[pianotech] Steinway A Bass String Rescaling

[William Truitt]

Hi David:

Thank you very much for this contribution.  I think this is the most cogent
and inclusive explanation of what is involved in rescaling thus presented;
and I doubt you will find much disagreement amongst the contributors to this
thread.  

I think we have good scaling when nothing stands out as bad, nothing
offends, or brings attention to itself.  Of course, how fully we can achieve
that is tempered by the limitations of size imposed by a given piano and the
cleverness of the designer.

All this talk about inharmonicity in rescaling should not come as too much
of a surprise; we are, after all, piano tuners who butter our bread dealing
with inharmonicity in pianos every day.  

There are other circumstances where tension differences are audible.  I
rescaled an old Weber grand years ago.  There was a serious dog leg at one
of the breaks in the treble, and a resulting difference in tension of almost
30 lbs. Did the notes on each side of the break sound different?  Oh, yeah.
Changing wire sizes made it mildly less offensive, what would really have
been required would have been to change speaking lengths also.

Will



-----Original Message-----
From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf
Of David Love
Sent: Sunday, May 24, 2009 11:33 AM
To: pianotech at ptg.org
Subject: Re: [pianotech] Steinway A Bass String Rescaling

Since different pianos have a tendency toward a particular scale
design--high, medium, low tension--the absolute inharmonicity values will be
a function of that particular scale.  Other than transitional modifications,
you probably don't want to deviate a lot from the original intent of the
pianos design in this respect (there are exceptions--take original Knabe
scales for example).  In other words, it's not best to convert a Steinway
(low tension) to a high tension scale for reasons relating to general tonal
character, soundboard deflection designs and plate capacity to take
additional tension.  Thus, the absolute inharmonicity values for the plain
wire section will be somewhat given. Any changes there will likely be very
minor and will pay attention to other factors.  

Moving through the low treble and into the bass you will want to tie all the
factors together for a smooth transition as much as possible: tension,
inharmonicity, Z, and to a lesser degree BP%.  Between each section, plain
wire to bichords, and bichords to monochords, there will be some jumps and
you have to choose which of those factors is more important in terms of how
this will all sound which forces you to consider which factors you actually
hear when you are able to compare them butted up against another section
where there is some type of transition.  As Ron and others have mentioned,
you don't really hear absolute inharmonicity values.  Problems with
inharmonicity become evident only in tuning adjacent but different sections.
Different scale designers choose to emphasize different factors in their
decision making process especially when working with original bridge layouts
that require more and greater compromises than were you to lay out a new
bridge or modify the existing one with added transitions, changing
bi-chord/monochord transition point, etc.  For example, you can hear tension
changes as evidenced when you listen to the bottom end of the plain wire
section of a Steinway B comparing it with notes a little farther up the
scale.  You also hear tension and Z factor differences when, again, you
compare the bottom end of the Steinway B long bridge against the notes at
the top of the bass bridge (soundboard response differences
notwithstanding).  While those differences also influence the inharmonicity
between those two sections, you don't really hear that as a qualitative
difference.  

Emphasizing inharmonicity at the expense of other factors is probably a
mistake in terms of how well the piano blends and balances.  

David Love
www.davidlovepianos.com

-----Original Message-----
From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf
Of William Truitt
Sent: Saturday, May 23, 2009 4:17 PM
To: pianotech at ptg.org
Subject: Re: [pianotech] Steinway A Bass String Rescaling

"we don't hear the inharmonicity in pianos. ... too much emphasis is still
being put on absolute inharmonicity values in scaling."  So Ron, this meants
then, that you would favor a scale with no inharmonicity, right?  (I KNOW
that I'm being bad, but I can't help myself...)

Will