Call for scaling spreadsheets

[Frank Emerson]

I probably would not.  Although, I would analyze the existing scale, with
the existing replacement strings.  If I felt I could substantially improve
upon them, I might, but this would probably mean discarding the existing
bass strings entirely.  If I were in the project to make money, I would go
with what I had.  If you are in it for your own edification, by all means,
analyze and modify away.

It wasn't entirely clear if the original scale included wound strings on
the treble bridge, only that there was a replacement set of wound strings. 
To add wound strings where there had previously been plain wire, the treble
bridge would have to be at least partially recapped and repinned, not to
mention relocating and adding hitch pins.  This is approaching a level of
design work that is just not practical for a one-off project.

Frank Emerson
pianoguru at earthlink.net


> [Original Message]
> From: <ed440 at mindspring.com>
> To: Pianotech List <pianotech at ptg.org>
> Date: 9/30/2006 8:54:39 AM
> Subject: Re: Call for scaling spreadsheets
>
> Frank-
> Would you not also consider replacing the lowest plain wire strings with
wound strings?
> If so, how would you go about considering it?
> Ed Sutton
>
> -----Original Message-----
> >From: Frank Emerson <pianoguru at earthlink.net>
> >Sent: Sep 30, 2006 3:05 AM
> >To: Pianotech List <pianotech at ptg.org>
> >Subject: Re: Call for scaling spreadsheets
> >
> >Joe and Ron,
> >
> >I have been following this thread for some time.  As a designer of scales
> >for new pianos, I could offer a VERY lengthy discourse on this subject. 
I
> >do not have time to get into this, and on that scale.  Ron, your
> >contribution seems to me to be the most practical and applicable to the
> >immediate situation.  When one is designing a new piano, with a full
palate
> >of variables at his disposal, many things must be taken into
consideration.
> >On the other hand, when you have the bass strings, and every other
variable
> >is "nailed down," all that you have to determine is the number of strings
> >to replace with each wire gage.  Without control of any other variable,
> >such as speaking length, hitch pin placement, bridge configuration,
bridge
> >pin configuration, bridge design, soundboard design, rib placement and
> >design, etc., all you have to determine is the wire gage to use for each
> >note.
> >
> >Forget about inharmonicity, loudness factor, stiffness, characteristic
> >impedance, longitudinal mode partials, etc, etc.  All of these are valid
> >considerations if you are designing a new scale, but all are irrelevant,
> >and beyond your control, if all you need to know is what gages of wire to
> >use for each note in the plain wire sections.  I have a multi-page
> >spreadsheet for such calculations, but it is an ever evolving thing. 
Each
> >time I use it, I add new calculations.  It would be useless to anyone who
> >is not familiar with its evolutionary development.
> >
> >Count the hitch pins in each plain wire section.  This will tell you a
lot
> >about the original design intent. If there are three hitch pins for every
> >two unisons, this simplifies things.  If there are more hitch pins than
> >this ratio, you have to determine how many strings have to be tied off
and
> >how the side bearing would be influenced.  
> >
> >All you need, in terms of a spreadsheet, is a simple calculation of the
> >tension for each note and a graph to display the tension from note to
note.
> >A reasonable target tension is 160psi.  Ideally you want to minimize the
> >range of fluctuation either side of this target.  Each time you increase
> >the diameter of the wire, you will see a peak in the graph.  This will
> >guide you in determining when and where to change the wire gage.  You
must
> >always have an even number of notes per wire gage, unless you have enough
> >hitch pins to allow tied-off strings to account for this.  The goal is to
> >keep the fluctuation in tension within as narrow a range as possible.  In
> >smaller pianos, it is expected and acceptable to allow a slight upward
> >curve in the tension in the highest few notes of the treble.Get the
tension
> >right in this range, and trust that the original design takes all of the
> >other considerations into account 
> >
> >Frank Emerson
> >pianoguru at earthlink.net
> >
> >
> >> [Original Message]
> >> From: Ron Nossaman <rnossaman at cox.net>
> >> To: Pianotech List <pianotech at ptg.org>
> >> Date: 9/29/2006 3:37:59 PM
> >> Subject: Re: Call for scaling spreadsheets
> >>
> >>
> >> > I guess my question that started this great discussion was really can
> >one
> >> > start with a given ( the bass strings ) and produce a scale that will
> >> > compliment them.
> >> > Joe Goss RPT
> >>
> >> Sure one can, but it won't be all that complimentary because 
> >> that's backward. Without moving bridges and changing speaking 
> >> lengths, about all you can do with plain wire is determine 
> >> tension ranges with wire gage. Inharmonicity will be what you 
> >> get. By far the most control and improvement in rescaling 
> >> happens in the bass, which in this case is already nailed down 
> >> to whatever the existing bass strings give you.
> >> Ron N
> >>
> >
> >
>
>