Young Chang tuning instability

[Ron Nossaman]

> I have regularly tuned a Young Chang PF-250 for about a year, and it 
> sounds horrible every time I come back for another tune.  In the tenor 
> section, one note might be +15 cents, while the one next to it is -15.  
>  Unisons are completely unacceptable.  Bass section and high treble seem 
> to be okay.
>  
> The person who plays this piano is a "Horowitz", plays very hard, but I 
> still think the stability could be better.  Plate bolts are tight, 
> tuning pins have sufficient torque, I have seated strings, and I pound 
> the heck out of it every time I tune. 
>  
> Ideas?  

How many times in the last year have you tuned it, and what 
have the humidity levels been at the time?

With one note in the tenor being +15 cents, and the one next 
it being -15 cents (same bridge, I trust), there are a few 
things it is not. It's not strings that need seated, either on 
the bridge, or coils. It's not loose plate bolts. It's not 
pinblock to flange fit. It's not back separation. It's not 
incorrect downbearing.

It's not uncommon for a piano with a failed soundboard with an 
"s" curved crown to go sharp and flat in odd patterns in 
different areas, but not with adjacent notes on the same 
bridge going in different directions. Same with direct 
sunlight and furnace cycling.

The first most likely cause is that you're pounding too hard 
(or not hard enough) with the tuning, not equalizing string 
segment tensions well, and leaving the piano in an unstable 
state after tuning. Strings commonly creep sharp, or flat in 
this case. As Patric said, go over it twice. If you find 
significant changes on the second pass, that's the problem.

The second is that you have an invisible friend who "touches 
up" the tuning for you between tunings, which invisible 
friends will rarely admit to until cornered.

Who tuned it before you started? Ask them what they 
experienced with it, if they remember.
Ron N