1/2 cent difference on unison

[Frank Weston]

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