The Harp: A Perfect Union of Design Function and Form

I was recently attending a friend’s harp recital. I rarely listen to harp solos (but I should!), so it was a real treat to my eardrums to hear unique sounds, chords, and transitions that we don’t hear on any other instrument.

I’m no expert, but it seems the harp is relegated to background music (like at a wedding), to supporting the main melodic instruments with glissandos (those full sweeps of many strings in quick succession), or for interesting transitions and special effects in large orchestral music compositions. Thus, it was refreshing to hear some beautiful pieces from a single harp on a stage with no other distractions. It allowed me to focus and appreciate this beautiful instrument, both with my ears and my eyes.

After the recital, I was able to come up and have a close-up inspection of my friend’s harp.  From only a few inches away, I observed some remarkable details and design choices that I had not previously realized. I share a few of these design elements and features below with some thoughts about how they aid in the function and form of this lovely instrument.

The Design of the Strings

There are 47 strings on a typical harp, which means there are 6 full octaves (6 x 7 notes/octave) and another half octave, for the range of notes a harpist can choose to play from. Since a harpist will play at a very acute angle to the strings (meaning he or she will be looking down along the row of strings), the strings are colored in a way to help identify the different strings at a limited view angle. Imagine looking along a fence with your ear touching one of the fence posts. It would be hard to distinguish between fence posts because the angular difference between each post would be small. However, on a harp, every string that corresponds to a C note is designed to be red, and the black strings are the F notes for each octave. So, out of the 47 strings, 6 were red and 6 were black. The others were white or gray. A harpist will use these guiding strings to orient their finger positions for chords and other scales. The function of these colored strings is pretty ingenious, while the balance of color choice or form remains beautiful since 7 different colors for the 7 different notes would be overkill and reduce the overall aesthetic. 

Close-up of red and black strings on a harp.

The strings themselves also have different thicknesses and lengths. I won’t go into the details here of harmonics and vibrating strings, but, essentially, the longer and thicker the string, the lower the tone or note. Usually, the lower notes (and strings) are made of steel and are considered wire strings. The others are made of nylon, and a harpist may have a preference as to where the transition from wire to nylon occurs. Those lower notes are furthest from the harpist and can be plucked a little harder, perhaps with more of the full arm, to reach more resonance. The higher notes are closer to the harpist's shoulder, restricting the movement of their elbow and requiring more movement in the fingers. Since the harp will usually rest on the right shoulder, the left hand is often employed for the lowest notes because the right hand can’t reach as far down. In other words, the right hand can’t reach as far because of the orientation of the typical playing position. Although this may seem like a negative, it allows the harp to be bigger, and thus widens the tonal range, at least at the lower end, at the expense of playing those notes with only one hand.

The Design of the Soundboard

All the strings are attached to a soundboard which can amplify and direct the sound from the vibrating strings. This is similar to the soundboard and f-holes in a violin that transmit and project the generated pressure waves from the vibrations of the hollow body. Since the strings need to be held at precise lengths and tensions, the strings are connected to the soundboard with up to 90 pounds of force. Of course, different strings will have a different tensioning force, but with all 47 strings together, the force the soundboard must withstand can be more than 2000 pounds.

As a result, the design of the soundboard is a key component of the harp that needs to be carefully considered. Changes in humidity, temperature, and usage can contribute to the flexing of the wood and cause it to crack and eventually break with such high tension from the strings. For this reason, I learned that one can be quite anxious if wanting to buy a used harp. The new owner can’t be certain of the conditions that the old owner kept and used the harp and potentially ate away at the life of the soundboard. After all, dropping a harp can cause damage to the fibers even if it isn’t visible on the outside.

The shape of soundboards can vary to some degree as long as the function of supporting strings and magnifying sound is satisfied. Many harps soundboards will have ornamentation, various curves, or the wood grain exposed, allowing a harp designer to explore form beyond the required soundboard’s function.

Main Parts of a Harp [1]

The Design of the Pedals

Having 47 strings seems like a lot on a harp (violins only have 4!), but those 47 notes can be modified into sharps and flats (i.e. semitones), a slightly higher or lower tone for every string, respectively. A harpist doesn’t have time, or enough arms, to shorten or lengthen the strings while concurrently playing with both hands to make sharps and flats, but they do have feet. As a result, modern harp designs have pedals that will actuate a small mechanism at the top of the harp to change the length of the string and thus the tone. These are unsurprisingly called pedal harps.

Understandably, there isn’t space for 47 pedals. There are, however, 7 pedals, one for each of the notes in the diatonic scale (C,D,E,F,G,A,B). In other words, there is a pedal for all the C strings, a second pedal for the D strings, and so on. All C strings can be made to be flat, sharp, or remain as natural but all at the same time. You can’t have a flat C on one octave, and a sharp C on another octave on the same harp at the same time, but usually this isn’t a problem at all. To overcome this limitation, a different design, with individual levers for every string, called the lever harp can allow for more mixed semitones, but it does require the harpist to change levels with their hands while playing.

For a pedal harp, the 7 pedals will thus be in three possible positions, at the top position for flats, the middle position for naturals, and the bottom position for sharps. The further one pushes the pedals in the three levels, the shorter the strings become and the higher the pitch via the rotation of special discs shown below.

Disc positions for flat (left), natural (middle) and sharp (right) notes. [1]

A transparent harp neck showing arms and mechanisms for adjusting string length. [1]

The amazing design feature is that the pedals are at the bottom and the pedals mechanisms (including pedal discs and pins) are at the top of the harp, often called the harp’s neck. The propagated actuation between these systems is accomplished by moving and rotating rods and arms that are hidden inside the column of the harp. The following schematic shows the layout of the seven pedals (top) and then a side view of the pedal with the arms and rods going up the column (bottom and right side).

In terms of the balance between form and function, I find that hiding the pedal rods and other links inside the column and neck, but exposing the pedal discs and their motions as the strings’ lengths are adjusted is a masterful choice. It allows the designer to add flare and personality to the outside of the harp’s column, while concurrently allowing the 7 rods to keep moving up and down as the workhorse of mechanism actuation inside. Opposingly, I like the exposed discs and their operation on the outside. There is something beautiful about the synchrony of the rotating discs for every pedal adjustment that truly is functionally-based, but lovely in form.

Details and layout of pedals, arms, and rods inside harp base and column. [2]

The Design of the Curved Neck

One could ask why the neck (at the top) has to be curved or bent in a special way and not flat or straight like the soundboard at the bottom. Perhaps the main reason is that it allows for an exponential growth in string length from the high notes to the low notes .In contrast, a linear growth curve might require the short/high strings to be so thin and short that it could be hard to interact with them using average sizes of hands and fingers. The curve at the end also permits a more reasonable size and length of string. Strings that have to be so thin and short might break more often. The angle itself also provides a better alignment with the soundboard and a more ergonomic design, such that the part of the strings at which the harpist is playing is maximally comfortable. In other words, sometimes the strings are plucked at the relative top and sometimes at the relative bottom based on the point with respect to the neck, but they are equally comfortable for the harpist.

Lastly, the shape itself, often called an ogive, is aesthetically pleasing to the eye and adds beauty to the design. Compared to how some other instruments look, the harp is truly elegant.  In contrast, the designs of brass instruments, such as the tuba or trombone, are essential and produce beautiful sound, but they don’t look objectively beautiful, mostly because they are constrained by certain tube lengths, tube radii, and horn sizes.

Conclusion

The harp is an instrument that is both beautifully sounding and beautifully designed. It has a wonderful mix of materials, geometry, and features that make it a lovely instrument to play, hear, and see. Although any design should be functional and meet its intended requirements, there is something magical when those requirements can also be met by looking fantastic. The harp strikes a perfect balance between function and form.  

[1] https://www.harp-school.com/guides/choose-your-harp/

[2] https://bt.barnard.edu/ave2015/project2/mechanical-furniture/the-harp/