How to Use the Calculator
- Enter values for the known parameters of a string in the dark grey cells and click on the [calculate] button. DO NOT hit ENTER or RETURN on your keyboard – on some systems this will reset the calculator. Should this happen you may be able to restore the values previously entered by using the back button in your browser.
- Values for additional parameters will appear in the lower rows [orange], copy these values in the relevant boxes in the top dark grey row and click on the [calculate] button again.
- Repeat until all the cells have been filled and all three rows in the first section match. Note that a margin of error will occur in some calculations as a result of rounding off.
- If all the fields cannot be filled estimated values must be entered to complete the calculations. Note that not all calculations require all fields to be filled.
- Section 2 Strength requires yield strength and diameter.
- Section 3 Inharmonicity requires length, diameter, frequency, density and elasticity.
- Section 4 Lateral Resistance requires length, diameter and tension, Elastic Potential Energy requires length, diameter, tension and elasticity; plucking point and depth are also required for both.
- In section 5 data for multiple string configurations can be saved for comparison. Simply click the save button and values entered will be saved in .csv format (comma separated values). New values can then be entered and save on the next line. This data can be copied and pasted into a text editor and saved as a .csv file. The file can then be opened in MS Excel or a similar program to facilitate comparisons. Parameters can be named by entering text in the relevant field e.g. length, diameter etc. click ‘save’ and replace the text with the appropriate values and save again. The columns in the spreadsheet document will then be labelled appropriately. To copy the data for export in Firefox hold down the option key and drag across the text to select, for IE and Safari drag across the text to select as normal.
Popup instructions are available by clicking the [enable popups] button. Popups will appear on holding the cursor over a cell and disappear when clicked or moving the cursor away. This option is disabled by default.
Values entered for the different parameters must adhere to the correct format or else the calculator will return misleading or impossible results.
- Length should be expressed in metres m
- Diameter in millimetres mm
- Density in g/cm3
- Mass in grams g
- Linear density or mass per unit length in grams per metre g/m
- Tension in kilograms force kgf (1 kgf corresponds to the force exerted downwards by a mass of 1 kilogram at sea level)
- Frequency in Hertz Hz
- Yield strength in megapascals MPa
- Young’s modulus in gigapascals GPa
A unit converter is also provided to convert from imperial units.
Table 1 presents typical values for the modulus of elasticity, yield strength and density of modern string materials commonly used on metal-strung harps.
Table 2 provides frequency equivalents for note names from bass C (C2) to c'''' (C7).
Table 3 provides data for wound strings.
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Submitted by Paul Dooley, 21 March, 2013. © 2004-2013 Paul Dooley
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