A door harp is a hollow, flat box with hanging balls that gently bounce off strings tuned to various notes. When placed outside the home, these ornate ornaments can have as few as three strings or as many as a dozen or more for a simple or complex panoply of sound that changes with the breeze. When a door harp is placed on the inside, as is customary, it makes a distinctive noise for the residents whenever the door is opened and closed.
The door harp has evolved over at least three centuries in Scandinavia, primarily in Sweden, but also in Norway and Denmark. These ornaments, derived from a few styles of Chinese stringed instruments called the guqin and the ruan, are thought to have been made for as long as 700 years. The door harp, on the other hand, is meant to be enjoyed rather than played.
Door harps are thin soundboard boxes made of various hardwoods with one or more sound holes in the front. The boxes come in a variety of shapes, including hearts, tears, and ovals, as well as round, square, and rectangular shapes. The more unusual the design, the higher its value as a work of art will be. Lacquer, lemon oil, or beeswax are commonly used to finish these hangings. Their fronts can also be found with designs painted on them.
The complexity of the sound produced by a door harp is determined by the number of strings it has. Vertical strings of varying lengths are attached in a single row along the top of the door harp to hang wooden clapper balls. Each vertical string will allow the ball to fall to a different horizontal string as it descends. There is one ball per horizontal string, which can range from three to a dozen or more notes, resulting in warbling chords of random music when the balls bounce.
Some people use a tuning wrench to tighten their door harp’s end points, or zither pins. This will result in a set of notes that are perfectly tuned. The strings are usually made of wire, but some are made with braided silk in the old-fashioned way.
Some people display their door harps on the outside of a door to welcome visitors or on a wall near an open window. However, it is customary to hang them inside the front door so that music can be heard whenever someone enters or exits. In addition to homes, many Swedish shops will have a door harp inside to notify the shopkeeper of a new customer’s arrival.