[pianotech] pitch and temperature

[Encore Pianos]

It has to be the strings.  Case in point:  I tune a small Yamaha grand for a
church house in in an old New England Congregational style church.  Built in
the early 1800's, big rattly windows, and no insulation.  They stopped
heating the church between Sunday services a couple of years ago.  When I
would come to tune the piano in January or so, they would jack the
temperature up from 10 or 20 degrees to 70 an hour or so before I would
come.  The church air is 70 when I get there, but the piano is so cold that
frost is forming on the sides from the condensation (no joke!!)  I would
spend the whole wasted two hours and 3 passes before I gave up chasing the
pitch all over the place.  As the piano strings would warm up, the pitch
would change so rapidly that by the time I got to the ends of the piano, the
middle would be out again.  The rest of the piano is a thermal mass that
takes much longer to warm up than the strings - I would have to guess many
hours to achieve equilibrium with the air temperature and that of the
strings - I certainly would give up long before that time.

Will Truitt 

-----Original Message-----
From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf
Of Ron Nossaman
Sent: Monday, January 10, 2011 10:29 AM
To: pianotech at ptg.org
Subject: Re: [pianotech] pitch and temperature

On 1/10/2011 3:14 AM, Tony Caught wrote:

Hi Tony,
> Now you say that the strings change 1/2 way through the tuning. The 
> question is is this caused by the soundboard expanding or shrinking or 
> the strings expanding or shrinking.

It's definitely the strings. A few degrees difference will produce a
measurable pitch change very quickly. MC change in wood resulting from that
small temperature change will take hours-to-days.


> Or, my head just shrinking so the sound is expanding.

"As the circle of light increases, so does the circumference of darkness
around it".
--- Albert Einstein ---


Ron N