[CAUT] ghost tuning

[David Love]

When I do ghosting I do something similar though I tend to hit the upper
notes at the same time and then tune the lower note until I find a place
where everything is the quietest.  For example, holding down C1/C2 strike
C3, G3, C4 staccato and listen as you tune C1.  You'll find a place where
the three coincident partials will strike a balance and everything gets
quiet.  You can choose any group depending on your goal.  

 

David Love

www.davidlovepianos.com

 

From: caut-bounces at ptg.org [mailto:caut-bounces at ptg.org] On Behalf Of Fred
Sturm
Sent: Wednesday, May 06, 2009 4:32 PM
To: caut at ptg.org
Subject: Re: [CAUT] ghost tuning

 

On May 5, 2009, at 9:54 PM, David Love wrote:





If you're testing a 6:3 octave (for example) then you would hold down C1 and
C2 so that the dampers are lifted off the strings but the hammers don't
actually strike the strings.  Hold down mute, it's called, and then strike
(not hold down), strike and let go of the G3.

 

            I like to do a variant of this: play the octave softly, then
strike the ghost tone in a staccato blow a tiny moment later. Getting the
strings of the octave moving a bit to start with can make it easier to hear
the partial beat. I like to accentuate a number of partial matches: with
C1/C2 sounding, play C3 (4:2), G3 (6:3), C4 (8:4), E4 (10:5), G4 (12:6), A#
4 (14:7) (each of these separately).  Listen to the difference in beat
rates, it will tell you a lot about the inharmonicity curves of the two
notes of the octave (how they line up or don't line up), and give a good
idea of where to place that octave. Slightly wide 6:3 is a good default
beginning place. If going up the ladder to 8:4 or higher isn't that far
away, then a wider octave might be appropriate. Doing the whole ladder is
also good ear training, and tells you a lot about what the "whole sound" of
the octave will be. When those beat rates vary a lot, the "whole sound" will
be pretty chaotic, and you have found out why.

            There is another way the term ghosting is used, and that is to
accentuate test intervals. In that case, you would - to check 6:3 of C1/C2 -
hold C1D#1 and strike G3, then hold D#1C2 and strike G3, and compare beat
rates. Sometimes it is hard to hear the partials of the test intervals
clearly, and ghosting can bring them to the fore.

            A caveat: ghosting can also accentuate higher partials. The test
for 6:3 can excite 12:6 as well. The test for 4:2 can excite 8:4 and 12:6.
(The test note being struck has more partials than just its first partial,
so it can excite the equivalents of those partials as well). So you need to
be listening to beats at a specific pitch to get good information. It is
also possible to use the ETD to look at the same information, setting the
ETD for the partial you want to hone in on. This can be cumbersome, though,
for a lot of the partials, depending on the model of ETD and what partial it
is set to listen to in its tuning mode.
Regards,

Fred Sturm

University of New Mexico

fssturm at unm.edu

 

 

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