The compiled data that supports the analysis of each sound presented in Chapter 4, is presented in the appendices in part II:

Appendix 1: String Scales;
Appendix 3:Soundboard Vibrations;
Appendix 4: SPL (loudness);Rate of DecayCalculations; Audio Sounds Index.

Stuart Design Concepts – relating to tonal colour outcomes

• The faster rate of decay in the onset of the Stuart string vibration was found to occur because of less resistance to the vertical plane of the hammer strike, due to its vertical coupling. The larger amplitudes of the Stuart Fnd., 2nd and 3rd partials, subsequently causes a faster inverse decay reaction in the onset of the sound.
• The Stuart’s earlier change into the slower decay rate (after-sound) is due to a proportionally smaller change in the vibrational mode from vertical to elliptical, ie less damping, which is heard in the stability of the tonal balance of the after-sound.

Changes in [vibration] mode = damping. No change [in vibrational mode] can contribute to a greater motion and quicker loss as your figures indicate but the lack of subsequent changes in mode ultimately reduces the overall [energy] loss in comparison to the ever changing back and forth motions of the pinned bridge scenario.²⁴¹

• Thehigher degree of stress on the horizontally pinned string of the Steinway, when forced into the vertical plane by the hammer strike, causes a higher amount of damping, resulting in a longer inverse decay rate at the onset, of smaller gradations , subsequently losing more energy over a longer period, before settling into its after-sound.

²⁴¹Wayne Stuart, email interview with author, 22nd June, 2015.