Tuning a Kawai Grand RX-2

[Ron Nossaman]

> I'm interested in this thread because I've a similar problem with a Kawai.
> Ron,
> Backscale, sounds reasonable then to stretch and settle the back scale.?.?
> Fenton

I don't think so, because the back scale isn't unstretched or 
unsettled. The line of thought that, in thirty years, has 
gotten me to this point is this: When the slightest movement 
of tuning pin by the hammer results in a detectable change in 
speaking length pitch, and you can easily control the thing, 
by speaking length pitch and the feel of what's happening in 
the hammer, and it survives whatever test blow(s) you're 
fondest of, your problem isn't from the speaking length bridge 
pin forward. Why? Because you've moved all that, felt it move, 
heard the results, and being a competent tech with some years' 
experience, left it in a stable state. What you don't know, 
and what no amount of magic hammer technique will EVER tell 
you is the condition of the segments behind the front bridge 
pin row. You have no way of ascertaining what's waiting for 
you back there - NONE. You can't feel what's there because you 
likely haven't made a big enough tension difference during 
tuning (unless you raised pitch substantially), to overcome 
the bridge pin friction points and detect the resulting 
movement. So you basically take what you can get. If you pound 
too hard during tuning, you can pull some of that back scale 
through the bridge, leaving the rear segment tensions higher 
than what you settle the front lengths to by listening to the 
speaking length. Later, with the tiny movements of temperature 
and later humidity changes, the tensions will tend to equalize 
some and the speaking length will go sharp. If the back 
lengths are of lower tension when you tune it (which you can't 
know) and you can't manage to pull the string through the 
bridge with test blows, the speaking length pitch will drop 
later either by those same temperature changes, or by someone 
hitting it harder in play than you did tuning it. Where do you 
suppose the pitch drop comes from when a test blow knocks the 
tuning out? Being a competent tuner, you left the front 
segments in good shape, so what happened. The back scale 
happened. The back lengths are a real crap shoot. Sure, you 
can push on them massage them, stretch them, yell at them, or 
anything else you want to try to drive out the evil spirits, 
but the bottom line is that when you have no way to directly 
compare the front and back length tensions, you have no way of 
know if you're improving the situation or making it worse. The 
only way I know of to produce a dependably stable tuning is to 
tune often, on a piano that is under rigidly controlled 
temperature and humidity conditions, and move things as little 
as possible doing it.

I'm, on the way out the door, so won't take the time to proof 
this for psychotic sentence structure or strange inside out 
disconnections. If there are any, sorry.

That's essentially it.
Ron N