WIDesigner Options - edwardkort/WWIDesigner GitHub Wiki

Options Dialog

Use the WIDesigner options dialog, at Edit-->Options..., to select a study model, and configure the program's other parameters and settings.

• Study Model
• Length Type
• Air Parameters
• Constraints Directory
• Note Spectrum multiplier
• Blowing Level

Study Model

The NAF Study Model predicts a nominal playing frequency for each note, and offers geometry optimizers suited for the design of Native American Flutes. The Whistle Study Model and Flute Study Model predict a minimum and maximum playing frequency for each note along with a nominal playing frequency, and offer geometry optimizers for tonehole and bore geometry. The Reed Study Model supports single and double reeds, as well as some lip reeds, predicting a nominal playing frequency for each note, with optimizers for tonehole geometry and bore profile appropriate to reed instruments.

Length Type

Length Type controls what units WIDesigner uses when displaying lengths. Options are MM (millimeters), CM (centimeters), M (meters), IN (inches), FT (feet).

Air Parameters

WIDesigner uses air parameters to calculate the speed of sound, and other properties of the air within the body of the instrument. All study models use the air temperature (in Celsius) and relative humidity (in percent). The whistle, flute and reed study models also use the absolute air pressure (in kiloPascals) and the CO2 concentration (in parts per million). The air pressure is the actual absolute air pressure, not a barometric pressure that has been corrected to sea level pressure. Air at sea level has a nominal pressure of 101.325 kPa. Air pressure decreases with increasing altitude, about 1.2 kPa for every 100 meters at low altitudes. Although air pressure does not affect the speed of sound directly, it does alter the effect of humidity and CO2 concentration. Ambient air has a CO2 concentration around 390 ppm. For mouth-blown instruments, we suggest you use a relative humidity of up to 100%, and a CO2 concentration of 40000 ppm.

Constraints Directory

WIDesigner uses a multi-level directory structure for storing constraints files that apply to various instruments and optimizers. Enter the root of this directory structure in the constraints directory field. This is generally the constraints directory included in the WIDesigner release directory. WIDesigner uses the constraints directories for constraints file operations on the File menu.

Note Spectrum Multiplier

The Max Note Spectrum frequency multiplier field controls the upper limit shown on the Note Spectrum Graph; the highest frequency shown is the target frequency times this multiplier. The default value is 3.17, or just above the third harmonic.

Blowing Level

The whistle study model and flute study model, because they model a range of possible frequencies for each note, need an indication of how hard you like to blow your instrument. You may tend to blow a whistle hard, so that notes are approaching the point where they break into the next register; or you may tend to blow a whistle softly, so that notes in the upper register approach the point where they drop into the lower register. The blowing level attempts to quantify this with an abstract number, from 0 (softest blowing) to 10 (hardest blowing).

The blowing level affects only the whistle or flute model's prediction of nominal playing frequency. It does not affect the prediction of minimum or maximum frequencies. The nominal playing frequency appears in the Predicted column of the tuning table, and as a line of open blue circles on the tuning graph.

For wide-bore, single-octave, instruments, we suggest you try blowing level 10 to start. For flutes, we suggest you try blowing level 9. For most whistles, you may need to try several values, starting around 3 or 4, to find which one best reflects how you play. High blowing levels have the nominal playing frequency for the lowest note high, close to the maximum frequency for the note, and the nominal playing frequency for the highest note low, close to the minimum frequency for the note. Lower blowing levels have the nominal playing frequency lower at the lowest note and higher at the highest note.

If you have a model for a real instrument and measurements of your actual playing frequencies on that instrument, you can try different blowing level settings to see which one predicts nominal playing frequencies closest to your actual playing frequencies.