A Simple Approach for Matching Hammer Weight and Action Ratio in the Grand Piano to Control Inertial Playing Quality – By David Stanwood
Our piano industry holds the belief that a high, medium, or low Down Weight is associated with a heavy, medium, or light action. Experience teaches that the association is unreliable. A well voiced and regulated piano with a medium Down Weight can sometimes feel heavy or light. The underlying and overriding factor is the “Inertia” of the leveraged hammer weights. The normal range of Leverage Ratio and Hammer Weight levels in grand pianos varies widely and finding the correct match is key to producing a desired playing quality. When Ratio and Hammer Weight levels are paired for specified Inertial types, the amount of weight needed to balance the keys to a specified Down and Up Weight is always similar. This leads to a simple, practical, and calculation free approach. A handful of “Marker” keysticks are tipped onto a digital scale and the weights set on top to mock up a normalized Front Weight associated with the desired inertia according to reference tables. The mocked up keysticks are installed and the weight of each hammer on the marker notes is adjusted to produce the specified Touch Weight. Once the correct Hammer Weight scale is established and the action balanced with key weights, the desired quality of Inertia will result.
David Stanwood discovered the Equation of Balance and pioneered the field of Touch Weight Metrology. He is the inventor of his trademark product – Precision Touch Design. For 3 decades he has practiced and taught his methods for scaling Hammer Strike Weights and Key Front Weights. His work produces the intended Inertial Playing Quality with the smoothest possible touch response from key to key. David was inducted into the Piano Technicians Guild Hall of Fame 2019. The Precision Touch Design Academy Europe was founded on his method in 2008. He received the Distinguished Alumni Award from the North Bennet Street School, Boston, Massachusetts, USA 2007. He lives and works on the Island of Martha’s Vineyard off the North East coast of the United States.