ETD question re: unisons

Robert Moffatt moffattr@cadvision.com
Thu, 15 Feb 2001 20:51:02 -0700


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Murray,

"Mr. Centre"??? You haven't taken to naming the strings?? =
Pullllleeeeeeeeze!
This is not like you. Too much sesame street perhaps? Sorry......just =
noticed
it wasn't you but an American cousin. Had me scared though. ;~\

Best,
Bob
----- Original Message -----=20
From: Murray Seminuk <seminukm@cadvision.com>

Subject: Re: ETD question re: unisons


> Hi Terry
>Which string do you tune first after Mr. Centre? I usually tune the =
left string
> first and then the centre next.>=20
>Regards
> Murray

> ----- Original Message -----
> From: "Farrell" <mfarrel2@tampabay.rr.com>
> To: <pianotech@ptg.org>
> Sent: Thursday, February 15, 2001 5:20 AM
> Subject: Re: ETD question re: unisons
>=20
>=20
> > Just to add to what folks observe. I routinely observe this =
phenomena. I
> > tune with my SAT, use two mutes and tune my unisons as I go. I kinda =
like
> > that because I can easily observe my center string pitch to make =
sure it
> is
> > stable. I tune Mr. center to the SAT, and then pull in my first =
unison.
> > Often in that killer octave area I see the whole thing drop a tad on =
the
> SAT
> > (go flat) and I think, hmmmm, did my center string drop or did this =
funky
> > thing occur? I move my mute so that only the center string sounds =
and
> > Walla - right back to pitch! This happens often. It sure seems real =
to me.
> > And it definitely varies from note to note. Some notes will have no
> change,
> > some a tiny little bit, and some a frustrating amount.
> >
> > Terry Farrell
> > Piano Tuning & Service
> > Tampa, Florida
> > mfarrel2@tampabay.rr.com
> >
> > ----- Original Message -----
> > From: "Murray Seminuk" <seminukm@cadvision.com>
> > To: <pianotech@ptg.org>
> > Sent: Thursday, February 15, 2001 12:31 AM
> > Subject: Re: ETD question re: unisons
> >
> >
> > > Hi Roger
> > > If  you can audibly here that the note is out of tune with the =
octave
> > after
> > > all these attempts at tuning the unisons,then the note did not =
stay in
> > tune
> > > period.If the full blush of the Rct acts the same as the rotating =
lights
> > on
> > > the Sat ,I think that one does not have to look any futher.The =
unison
> can
> > > only be tuned pure with the ear and good hammer technique.You also
> > mentioned
> > > that this is a newly strung piano. I don't think that this piano =
would
> be
> > > very stable yet to do a test like this and produce any kind of =
results
> to
> > > make any reliable assements.Keep on  testing.
> > > Regards
> > > Murray
> > >
> > > ----- Original Message -----
> > > From: "jolly roger" <baldyam@sk.sympatico.ca>
> > > To: <pianotech@ptg.org>
> > > Sent: Wednesday, February 14, 2001 9:37 PM
> > > Subject: Re: ETD question re: unisons
> > >
> > >
> > > > Hi Muray,
> > > >                The test was done on a newly strung and hammered =
piano,
> > > > regulation set with very close letoff. etc.    Each string was =
sampled
> > 10
> > > > times on the spectrum analyser to ensure the partials on each =
string
> > were
> > > > close. Also verified by ear. Each string was tuned several times =
for
> > full
> > > > blush on RCT, .01cent.  The test was done with back and front =
duplex
> > > scales
> > > > muted.
> > > > The piano was a really nice Steinway O.  But I have have had =
similar
> > > > results from my SD10.
> > > > Several notes were done in this manner each showed a drop of 0.2 =
- 0.3
> > > cents.
> > > > And yes you can just hear the shift when checking the octave. .3 =
cents
> > is
> > > > very audible within the unison
> > > > To do this test all string temination points have to be in good
> > condition.
> > > > Ron is slowly winning me over, re a connection to either =
impedence, or
> > the
> > > > reverse, reactance.
> > > > Some serious study of the principals of reciprocity is badly =
needed
> > before
> > > > we can begin to start to understand what is going on.
> > > > Traditional piano thinking has been to look at the effect of =
loading
> > with
> > > > respect to the impedence of the board.  Mechanical reactance (I
> think )
> > > > will be looking at the boards effect on the strings.
> > > > They are not nessesarily the same.
> > > > The subject is so complex that it would make a great PhD =
project.
> > > > Good to hear from you.
> > > > roger
> > > >
> > > >
> > > > At 08:26 PM 2/14/01 -0700, you wrote:
> > > > >Hi Roger
> > > > >I'm really on a roll tonight , this is my 3rd reply.Correct me =
if I'm
> > > wrong
> > > > >,but are you saying that you tune each string a number of times =
with
> > the
> > > > >RCT,then take a reading of the three together and have a pitch =
drop
> of
> > .3
> > > > >cents.I have been using a Sat for a number of year sand I find =
that I
> > > cannot
> > > > >always use the lights to tune a unison.I do not have a RCT to =
do a
> real
> > > > >comparison but I find that when the lights stop there still is =
a
> > "window
> > > ''
> > > > >to tune within.With my SAT a difference of .3 cents would be
> noticable
> > to
> > > > >the ear.I would wonder if all that has happened is that one of =
the
> > > strings
> > > > >is not in unison.
> > > > >Regards
> > > > >Murray
> > > > >----- Original Message -----
> > > > >From: "jolly roger" <baldyam@sk.sympatico.ca>
> > > > >To: <pianotech@ptg.org>
> > > > >Sent: Wednesday, February 14, 2001 9:27 AM
> > > > >Subject: Re: ETD question re: unisons
> > > > >
> > > > >
> > > > >> Hi Howard,
> > > > >>                  Yes it is easy to confirm.  The test that I =
have
> > done
> > > > >with
> > > > >> a RCT show about a 0.3 cent drop in octave 5/6. The test was
> > performed
> > > by
> > > > >> tuning each string individually several times, to over come =
the
> > > > >> interaction. then the net 3 string unison was measured.
> > > > >> The effect is known as string coupling.
> > > > >> My own theory is that. as all strings start to increase the =
amount
> of
> > > > >> energy into the bridge, the board is moving through a greater
> > > excussion,
> > > > >> and hence dropping the frequency a tad.
> > > > >> Now I've been out to lunch before, and I could be off base on =
this
> > one.
> > > > >> Regards Roger
> > > > >>
> > > > >>
> > > > >> At 10:47 AM 2/14/01 -0500, you wrote:
> > > > >> >Hi everyone,
> > > > >> >
> > > > >> >Since I know nothing about ETD's my question might be naive.
> > > Nevertheless
> > > > >> >here goes: I believe that Virgil's assertion that a 3 string
> unison
> > is
> > > > >> >flatter than each of the single strings heard singly, is a =
bit
> > > > >questionable
> > > > >> >or should I say not fully accepted. Wouldn't it be easy and
> > conclusive
> > > to
> > > > >> >check this thesis by using an ETD to measure this? Thanks!
> > > > >> >
> > > > >> >
> > > > >> >Howard S. Rosen, RPT
> > > > >> >7262 Angel Falls Ct.
> > > > >> >Boynton Beach, Fl  33437
> > > > >> >
> > > > >> >hsrosen@gate.net
> > > > >> >
> > > > >>
> > > > >>
> > > > >
> > > >
> > > >
> > >
> > >
> >
> >
>=20
>=20

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