Call for scaling spreadsheets

[ed440 at mindspring.com]

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
>>
>
>