Your guitar or mandolin might already be capable of 11 or 13TET!

THE STORY:
----------

Today a friend of mine complained to me that his Quattro didn't sound quite
right when he played it with other instruments. I checked the intonation at
the octave, and found it to be reasonably close. Then I counted the number
of frets to the octave. 11 - WOW! He is probably the proud owner of the
worlds only 11 tone equal tempered Quattro! He seemed confused by my
congratulations.

This unique Quattro neck was probably the result of building two instruments
of slightly different scale lengths, drinking too much, and mixing up the
fretboards. I wonder if there's a sibling 13tet Quattro lurking around
somewhere?

THE IDEA:
---------

On acoustic guitars or mandolins with moveable bridges (usually guitars with
tailpieces and a wooden bridge):

* Slide the bridge toward the nut until the octave harmonic and the 11th
fret play in tune with one another on the first string.

* Keeping that end of the bridge in place, adjust the 6th string side so
that it's octave plays in tune with it's 11th fret.

Presto! 11tet. You can tune the octave harmonic to any fret from about the
9th, to the 15th without running into the soundhole or getting too close to
the tailpiece. Even on a regular acoustic guitar, you can make a surrogate
bridge to sit in front of the real one. Careful not to scratch the finish
though!

It's free, requires no permanent modification to your instrument, and no
tools other than your hands and ears.

Have fun experimenting!

---
Glen Peterson
30 Elm Street North Andover, MA 01845
(978) 975-1527
http://www.OrganicDesign.org/Glen/Instruments

> [Glen Peterson, TD 305.12]
>
> On acoustic guitars or mandolins with moveable bridges (usually
> guitars with tailpieces and a wooden bridge):
>
> * Slide the bridge toward the nut until the octave harmonic
> and the 11th fret play in tune with one another on the first
> string.
>
> * Keeping that end of the bridge in place, adjust the 6th string
> side so that it's octave plays in tune with it's 11th fret.
>
> Presto! 11tet. You can tune the octave harmonic to any fret
> from about the 9th, to the 15th without running into the
> soundhole or getting too close to the tailpiece. Even on a
> regular acoustic guitar, you can make a surrogate bridge to
> sit in front of the real one. Careful not to scratch the finish
> though!
>
> It's free, requires no permanent modification to your instrument,
> and no tools other than your hands and ears.

At the Sonic Arts Gallery, one of the guitars we have that was
re-fretted by Ivor Darreg is nominally in 18-tET, but has a
moveable bridge so that Ivor could make this guitar a pseudo-
17- or 19-tET instrument, in the same way that Glen describes.

Ivor experimented with *all* the ETs from approximately 5-tET
to 53-tET, and was particularly interested in 17-tET and 19-tET.

This was a cheap and easy way to have one guitar come close to
playing both of those ETs, and at the same time, to give
18-tET exactly.

-monz

Joseph L. Monzo Philadelphia monz@juno.com
http://www.ixpres.com/interval/monzo/homepage.html
|"...I had broken thru the lattice barrier..."|
| - Erv Wilson |
--------------------------------------------------

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