MPR / mPR

[Carl Root]

Good Morning All,

It's unfortunate that we don't have two different words to distinguish a
'M'ajor pitch raise from a 'm'inor pitch raise.  The purpose and
techniques are quite different.

Where we draw the line between the two is not really important.  If a
piano is more than a quarter step flat (more or less, depending on the
piano, your technique, experience, etc.) your goal is to prepare the
piano for a minor pitch raise (or 'rough tuning', if you prefer).  Think
of your goal as prestressing the plate - getting the structure up to
full tension - rather than getting each individual string close to its'
final pitch.  

A stable pitch reference is much more helpful than working off a
temperament which will drop dramatically as you increase the load on the
piano.  I bought an Accu-fork for the purpose, now use an RCT, and can't
imagine changing pitch without some sort of unchanging reference.

A Major pitch raise is all about speed, rhythm, and a consistent hammer
technique which will get you in the ballpark even if you can't hear
every string change.  Mutes are not necessary at this stage.  They only
slow you down. You can easily do this within ten to fifteen minutes,
five if you're trying to break records. 

(Consider testing a couple strings in each section to determine the
possibility of string breakage.  You may choose to abandon the piano,
especially if there are other action related problems.) 

A minor pitch raise prepares you for a fine tuning.  If the overall
pitch level from your Major pitch raise is still below pitch, than you
should attempt a calculated overshoot as part of your usual tuning.  Use
mutes, strips, set a temperament and try to get within 1 bps for unisons
and octaves, maybe closer depending on how far off the piano was to
begin with.  This should not be a long, drawn out process either - a
half hour, 45 minutes tops.

There seems to be a major divergence of opinion on how well a subsequent
fine tuning will hold up at this stage.  Some say that structure and
string segment changes are significant and that a high level tuning will
not last very long - if indeed it can be accomplished at all.  Others
say once you've put everything back in balance, it will stay there, just
as if it had been there all along.  My approach is that a concert level
tuning is seldom expected after years of neglect.  I'm much more
interested in getting the piano on a regular service schedule and
dealing with other aspects of the piano's performance - regulation,
voicing, etc.. The fine tuning could be in a couple of weeks or even
months.  It depends . . . . .  

It seems to me that unlike some of our other theoretical discussions,
the issue of short term tuning stabily following a Major pitch raise
could be resolved with a controled experiment.  Maybe it's already been
done.  I'd sure like to see the data if it has.  Most of us deal with
this issue on a weekly, if not daily, basis. 

Carl Root, RPT
Rockville, MD