[pianotech] was crown and radius now displacement under load

[Gene Nelson]

> Try to measure board excursion during play. In the low bass,
> with the panel floated, you can get visible movement, but even then, it's 
> not a lot.

Panel is floated, motion observed and it is not much - guess about <0.5mm. 
Have considered trying to mount a fine pencil on the bridge and paper to 
stationary component like the rim to see if it can be measured somehow - 
another day maybe.
Thanks.
Gene