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Harp Myth 2
This article is the second in an extended series of articles addressing issues and myths surrounding traditional harps and their construction.
Standard String Spacing, Please
According to Webster's digital dictionary, a standard is defined as: something set up and established by authority as a rule for the measure of quantity, weight, extent, value, or quality. According to the authority and custom of lutherie, there is a firmly established standard for violin string length and tension. Variants exist but there is a written, well known standard that is acknowledged by all lutheries worldwide. The same is true of guitars. Traditional Harps have no such standard. What is mistakenly referred to as "standard" is generally the Lyon and Healy "concert spacing".
String spacing in any stringed instrument is driven by two factors: the mechanical space required for a given string type to freely vibrate when properly activated and the ergonomics of the human player. The minimum amount of mechanical space required is a mathematically calculable formula. While it is true that higher tension reduces the amount of mechanical space necessary, modern nylon strings reach the maximum point of elasticity at 70% of their tensile strength. Beyond 70% they cease to stretch evenly. Wire strings need to be above the 70% point to optimally voice. Of course, if the string tension is too great, the soundboard will require additional bracing or thickness, neither of which is desirable. Harps are designed around specific string types, lengths and tension. The soundboard and back of the soundbox are built to accommodate the strings selected. [This is why it is dangerous to change string types without checking with the lutherie. Strings which drive the harp beyond the design envelope both destroy the harp and, generally, negate the warranty.]
"Concert spacing" is not a design parameter necessitated by the physics of the instrument itself. Harp lutheries which use even spacing are relying on the piano's concept of even spacing regardless of octave. Ergonomically, the piano works well with even spacing because the person playing is using a palms down, wrists rotated, ball of the finger action. Since human hands and fingers fall within a general size range, the minimum width of keys is basically dictated to piano builders. Harps are not an equally obvious choice for even spacing. Both harpers and harpists play with wrists straight and palms in their natural inward facing position enabling the fingers to attack the strings utilizing a smaller surface: the finger tip, edge or nail. Since harps do not have the large attack surface requirements of the piano, the shorter the distance a finger has to move, the faster it can be operated. The advantage of reduced finger travel distance applies down to 12.5mm. Spacing below 12.5mm is too narrow for the size of the average finger and the spacing itself becomes an error agent.
Harps which are built to best accommodate the human hand have graduated spacing. Graduated spacing means that above the 12.5mm threshold, strings are generally spaced as close together as mechanically possible. This results in shorter strings being spaced closer together than longer strings. Beyond ease of play, the other major advantage of graduated spacing over even spacing is that the harmonic arch does not have to be as long. A shorter harmonic arch decreases the overall depth of the harp. This eases shoulder strain by minimizing the amount of forced reach and the accompanying shoulder rotation. A shorter harmonic arch also generally means a comparatively smaller, lighter instrument. In these days of carpal tunnel syndrome and common back ailments, ergonomic design is increasingly important.
String tension is a subject around which there is considerable misinformation. The idea exists that lower tension harps are somehow inferior. The misunderstandings about string tension generally fall into two areas, design/voice decisions and technique. All other things being equal, instruments at higher tension tend toward a more pronounced treble voice with shorter sustain and lower tension instruments conversely exhibit a mellower, bass voice with longer sustain. Higher tension strings require a stronger attack by the player to yield optimal activation. In any given harp plan, the luthier first has in his/her "mind's ear" the voice the instrument is meant to achieve, the type of player for whom the harp is intended and the price point at which the harp will sell. Decisions made about string tension are intimately tied to these parameters.
As a side note, historical harps during the Renaissance all had lower string tension. Wire strings made during the period were brittle and the chemical structures prone to fissure failure. Gut strings could not be put under high tension because once tightened they continued to stretch until they were once again at a lower tension. The lower tension of Renaissance period harps gave them the softer, lighter voices which we today associate with Renaissance harp contemporaries like the lute, psaltery and harpsichord.
The second misunderstanding related to string tension has to do with technique. Like guitars, harps with different string tensions allow for distinction in technique. Every harp is not for every player. A sophisticated harp customer evaluates a harp within the bounds of the technique(s) appropriate to that individual instrument.
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