Back check study

[Clark]

I've heard about a study performed by Yamaha regarding the role of the
back check in repetition, I think in uprights. Could someone provide a
reference toward this?

We have an 1850s Hallet & Davis grand which is similar to the instrument
in the Boston Museum of Fine Arts, though possibly earlier. Its action
is essentially a single action as featured in later, larger squares -
however the back check is fitted on a lever so that when a key is
pressed the back check rises faster than the key end. Checking is done
on the hammer tail as usual.

It was obtained for the right price: five big squares.

Unfortunately the piano won't be in playing condition for some time, but
it would be interesting to compare the findings of the study with this
application of the back check. If anyone is interested, I should have a
scale drawing of it in the next couple months.

Clark