By entering some basic construction limits such as:  the number of strings, the lengths of first and last strings, string angle to soundboard, string spacing, and pitch range, HyperHarp builds a basic shape based on a parabolic curve.

Once the basic geometry is created, the shape of the neck can be modified in regard to symmetry, tightness of sweep, rounding of the pillar and aft ends of the neck, and distance between bridge pins and tuning pins.  The Angle of strings to soundboard can also be adjusted for immediate affect on the design aesthetics.

In the end, some pleasing shapes can result.  Once a shape is selected, HyperHarp filters through any and all plain and wound strings that are selected from a list of sizes and materials.  The list is infinitely  editable, but I currently have Nylon, Gut, Steel, Brass, Phospher Bronze, Copper, and Carbon Fiber "loaded" into the pool of choices.(e.g., Strings and Wire , Olin Brass Wire Alloy Guide )  I have fiber and silk loaded as padding.  HyperHarp can "wrap" any combination of string gauges and materials.

After stringing, a "string picker" displays all possible choices for each string based on the materials and sizes selected.  A "filter" system can be adjusted such to allow only those string that meets certain limits are choosen (i.e., maximum tension, % of tensile strength, T/L ratios, and several other oddball values I have created to assist in final selection of strings).

By pointing and clicking on desired string diameters sorted by ascending values of tension, a final set of strings can be selected, reloaded into the the main program and re-run such to build a coordinate system that spaces strings to a tolerance of 1000th of an inch.

What is more, the coordinate system can be loaded into any graphing program capable of "x-y paired" charting and full sized blueprints of the design can be printed (I use  DeltaGraph ), but I think Excel and some other spreadsheets can do the same thing.  The result can be pasted to template-board and cut to final desired nominal shape.

The values for the harp links above can be pasted into a spreadsheet and will make a basic harp plan.  You will need to cut /paste the indiviudal columns of data or save as TEXT (.txt) and clean it with a word processor.  I will be adding an FTP download system someday (as soon as I figure that crazy stuff all out).

I will create a harp for a nominal fee which we can negotiate.  I've been doing it free to date, but time is becoming a comodity for me that I can only trade for some cash or barter of your choice.

Use the submit form to send me your general design considerations.

HyperHarp can also analyze existing harps. In order to do this, the string lengths and the top note are all that need be known.  From the result, the "string picker" and filters can be engaged and a final arrangement can be selected, but it must be understood that for an existing harp any string changes from orignal builder specs may affect string-spacing and tone a wee tad.

If you'd like me to analyze your harp, I will gladly do so for $25 which I will accept on an honor system.  You submit the following information:

1)  Your highest note (or for re-stringing, the highest note you want to switch to);

2)  Any accidentals you want your harp tuned to with all levers disengaged;

3)  Your string lengths in a single column starting with the shortest string;

4)  Your desired string materials;

5)  A general range of tension (high, medium, soft or overall pounds tension)...

...and I will e-mail back to you a couple of possible arrangements.  After you review them, you can slip a check into snail mail so that I can buy my border collie, Sparky, a new frisbee and a couple of bones.  I'll try the honor system for a start.  If I don't get too burned, I'll continue that method.
 

String codes and materials

Item 1 = code (for program recognition), 
Item 2 = material name, 
Item 3 = mass #/in^3, 
Item 4 = tensile strength, 
Item 5 = mass Kg/M^3, 
( ) = where I obtained the values.

Gt ,Gut,.0432598,44000,1200 (American Institue of Physics)
Ty Ny Mo ,Nylon, .0.038467, 56000/44600*,1067 (*Tynex as given to me from DuPont for aboslute tensile strength/As obtained from DuPont for most reliable tensile strength)
St ,Steel,.281202,350000,7800 (fortepiano.com)
Sk ,Silk,04969,n/a,1378 ( Handbook of Plastic & Elastomers - Westinghouse)
Fb ,FiberFb ,Fiber,.0560,n/a,1553 (density of cotton or wool from Handbook of Plastic & Elastomers)
Bz ,Bronze,.310043,125000,8600 (fortepiano.com)
PB ,Phospher-Bronze,.342133,135000,9490 (fortepiano.com)
Bs ,Brass,.316897,125000,8790 (fortepiano.com)
Cp ,Copper,.29923,55470,8300  (pure, American Institue of Physics)
CF ,Carbon-Fiber,.047589,45000,1320 (these were the values I saw in Harpmakers archive)

Soundboard bowing can be estimated by builder.  It is calculated by a quadratic equation for a very shallow asymmetric parabola, but it approximates what actually happens (in my experience) to a soundboard under tension, i.e., a slight belly at about 2/3 down the center strip.  String tensions can be calculated from the nominal lengths or the bowed lengths (which would best approximate finally string physics under full load).

For a plain or unwound string, diameter is a matter of measuring the nominal thickness of the string.  The measured diameter is directly related to both the mass of the string and the maximum tension the string can withstand.

String diameter and mass calculations.

For a wound string, I use the following equation to calculate the measured or physical diameter (used in string spacing):

(1 * the diameter of the core) + (1 * the padding thickness) + (2 * the diameter of the winding)

Thus, for a Steel/Silk/Nylon string of .018/.004./.013 (or 18/4/13), the physical diameter will be .018 + .004 + .026 = .048

BUT, the MASS of the wound string cannot not be gotten from the measured diameter.  As the conical winding wraps around the core, it does not completely cover the core with its full mass, but rather only about 78% of its mass.  (the shaded area in the illustration is theoretically empty space). Thus for purposes of tuning by tension, the mass becomes .018 + .004 + (.78 *(.013 + .013)) = .04228, or a bit less than the physcial diameter as measured by a micometer.  This smaller value is used by HyperHarp to compute tension for a given frequency.  If you know a better equation, let me know.

The ultimate strength of the string, however, is solely a function of the diameter of the core.  The winding and padding add no appreciable tensile strength to the string.  Therefore, the breaking point of the string is a function of the nominal diameter and tensile strength of only the core material.