Genuine silk wound basses for harp "AR"

Why strings with silk cores?

From the few historical and iconographical sources in our possession, we know that the harp began to use wound bass strings in the mid-18th century. These strings consisted of silver-plated copper wire wrapped over a parallel silk filament core.

Despite Erard (1830-35) introduced such bass strings with metal and silk cores, strings with silk cores alone remained the most common commercial choice until the end of the 19th century.

With the increasing popularity of metal-cored bass strings and the increase in tension, the interest in silk strings declined.

What are the mechanical and acoustic differences between a silk and a nylon multifilament core?

The introduction of polyamides (Nylon) around 1950 has contributed decisively to the demise of silk as cores in bass harp strings.

Nylon strings present two characteristic aspects: a greater elongation of the string (that translates into a higher number of turns on the peg) and a markedly brighter and more persistent sound.

Silk strings, on the other hand, stretch way less, have a warmer sound and have a more percussive sound: that was exactly the type of sound that was heard in the 18th and 19th centuries.

What construction criteria was adopted?

The most problematic aspect concerned the criterion for choosing the proper percentage between metal wire and silk core (also defined as Metallicity Index); in fact, under the same working tension, strings can be made where the metal coating is more or less influential: when metal prevails, the sound will result brighter, and vice versa.

After careful studies, when choosing the metal/core ratio, we therefore decided to adopt the same data obtained from the measurements on original series of basses dating back to 1797 and perfectly preserved in Paris (Baud: https://www.jstor.org/stable/841675 e https://www.jstor.org/stable/842477).

However, there are two main issues:

1. Baud’s series of silk-coated strings was only designed for a 37-string harp, while during the 19th century several other basses were added to the harps;
2. most of the harps that are used today are not copies of original instruments, but actually more or less restored original instruments: therefore, installing strings with the supposed tension values used in the past is quite risky.

Having calculated a linear correlation between the core/metal proportions of Baud’s original set of strings, we have therefore extended the range of available strings, both on the thinner side and on the thicker side, using the same constructional proportions.  In other words, from the range of Baud’s strings (2.00-3.74 mm in equivalent gut) we have reached a value of 1.75 mm in the high range and 5.04 mm in the low range (for XIX century harps).

How does our coding work?

The numerical part of our AR codes expresses the theoretical diameter of the hypothetical natural gut string (i.e. its ‘gut equivalent’)

For example: 212AR means that the silk-core wound string has an equivalent gut diameter of 2.12 mm (useful for calculations).

Please note: the progression of diameters in our AR series proceeds in increasing intervals of one semitone at a time starting with the thinnest at 178AR.