1/2 cent difference on unison

[Jim Coleman, Sr.]

Hi Frank:

As a result of that written below, do you then tune your first single string
of an octave approx. 1/2 cent sharp in order that the complete unison 
and octave will be in tune as Virgil does?

Jim Coleman, Sr.

On Thu, 29 Jan 1998, Frank Weston wrote:

> Those tuning with SAT's may not easily observe this phenomenon, but I use
> TuneLab on a PC and the effect is quite apparent.  If I tune the first
> string of a unison to the TuneLab phase display, causing the display to be
> stopped, then tune the remaining stings in the unison and observe the phase
> display, it indicates a pitch about 1/2 cent flat (maybe somewhat  less)
> for the whole unison.  This result caused me quite a bit of consternation
> at first, but after lots of checking by ear and VTD, I found it to be a
> common artifact present in any good tuning.
> 
> Frank Weston
> 
> ----------
> > From: Don <drose@dlcwest.com>
> > To: pianotech@ptg.org
> > Subject: Re:1/2 cent difference on unison
> > Date: Thursday, January 29, 1998 4:26 AM
> > 
> > Hi Bill,
> > 
> > This is very interesting!
> > 
> > >  It has been well demonstrated that a
> > >properly tuned unison will read about 1/2 cent flat of a single string. 
> This
> > >presents a problem both in aural and electronic tuning.
> > 
> > Who has demonstrated this and how? There has been some discussion of this
> > before on the list. But only Jim Coleman has *posted* his results. I had
> > hoped that another technician would try to duplicate his results!
> > Regards,
> > Don Rose, B.Mus., A.M.U.S., A.MUS., R.M.T., R.P.T.
> > "Tuner for the Centre of the Arts"
> > drose@dlcwest.com
> > 3004 Grant Rd.
> > REGINA, SK
> > S4S 5G7
> > 306-352-3620 or 1-888-29t-uner
>