Beat Rates in stretching

[Richard Moody]

The stretching of octaves beyond the natural stretch of
inharmonicity is a matter of taste and also what the piano will
take.  If you are talking about a performance tuning, then you
have to pretty much take the piano where it is at.  If you have to
do a pitch raise (more than 20 notes) to a performance piano then
you are looking at two tunings.  Pitch raises always require
stretching in the upper octaves because the tendency there is to
"pull down".    You want to err on the sharp side simply to avoid
erring on the flat side when the tension of the raise has
"settled".  And how long does this settling take?   Again it
depends on the piano but hopefully you get to check it after two
hours.
    As far as the sounds of "stretched octaves" I agree with Don
below. To me right on octaves (as verified by the
10th test.) sound the best.   This may reflect that I like to hear
the double octave "right on" as verified by the double tenth test.
This is what I
like best when I play and hear the piano being played.   I am not
a pianist as far as playing level goes, but Don is a fantastic
(among tuners at least) pianist, so his preferences should carry a
lot more weight.
    An interesting experience with octave stretching occurred at
the Chicago convention.  One night in a hallway outside the
exhibition hall unfettered by security, sat the Shigeru Concert
Grand.  Since there were a couple of people by it I stopped by to
see what was going on.  When it came to checking the tuning it was
sharp in the treble up to 2 bps even over the hum of lighting and
air-conditioning.    Maybe it was just raised to pitch I thought.
Next day after the concert some techs were checking it out and
then  the octaves were pretty much dead on as far as could be
discerned through the noise of the crowd.  At the reception Shinji
Kurisu, the Kawai tech was there but I didn't think to ask
him about the sharp treble the night before.   The piano was
awesome and he was taking well deserved compliments on that.
    The final factor in stretched octaves that must be considered
is that the piano itself shifts in tuning in reaction to changes
in humidity
and temperature when the theater fills up.   If people
were to record a tuning on a ETD right after the final touch up,
and then record the tuning at intermission and then record the
tuning right after the end of performance, the printed readouts
might give us all a big surprise.
     So it (stretching the octaves) all goes back to the way I was
trained,
"tune the octaves sharp as you can without breaking the rules".
The words of my teachers are still in my ears like yesterday,
"this 10th is too slow, this one is a little fast, this one is
just about right".  They did that for all intervals esp. the 3rds
and 5ths.  For the 5ths they said, "this is a little to pure, this
one is tempered too much."    Lately I have been getting 5ths that
they would have said, "this is a little too pure".  I can just
hear Jim Coleman over my shoulder, "You never paid attention to
your fourths,  you think this 5th sounds Ok, what about this 4th?"
And that is how I got purer 5ths.
     I don't think my temperaments were sloppy at least after the
first 3 years but I am  pleased to say they are better after the
last 23 years.  Is improvement possible?   I hope so.   This
conversation about stretched octaves is an example of quest for
improvement. It is tough to tune stretched octaves, it takes time
and effort and then when you get a degree of proficiency you have
to determine if it does sound better. Or at least make sure it
doesn't sound worse.
    For aural tuners it is much easier to tune octaves beatless.
To aurally tune an octave say .5 bps sharp,  the most expedient
way is to determine if you have it by listening to the 10ths.   Of
course the time it takes to play and listen to the beats and then
adjust if necessary adds to the effort of tuning.  When I tune
octaves beatless there is a certain sound I try to attain that
comes from listening to just that octave, as I pull through and lo
wer back down and pull through again, all the while listening to
when there are no beats.   If I wanted to "stretch" that octave
then the sound will be different from what I have practiced and
trained for years. That is not to say I can't do it.  If I want an
octave stretched by .5 bps I would have to hear the 10th beat
faster by a certain amount than the 3rd.  But then the final say
would be in the 10th rather than the octave.  When you tune pure
octaves the 3rds and 10th beat the same or close as possible.
Also when checking.  with pure octaves you can use the double
octave test, with for example   A3--A4--A5 or simply A3-- --A5.
Or course both tests should be listened to in the end.   With
stretched octaves I don't know how this would sound, so I go with
A3-- --A5 beatless, or if not perfect a little on the sharp side
as proved by F3-- --A5.

--- ric   (the i stands for inharmonicity takes care of it all)



----- Original Message -----
From: Donald Mannino <donmannino@attbi.com>
To: <pianotech@ptg.org>
Sent: Monday, August 05, 2002 9:39 PM
Subject: Re: Beat Rates in music


> Richard,
>
> I have taught a technical seminar on this very subject, called
"The Sound of your Tuning."  I tune 2 matched grand pianos with
widely different stretches, and demonstrate the affect this has on
the sound of the tuning overall.
>
> It is my contention that the octave stretch style used has a
much larger affect on the sound of the piano than the often subtle
differences between temperaments.  The difference between  sloppy
equal temperament and a careful equal temperament is rather hard
to hear when playing music, but the difference between wide
octaves and narrow ones is quite noticeable.
>
> I do use different octave tunings depending on the situation and
use and, to some degree, the tastes of the pianist.  I tune for
some pianists who like a more aggressive sound from the piano that
a wide tuning gives, while I have had others specifically
complement me for the "warm" sound of my tuning, after having done
my preferred narrower tuning style.
>
> Don Mannino RPT
>
>
>