So I've been thinkin'.... (I know, often dangerous!) Since the point of the experiment is to document where, if there is any change to an aural-type tuning with change in humidity,we shouldn't need to emulate a master tuning. As long as each individual Verituner tech keeps the same style for different seasons, the experiment should work. I'm guessing we're looking for at least 20-30 percentage points in relative humidity change. We should document:piano model, bridge break location, stringing break location, if not at bridge break.... strut locations? (what else?)Relative humidity saved with file name. Make sure to fill the "I"s as much as possible with a single string - picking the clearest one.Save the files, but I suppose we could graph just the RPT test partials for comparison?A0-B2 - 6th C3-B4 - 4th C5- B5 - 2nd C6-C8 - 1st Here's the Verituner-specific part: I don't think we should use the built-in styles... I'm often asked why I spent so much time on the custom styles, when the built-in ones do such a good job. For me it comes down to fudge-factors. (This is gonna get a little wonky here.) The Verituner calculates the temperament octave based on a directed octave width, then every other section is controlled by another set of comparisons of calculated beat rates based on both the inharmonicity data collected and the strength of the sounding partials. The Verituner makes a target for a number of partials and then (hidden to us, though you can see it in measure mode) has a spinner for each partial. There is a combination of all of these spinners to drive the main spinner/needle that we see in tuning mode. Where's the fudge factor? Let's consider just the temperament octave. Aurally for most decent size pianos, we'd like to use multiple checks to determine that the A3-A4 octave is set about half way between a 4:2 and a 6:3 octave. With a custom style, this is pretty easy to set up. We set the beats to zero (comparing 'pure' octave matches) and weight each octave type 50%. (they should always add up to 100%) Different size pianos "want" different widths to the temperament... Compare that with the built in average style. (go to the style menu, choose built-in, highlight average and then choose design) You'll see that the A3-A4 octave is set using only the 4:2 octave match, just set about 1/3bps wide of pure. While this often makes the tuning end up in the same place, I've always thought it best to include more "checks" into the process. Each other section of the piano is also set using single partial checks between octave or other interval types with the built-in styles. I'd be happy to help any tech set up an appropriate custom style for the specific piano you will be testing. There is an export program available that allows you to dump the tuning targets into a spread sheet. We should probably make multiple files (fill the "I"s again) at each measured humidity to get a range of variability of the Verituner... Any other suggestions before we begin? We're still somewhere around 40%RH most places indoors around Chicago. Ron Koval -------------- next part -------------- An HTML attachment was scrubbed... URL: <https://www.moypiano.com/ptg/pianotech.php/attachments/20120518/75a7e824/attachment.htm>
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