P12 in Tunelab Pro

[Richard Brekne]

Hi Jason.

Great effort ... once again ! I will try and take a good solid look at 
this during the comming week before traveling to Japan. I only have the 
unregistered version of Pro, so I may have some hindrences. But I'll see 
how it works out and get back to you all. It would be great if you've 
worked this out. Given B.Stoppers and Dr. Colemans endorsement for the 
approach I think it should be included as part of the standard tuning 
setups available on ETDs.

Cheers, and thanks Jason
RicB

jason kanter wrote:

> I've worked out the method of tuning the Brekne Perfect 12th tuning 
> using Tunelab Pro. (As we know, Ric uses Tunelab 97 for this, and his 
> method does not work in TuneLab Pro. Tunelab 97 crashes on my XP 
> machine, and TL Pro has additional features that I like very much, so 
> I've worked out this method.) Haven't tuned it yet.
> I would very much appreciate, Ric, if you can verify that this 
> duplicates the lovely tuning that you achieve. It should be precisely 
> accurate from D3 through C8. The method for the bass is uncertain at 
> the moment.
> 1. Take inharmonicity measurements as normal.
> 2. Go to the Partials window (press P) and set all partials to 1. Then 
> set the following partials to 3: D3, B4, F6.
> 3. Click OK and now press T for the tuning curve screen. Click the 
> button to allow manual adjustment of all 4 aspects of the tuning 
> curve. Set both bass and treble octave types to 4:1. Now press Z to 
> zoom out to be able to see the entire curve.
> 4. You now need to make four precise adjustments as follows (it takes 
> several passes to get these exact):
> a. Toggle the H and Y keys to set the deviation for A0 to exactly zero 
> (lower pane).
> b. Toggle the J and U keys to set the D3 exactly at 0.0. (This makes 
> the perfect twelfth with A4).
> c. Read the offsets of B4 and F#6 (somewhere between 5 and 10 cents). 
> Toggle the K and I keys to make these two offsets match exactly.
> d. Read the offsets of F6 and C8 (generally 30-35 cents). Toggle the O 
> and L keys to make these two offsets match exactly.
> The deviation lines (which are displaying deviations in the 4:1 
> octaves) will not be straight, because we are favoring twelfths over 
> double octaves. But the deviation line does stay within +1 to -1.
> 5. When done, return to the Partials screen to change them to your 
> preferred partials for executing the tuning (e.g. use 6 from A0 to E1, 
> etc.)
> As Ric has pointed out, the bass may feel a bit shallow. It is 
> possible to do the exact same procedure using 6:3 in the bass, except 
> that D3 winds up a few cents south of zero to accommodate that greater 
> stretch in the bass. (Also the bass deviation curve is more 
> distorted). As I have not yet tuned this, I anticipate a strong need 
> to verify the bass aurally and determine what works best. It will be 
> nice when Bob Scott adds 3:1, 6:2 and 9:3 to the tuning curve menus.
> Feedback most welcome.
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> jason kanter • piano tuning/regulation/repair
> bellevue, wa • 425 562 4127 • cell 425 831 1561
> orcas island • 360 376 2799