[pianotech] phenomana - experiment.

[David Renaud]

Another point to add information into this window in master tuning procedure......

It is common on the master to let the piano dictate how wide exactly between the 
4:2 and 6:3 to make those first octaves. Piling thirds, and finding the "middle" place 
For the middle third. Even if the given temporary octave is "wrong" , too wide or too 
Narrow, the placement of the middle note for the middle place remains the same. And
So we go around a divorce of thirds always placing the middle one. Here the accuracy 
Is only restricted by our ability to perceive that middle beat speed. So there is technique to allow the piano to speak to us and dictate the initial Placement. You likely very well know this already.

My purpose is to share that this technique is used n some master tunings and does result
In something wider then 4:2.

The rumor about 4:2 likely comes from trying to give candidates a test to hold onto that 
Will get them close enough and within tolerances to pass. The master does not literally 
Follow 4:2, as you can see from the various procedures Shared..........
There is room for some debate here among CTE's.  Never less, the tests I am sharing are 
The actual tests I have witnessed, and practiced. 
    Approaching the bass in a master i was chastised once for going to quickly to a 6:3, and 
Encouraged to favor the 4:2, but I was not literally asked to follow the 4:2, just to favor it more.
There remains some debate, and a little push and pull of people's ideas. All around there
Is recognition that there is room within the tolerances for a little play/style variation, at the same time as wanting consistency between masters. Thus, the negotiation in the exam room can take 
Some time, and can be an enlightening experience, as people advocate for there preferences within the perimeters given. I like Jim colmans test for treble stretch shared in the last email, because it nails Down a subjective decision for consistency, and saves time in the master. 

      The bottom line is the is enough tolerance to accommodate a wide range of styles with
respectable scores. 

      Tolerance in the midrange is a cent, becomes 3 cents, and in the extream range becomes 6 cents. The multipliers for error marks range from 3 in the mid, so 6 errors is 18%, to one  in 
The  extremes, so 6 errors is 6%.   Current master tuning protocol, even with some room 
For small variation, does produce masters that work to earmark errors outside these tolerances.
So it functions. I don't think I have heard a  temperament error that did not have a wolf 4th or 5th.
.9 cent either way is a 1.8 cent window.......and variations up and down 1.8 cents  can get 100% 
And yet be a rather "interesting" temperament. The masters function.

       For your experiment I much prefer the verituner data first, to comparing aural tunings first.

I tried to explain to R.N. that two exam teams for 2 days is 48 man hours. I always prescreening
Candidates before booking a test to make sure I'm not wasting people's time. This will be like 
Prescreening before booking a team. Except, with lots of real data.  If someone is motivated to 
Prove the proven changes on inharmonisity do effect aura tuning, that assumption I think is a very very safe assumption, but that assumption can be tested afterwards if we wish. First I wantto know if the harmonic content of the tone actually does change seasonally, and by how much, 
And is there a pattern to the type of piano style, bearing, structure that changes more...
The implications for tuners are large in my mind, especially to those of us using saved concert tunings for broadcast standard work on concert stages. 

Ok.......got to visit my shop, all this thinning is facilitating procrastination.......

                                                                          Dave Renaud



 


                       





Sent from my iPad

On 2012-05-18, at 9:28 AM, Ron Koval <drwoodwind at hotmail.com> wrote:

> 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
> 
> 
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