Bradley Brookshire and Masayuki Maki brought our dark green 1980 Hyman into beautiful performance condition. Maki took on the initial voicing of the instrument, then Bradley got deeper into the instrument's action, bringing it to the next level, each step contributing to the performance.
Plan view of Hyman LM key (original, at left); key after additional mass removed. - Bradley Brookshire; photo and entry.
This carving of the key lightened the action, as can be seen in the image below, where Bradley compares the weighting of the keys by placing pennies on top of them, and showing how deep the key sinks.
Comparison of back-fall weights: key at left (after non-adaptive mass removed) has more back-fall weight. At the same time, its observable flexion has not increased. Comparison of tap-tones: original Hyman key tap tone = around 660 Hz; after removal of mass = around 260 Hz. That's a big improvement in terms of perceived "clattery-ness" of the keyboard. - Bradley Brookshire; photo and entry.