2000 06:25:17 -0800
> >
> >Well Ron,
> >It is dry here.  relative humidity went from 28 to 26% on a Radio 
> Shack
> >gauge.  Checking this morning total pitch drop is 0.2 and 0.3 
> cents.  So
> >it seems like the immediate affect of temperature change is 
> mitigated by
> >time as the whole structure equalizes temperature.
> >Larry
> >
> >On Mon, 27 Mar 2000 06:29:26 -0500 Ron Torrella
> ><rontorrella@worldspy.net> writes:
> > > What was the relative humidity at 61 degrees? What was it when 
> you
> > > figured
> > > the pianos' pitch had stabilized? Raising the room temperature
> > > probably
> > > lowered the rh and I'll bet that's what caused the pitch change.
> > >
> > > Ron Torrella, RPT
> > > Ypsi, MI
> > >
> > > Larry J Messerly wrote:
> > >
> > > > Just for my own information, when I came into my store this
> > > morning I
> > > > took pitch readings on two grands at 61degrees F. then turned 
> on
> > > the
> > > > heating system and raised the temperature to 68 degrees.
> > > >
> > > > The 6' Kranich and Bach dropped pitch 3.2 cents initially and 
> then
> > > when
> > > > (I presume) the plate temperature rose, ended up 1.6 cents 
> flat of
> > > where
> > > > it had begun the morning.
> > > >
> > > > The 5'3" George Steck initially dropped 0.4 cents then 
> continued
> > > to fall
> > > > to 1.2 cents from where it had been.
> > > >
> > > > They have not changed any more over the last hour.
> > > >
> > > > No real problem or question here, just thought it was 
> interesting.
> > > >
> > > > Larry Messerly, RPT
> > > > Phoenix/Prescott
> > >
> >
> >Larry Messerly, RPT
> >Phoenix/Prescott
> 
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Larry Messerly, RPT
Phoenix/Prescott