[pianotech] Diaphragmizing

[V T]

Hello,

I am curious about one piano that for me stands out w.r.t. bass, the M&H
9 ft. concert grand. Unfortunately, I am not sure which vintage I am
talking about. I have listened to several of these and, without exception
they had an excellent tone in the low bass. Can anyone here tell us more
about those soundboards? I wonder if and how much they are thined along the
edge.

Vladan