THAT MYSTERIOUS BACK CHECK

[oorebeek]

And here we are again.
This time I have an interesting issue about sound improvement by =
changing the position of a back check. I learned this at my last =
course in Hamamatsu.
It is as follows: a couple of days ago I was asked to go to a Yamaha =
dealer who had a complaint about a new Yamaha S6 (the handmade Yamaha =
copy of the Steinway B, for those who do not know) being too soft.
There was no power in it due to very bad regulation.
So first I checked the down weight, found it a bit high, and made the =
action a bit faster so that the down weight was a little less (just a =
little, mind you).
I then made a complete regulation from beginning to end followed by a =
tuning.
The treble was OK now but the base was still too weak. I decided to =
use the trick with the back check.
Here it comes:
Take the action out, put it on a bench or table.
Push down a key (belonging to the soft sounding part) very slowly, =
you feel the motion of hammer drop (careful now) you keep the key =
pressed down, you look at the exact space between the lowest point of =
the hammer tail and the highest point of the back check.
How much is it? is it 3 mm (sorry again, darned europeans) is it =
more? When the distance between these two points is more than 2 mm, =
screw the back check one complete turn (360=9A) up.
In Japan every technician has a custom made hardwood pipe which fits =
over the back check (a rectangular hole).
Put the action back. Now listen again, you'll be amazed! This one key =
sounds better, it has more power than before!
Just make sure that the distance is not less, than 2 mm!
And if you have to turn the back check down, be careful, the metal =
thread might break.
This is a very powerful trick!
Naturally, everybody knew this allready and therefore my question to =
yall is:
What is the explanation for this???????
My teacher in Japan did not know. Nobody I asked here in Holland has =
an answer.

WHO does?

PS. don't forget to check the hammer blow distance...


friendly greetings from:

Andr=E9 Oorebeek
CONCERT PIANO SERVICE
Amsterdam, the Netherlands
email: oorebeek@euronet.nl

=83  where MUSIC is no harm can be  =83