[pianotech] Possible adaptation for the Tuning Exam

[Encore Pianos]

Duane:

No one has put it simply enough yet:   You can't tune an acceptable
temperament or anything else in the piano using a pitch pipe or an octave
set of tuning forks because of I-N-H-A-R-M-O-N-I-C-I-T-Y, Duane.  That's
what the others are talking about when they use the word stretch.  Did you
know that your ETD measures inharmonicity and calculates a tuning with
algorithms based on those measurements?  That's why the ETD tuning can sound
good, and why a skilled aural tuning can sound good.  It's also the reason
why when you are at a church you cannot tune a piano to an organ note for
note.  If you do not have a good working understanding of inharmonicity,
here's a place to start, Wikopedia.
http://en.wikipedia.org/wiki/Inharmonicity  There's a lot more to it than
that regarding pianos, but you really need to have at least a basic
understanding of inharmonicity before you can begin to hold up your half of
an intelligent conversation with others on this list concerning how a piano
is tuned.  If you do not know about inharmonicity or understand it, you will
not understand why the choices that are made by man or machine in tuning are
being made.  

I'll even do some of the work for you, from Wikopedia:

Inharmonicity leads to stretched tuning

When pianos are tuned by ear by technicians called piano tuners, the
technician listens for the sound of "beating" when two notes are played
together, and tunes to the point that minimizes roughness between tones.
Piano tuners must deal with the inharmonicity of piano strings, which is
present in different amounts in all of the ranges of the instrument, but
especially in the bass and high treble registers. The result is that octaves
are tuned slightly wider than the harmonic 2:1 ratio. The exact amount
octaves are stretched in a piano tuning varies from piano to piano and even
from register to register within a single piano-depending on the exact
inharmonicity of the strings involved.

Because of the problem of inharmonicity, electronic piano tuning devices
used by some piano technicians are not designed to tune according to a
simple harmonic series. Rather, the devices use various means to duplicate
the stretched octaves and other adjustments a technician makes by ear. The
most sophisticated devices allow a technician to make custom inharmonicity
measurements--simultaneously considering all partials for pitch and volume
to determine the most appropriate stretch to employ for a given instrument.
Some include an option to simply record a tuning that a technician has
completed by ear; the technician can then duplicate that tuning on the same
piano (or others of similar make and model) more easily and quickly.

The issues surrounding setting the stretch by ear vs machine have not been
settled, machines are better at deriving the absolute placement of semitones
within a given chromatic scale, whereas non-machine tuners prefer to adjust
these locations preferentially due to their temptation to make intervals
more sonorous. The result is that pianos tuned by ear and immediately
checked with a machine tend to vary from one degree to another from the
purely theoretical semitone (mathematically the 12th root of two) due to
human error and perception. (If pleasing the ear is the goal of an aural
tuning, then pleasing the math is the goal of a machine tuning.) This is
thought to be due to the fact that strings can vary somewhat from note to
note and even from neighbors within a unison. This non-linearity is
different from true falseness where a string creates false harmonics and is
more akin to minor variations in string thickness, string sounding length or
minor bridge inconsistencies.

Piano tuning is a compromise-both in terms of choosing a temperament to
minimize out-of-tuneness in the intervals and chords that will be played,
and in terms of dealing with inharmonicity. For more information, see Piano
acoustics and Piano tuning.

Another factor that can cause problems is the presence of rust on the
strings or dirt in the windings.[5] These factors can slightly raise the
frequency of the higher modes, resulting in more inharmonicity.

While others may offer somewhat differing interpretations of what is said
here, it is at least simple and straightforward to get you into the ballpark
of what is going on.  

Will Truitt

-----Original Message-----
From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf
Of Paul Williams
Sent: Sunday, November 11, 2012 4:47 PM
To: pianotech at ptg.org
Subject: Re: [pianotech] Possible adaptation for the Tuning Exam

True; true A 440 is the way to go  If you can't set A-440 first, then you
can't take the test period!
Paul

On 11/11/12 3:07 PM, "Jon Page" <jonpage at comcast.net> wrote:

>If you can't hear beats, you can't use a tuning fork. You have to hear 
>the beats to 'zero' it in.
>
>Or is it that you can hears the beats on unisons and octaves but the 
>intervals elude you. Take the time, listen closer. Have a tuner guide 
>you as to what to listen to.
>
>A pitch pipe's pitch will vary by the degree of air flow. A harder blow 
>will create a higher pitch. Temperature would be another variable.
>
>I saw one tuner strike the fork on his knee and then hold the end 
>between his teeth, this allowed him to play the note and tune 
>simultaneously. It worked for him but it looked really weird.
>
>To set your A or C from a fork, tune the corresponding note to the fork 
>and then tune the note an octave lower to that note. Check the lower 
>note with the fork, listen to the beat rate and adjust lower note to 
>the octave to be the same beat rate sharp or flat. Check lower note 
>against fork. If off, tune the upper note to the new beat rate. Check 
>upper note against fork. If necessary, adjust the lower note to the 
>beat rate. Once you have established the lower note pure with the fork, 
>tune the upper note to it. Proceed with your temperament.
>
>But if you can't discern beats, stick with an ETD.
>
>--
>Regards,
>
>Jon Page
>
>