Duplex Scale: Enhancing Overtones with String Resonance

The string section between the bridge and the frame of a piano is known as the duplex scale. It enriches the piano’s overtones by creating string resonance.

Like the aliquot strings, the duplex scale is a resonator system. The latter, however, does not use independent (auxiliary) strings, but string sections located outside the area where the hammers strike the strings directly. The purpose of the duplex scale is to enrich the string vibration with a mixture of high frequencies, resulting in a more brilliant sound.

Steinway & Sons patented the duplex scale back when developing the Centennial Concert Grand in 1875. Developed in collaboration with physicist Hermann von Helmholtz, the duplex scale saw its first use in the direct predecessor of the D-274 model, which has been in production since 1884.

String Resonance on Digital Pianos

Modern digital pianos take into account not only the basic sound of the struck note but also many other sound details. In dynamic interaction, these details simulate the complex sound of an acoustic piano. Often, you can even edit them individually, with string resonance, damper resonance, key-off effect, etc. adjustable as desired. Yamaha’s (Piano Room), Kawai’s (Virtual Technician), and Roland’s digital pianos offer a wide range of possibilities to customize the sound…

Roland Piano Designer: Setting the Duplex Scale

Roland’s digital pianos also feature the duplex scale as a parameter in their Piano Designer function. Experimenting with it easily lets you understand its influence: It gives the piano sound more radiance, while the short reverberation of staccato notes is enriched with a high drone.

Keep in mind: In general, less is more when it comes to sound details! As a means of sound design, you can emphasize such details more than you would normally hear on the original instrument. However, always be aware that such interventions may also distort the sound. This is especially true of the duplex scale, which, if over-emphasized, will produce an intrusive high-frequency mix.