[pianotech] DC (was:To unplug or not to unplug)

[Alan Eder]

It's really noticeable with seasonal changes, which would be humidity.

And if the seasonal changes are humidity-caused, and the soundboard is NOT actually rising and falling (as many of us had thought), what IS the humidity doing to effect the exaggerated changes in pitch in the low tenor and lower lower-treble areas?  (Apologies in advance if your previous discussions of this phenomenon has not yet fully penetrated my dwindling gray matter).


Thanks,


Alan Eder


-----Original Message-----
From: Ron Nossaman <rnossaman at cox.net>
To: pianotech <pianotech at ptg.org>
Sent: Tue, Jan 25, 2011 4:41 am
Subject: Re: [pianotech] DC (was:To unplug or not to unplug)


On 1/25/2011 11:30 AM, Alan Eder wrote:
> Ron,
>
> Thanks for the explanation--good information.
>
>     The lower the break% of the
>     wire, the more it reacts to minor tension changes.
>
> And those tension changes could be brought about by temperature and/or
> humidity changes, or is it temperature alone?

It's really noticeable with seasonal changes, which would be humidity. 
It ought to work the same way with short term temperature changes, but I 
haven't verified that. Has anyone out there had one of my pianos under 
stage lights? When I'm laying out a new scale and bridges, I try to 
minimize break% changes across struts by maintaining speaking length 
progressions with adequate bridge doglegs. In the low tenor, a 
transition bridge with wrapped bichords can substitute for the 
foreshortened original low tenor wire, and get the break% up where it's 
less reactive. Both of these things help tremendously. Add an epoxy 
laminated cap, and the tuning becomes much more humidity change tolerant.
Ron N


 
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