Bass strings on yamaha grand

[Ron Nossaman]

>
>My experience mirrors yours, but its still leaves me with some
>unanswered questions.  I once found a Yamaha studio piano in a Shakey's
>Pizza Parlor where the bass strings went way beyond 'tubby' to nearly
>INAUDIBLE.  I replaced a set on a Yamaha studio in a nursing home a few
>years ago: now they're starting to get that characteristic dead sound. 
>In both cases (and there have been others) there is a distinct
>possibility that spills have occurred, but wouldn't you expect to see
>more unevenness in the sound?  Why does this subject always come up with
>the  Yamaha name attached (besides the fact that they are very popular
>institutional instruments)?  Why would new Mapes strings eventually
>suffer the same fate?  I have suspected structural problems, but have
>not found anything so far.
>
>I'm not a Yamaha basher - I have many in my clientel that I look forward
>to servicing - but the coincidence is fairly strong.
>
>
>Carl Root, RPT
>Rockville, MD
>

Hi Carl, Wim, and list.
I would tend to think it isn't structural or replacing the strings wouldn't
take care of it. Nor would structural problems make a new set of strings
that sounded fine at installation, go dead with time. A bass string is two
metals from considerably different positions on what I learned as the
electromotive series. I think it's called a galvanic action series, or chart
now. High carbon steel, with no protective coating, in contact with a copper
alloy is a corrosion cell waiting for an electrolyte. Liquid spills, and
even moderate levels of humidity, especially with temperature changes, will
activate the corrosion process. It happens in all bass strings eventually,
but you new that. Why the apparent high incidence in Yamahas? I don't know,
since I haven't noticed any particular problem here (and probably still
wouldn't know if I had). If the general consensus is that it seems to happen
more (proportionally, not numerically) to Yamahas than to other brands in
similar circumstances, and with replacement strings from another source,
then maybe it's coming from inside the case. Out gassing from MDF, plastics,
finish materials, felt treatments, or the dreaded select hardwoods.
Everything on the planet seems to exude something, and the gas mix peculiar
to the insides of Yamahas may accelerate the corrosion process. 

Airborne grease from cooking could be a factor in the restaurants and
nursing homes (the piano's always in the dining area), but not primarily to
Yamaha.

Just another possibility.
    
 Ron