[pianotech] phenomana - Another ETD Check

[Ron Nossaman]

On 5/14/2012 11:38 PM, Joseph Garrett wrote:

> Ron,
> I have a sneaking hunch what you are alluding to.<G>


Sorry Joe, that wasn't intended to be so terse. I think the coffee's 
working now.

But yea, the different readings reported by ETD users in different 
seasons is pointing to something that changes in the piano regarding not 
only the need to adjust pitch (obvious), but the indication that the 
finished tunings produced aren't the same from season to season. This 
has been mentioned occasionally since the SAT first showed up, but to my 
knowledge no one has ever saved these differing tunings for comparison 
of the offsets note by note. I think that has the potential for teaching 
us something.

As usual, I'm trying up front to head off the volume of descriptions of 
workarounds, octave ratios, stretch manipulations, and other 
customizations and peripheral esoterica universally accompanying 
discussions of ETD tuning, by trying to explain what I'm after. Though 
this has nearly never worked in the past on any given subject, I don't 
know any other way to ask.

So in order to get anything at all useful from the data, I need 
duplicate processes (as is possible) producing the tunings, so we can 
see what the piano is actually doing season to season without 
contaminating the data with changing input.

So with an aurally super tuned testing piano serving as probably the 
most reproducible aural tuning, What are the recorded note by note 
differences with a 30%RH difference when the tunings were done?

I'm not sure how to do this with an ETD. Since I'm not after the ideal 
*result*, but rather the difference in results with the same machine 
setup, I don't know what to specify. But, again, I'd like the note by 
note offset differences of the results. I don't know, but I probably 
need an *ideal* version too, with tweaks as necessary since that happens 
in the interval checks with the aural tuning. Like anything, I won't 
know what I need until I find out by wading through what it turns out I 
don't need. That just seems to be the way things work, and at the end, I 
may still not know. But such is the process.

If I can get clean data from as near identical input from both methods, 
there should be a correlation in the recorded note by note offset 
results that represents how the soundboard assembly is filtering and 
changing the process that we can separate from the tuning method and get 
some idea what we're actually dealing with in trying to tune these 
things. I still maintain that pianos can't be tuned, much less be kept 
in tune, but I'd like to try to understand more about the why of it with 
the tools available. Unfortunately, I haven't the means to do it myself 
and am asking for help.

I think that's more like what I mean.
Ron N