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See Comments below, regards, Bernhard Stopper<br>
<br>
Jason Kanter wrote:
<blockquote
cite="mid:c85b54f50708220940p45157e20r38d5accd56fad72b@mail.gmail.com"
type="cite">
<div>Double octave, yes. But within this, check all the twelfths --
they should be as close to pure, beatless as possible and this will
guarantee the right amount of stretch. </div>
</blockquote>
agree<br>
<blockquote
cite="mid:c85b54f50708220940p45157e20r38d5accd56fad72b@mail.gmail.com"
type="cite">
<div>The test for a perfect 12th is a sixth below the lower note.
That is: to test C4-G5, use Eb3 against the C4 (a sixth that beats at
the frequency of G5) and Eb against G5 - should beat the same. This
will almost always give you an octave stretch that is the sweet spot
between 4:2 and 6:3.Note - mathematically perfect ET twelfths in a
world without inharmonicity would be narrow. </div>
</blockquote>
correct for standard ET temperament<br>
<blockquote
cite="mid:c85b54f50708220940p45157e20r38d5accd56fad72b@mail.gmail.com"
type="cite">
<div>Inharmonicity stretches them. </div>
</blockquote>
not very correct.<br>
inharmonicity stretches <b>everything, still keeping the problem of
the pythagorean comma.</b><br>
tuning twelfths pure an ET, is the result of a <b>completely different</b>
ET temperament, dividing the pythagorean comma to the octaves.<br>
See more about my work on this at <a class="moz-txt-link-freetext" href="http://www.stopper-scale.com">http://www.stopper-scale.com</a><br>
<br>
<blockquote
cite="mid:c85b54f50708220940p45157e20r38d5accd56fad72b@mail.gmail.com"
type="cite">
<div>The spot of the perfect 12th turns out to be a great choice for
the stretch because the 3rd partial is usually very strong.Perfect
twelfths are also an excellent test up into the high treble.<br>
</div>
</blockquote>
<blockquote
cite="mid:c85b54f50708220940p45157e20r38d5accd56fad72b@mail.gmail.com"
type="cite">
<div><span class="gmail_quote">On 8/22/07, <b
class="gmail_sendername">John Formsma</b> <<a moz-do-not-send="true"
href="mailto:formsma@gmail.com">formsma@gmail.com</a>> wrote:</span>
<blockquote class="gmail_quote"
style="border-left: 1px solid rgb(204, 204, 204); margin: 0px 0px 0px 0.8ex; padding-left: 1ex;">Comments
interspersed.<br>
<br>
On 8/21/07, Matthew Todd <<a moz-do-not-send="true"
href="mailto:toddpianoworks@yahoo.com">toddpianoworks@yahoo.com
</a>> wrote:<br>
> I have been really, really studying tonight.<br>
<br>
Good! You will eventually get it if you keep studying the right stuff<br>
and apply yourself. I promise.<br>
<br>
> Can someone please explain the system they use to tune 2:1, 4:2
and 6:3
<br>
> octaves. I am so close to grasping this concept, but I think I
need another<br>
> tech to explain it to me besides Reblitz.<br>
<br>
Get someone else besides Reblitz. As was mentioned, Baldassin's On<br>
Pitch, the newly revised version, and the PTG Tuning Exam Source Book
<br>
were great for helping me understand all this.<br>
<br>
> In the octave interval, if I were to tune a 4:2, the fourth
partial of the<br>
> lower note theoretically has the same frequency as the 2nd partial
of the<br>
> upper note. Do those partials normally dominate each octave? How
can I<br>
> tell whether to tune a 4:2 or a 6:3?<br>
<br>
Yes, you have a dominant partial pair. Which is why you "normally"<br>
tune certain octave sizes in certain places in the piano. The
<br>
Baldassin book has a chart that tells which octave size generally fits<br>
best.<br>
<br>
However, you must get the best fit for each piano. You can't just<br>
begin by tuning a 4:2 plus a little bit in the A3-A4 octave in every
<br>
piano, and expect it to be the best. Some pianos will require in<br>
between a 2:1 and 4:2, and some pianos might allow for 6:3.<br>
<br>
To help you know what octaves will work with the piano, I find it<br>
immensely helpful to start by working within a double octave. You tune
<br>
A3-A4 first, then tune A2 from A3. This will help you establish the<br>
correct octave width b/c you are using two octaves rather than one.<br>
(Otherwise, if you begin with a A3-A4 octave that is too wide, you<br>
will end up with bass and treble octaves that beat too much. Working
<br>
with a double octave prevents this.)<br>
<br>
What I do is this: Tune A4, then A3. Make it sound the best (you can<br>
change it later). Check to make sure it's close to a 4:2 octave with<br>
the M3-M10 test (because usually that fits most pianos well). Then
<br>
tune A2 from A3, and make it a 6:3 octave using the m3-M6 test. Then<br>
you want to use F2 with A2, A3, and A4 to see if those octaves will<br>
work for that piano.<br>
<br>
You want to first make sure that A2-A4 is not more than 1 bps. This
<br>
is *very* important. Play F2-A2, then compare it with F2-A4. (Listen<br>
at A4.)<br>
<br>
Now use F2 to check A4 and A3. F2-A4 will probably be a tiny bit<br>
faster than F2-A3. And F2-A3 will probably be a tiny bit faster than
<br>
F2-A2. If you have correctly set these octaves, the tuning will fit<br>
that piano very well. There may be some strings in lesser pianos that<br>
don't fit well, but they will be minimized if you get octaves right
<br>
from the first. If you do this on a well-scaled piano, you will be<br>
astonished at how good it can sound when you're done. Octaves<br>
complement each other, and it is just delightful.<br>
<br>
Clear as mud? Probably. <Grin> Get the books, do the requisite
<br>
head-scratching and pulling out. You'll get it sooner or later if you<br>
don't give up.<br>
<br>
You will also find there are multiple checks for octaves. The M3-M10<br>
is a check for a 4:2 octave. But also another good one is the
<br>
"shared" P4/P5 test. Say you're checking A3-A4 to see if it's 4:2. If<br>
A3-D4 beats the same as D4-A4, it's a 4:2. HOWEVER, the 4th must be<br>
expanded, and the 5th must be contracted for this test to be valid.
<br>
So, it would go like this: Expand D4 to get a 4th beating to whatever<br>
you can hear well. Then check D4-A4 to see if it's the same. If it's<br>
the same, it's a 4:2. If it's faster, you have an octave smaller than
<br>
4:2. If it's slower, you have an octave larger than 4:2.<br>
<br>
I like to use this test because it's relatively easy to hear. I find<br>
it tricky to know if the M3-M10 beats are the same because of<br>
competing higher partials that can fool the ear.
<br>
<br>
Wish we were able to sit down at a piano while explaining this. It<br>
would be much more understandable.<br>
<br>
JF<br>
</blockquote>
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-- <br>
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jason's cell 425 830 1561 </blockquote>
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