Octave partials

[tune4u@earthlink.net]

For many, many pianos 6:3 makes a nice bass without the beat that would
occur at the 6:3 junction. That's what it means to tune a specific type of
octave, i.e., no beat AT THAT PARTICULAR MEETING OF PARTIALS. The 6:3 is a
little wider than the 4:2 which is Wider than a 4:1 which is wider than a
2:1. GENERALLY most pianos work best with--or at least it's a good starting
point--4:2's (or nearly) in the center, 6:3's below the temperament
(starting at or near the tenor/bass break with a smooth transition between
them), and more like 4:1's going up in the treble. This is what TuneLab
defaults to, for example.

It's all based on the inharmonicity of the strings which is directly a
product of the stiffness of the strings, the length of the strings, the
quality and condition of the strings, and the workability(?) of the maker's
scale design (string lengths and tensions, primarily).

Other factors include striking point of hammer, condition of hammer,
soundboard responsiveness, condition of bridges, etc., which can all serve
to reinforce objectionable partials, introduce partials that have no
business being in a given string, or kill the expected tuning partials
(especially in the low bass), or mess up the tone of the string by allowing
the "wrong" partials to predominate.

Which doesn't even touch on false beats muddling up what we hear.

See why the ear has to be the final judge, even with $1,600 gadgets?

Sometimes the ETD wins because it can "hear" better than we are yet trained
to hear (or maybe we god uh code in ar noz an ar ears ar sduvy that day).
Some times the ear wins because we think it just sounds better than the
flashing lights or radar detector moving bars are telling us.

Remember, we have the power. If your ETD gets uppity, just pull the battery
out of that sucker.

A fun little illustrative fact: On wee pianos, sometimes the fundamental
pitch of a note dies instantly because the soundboard, etc., simply won't
sustain it. We "think" we continue to hear it because we hear a series of
overtones (partials) and "infer" the fundamental. Want proof, set up your
ETD to tune using the fundamental partial of a very low note on a little
teeny spinet or premature baby grand. The device will say: "I don't hear
nuttin'"

So, you see, your question could only be thoroughly answered in some very
thick textbooks. And there would be considerable debate, even among the
experts. 

There is a great deal of science involved, including things that don't
behave according to the rules very well (many factors to control or account
for) and MUCH of it is subjective and experiential and, frankly, matters of
taste and tolerance.

Kinda overwhelming. 

What was the question, again?

Hey, old pros and experts--if I got any of this wrong please correct me and
all who read this!

Alan Barnard
Salem, MO

-----Original Message-----
From: pianotech-bounces@ptg.org [mailto:pianotech-bounces@ptg.org] On Behalf
Of David West
Sent: Tuesday, May 27, 2003 8:52 PM
To: pianotech@ptg.org
Subject: Octave partials

Hi List,
I am currently a student of the trade, and enjoy reading the information
and debates posted on this forum!!
I have a question regarding Octave Partials, and will try to keep this
short
I know that in a 4:2 octave, you tune the 4th partial of the lower note
to the 2nd partial of the upper note as well as with a 6:3 octave, and
so on.  So my question is, for example when tuning an F octave what is
the distinction between 4:2, and say a 6:3 octave tuning?
I have searched the archives, and reviewed my potter course manual, and
still a little confused!  I plan on purchasing RCT in the next couple of
days, for my dell axim to assist in the progress of my aural tuning.
Sorry to post such a basic question, and hope no one gets to
perturbed!!!

Thanks in advance!!
David West
Roscoe , IL.

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