ETD question re: unisons

Farrell mfarrel2@tampabay.rr.com
Sat, 17 Feb 2001 09:12:29 -0500


Hi Murray. Sorry I have taken so long to respond. Gotta put food on the
table. Comments interspersed below:

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 9:28 PM
Subject: Re: ETD question re: unisons


> Hi Terry
> I too tune my unisons as I go but in that area I only use 1 mute .Which
> string do you tune first after Mr. Centre?

I tune just like you pitch raise with two mutes starting from A0. First
tenor string, two mutes on left and right string - tune center to SAT, leap
frog right mute to right string of next note - tune right string to center,
leap frog left string mute to left string of next note - tune left string to
center, and you are set up to tune center string of next unison with the
SAT.

> I usually tune the left string
> first and then the centre next.At this point if there was a drop in pitch
I
> would think that it was a result of increasing the tension of the same
> complete string as it loops around the hitch pin .This is all relavent to
> the amount of pitch raise of the note as to how mutch it might move.If it
> moves I go back and bring it up.Then I bring the right string in,Moving to
> the next note I am working with the same looped string as the right string
> on the previously tune note and at times I find that bringing it up to
pitch
> can effect it the same way.Carrying on up the scale I always check a fifth
> below the note that I am working on and I find that notes below can and do
> move ever so slightly,so one is always touching up.I attribute this to the
> increase downbearing on the bridge in this very sensitive area.

The above addresses tuning a string where there is some significant change
in pitch. I have come full circle on this issue. The SAT, RCT, whatever ETD
can do a wonderfully accurate job of calculating pitch raise targets. But I
find that your tunings will be 100%+ better if you pitch raise/pitch adjust
first and then tune. Even for a run-of-the-mill Mrs.
Jones-downthestreet-BaldwinAccrosonic-for-Susie-tuning, I like to get the
whole keyboard within two cents of targeted pitches prior to my final tuning
pass. That means even if I do a separate pitch raise of like 25 cents (my
last tuning yesterday), usually they come out nearly perfect, but for some
reason my last one was up to 5 cents sharp over two octaves in the middle.
So I went through that area again real quick to settle it down.

Anyway, concerns about notes next door moving because of the change in pitch
of the string you are currently working on are null and void if you get the
whole piano right on pitch first.

> Dealing with
> shorter and shorter strings also make the margin of error is smaller.After
> going all the way to note 88 I check double and triple octaves
chromatically
> down and again there are notes to touch up. I have read in some previous
> post that the  lights on their  SAT spin up  and then  settle back down to
a
> stop.I have never noticed that with either my SAT11 or 111.

Yes, I see this all the time. Hit a string hard and watch the lights spin
sharp - maybe a lot or maybe a little - then after the first second the
lights will stop spinning (not all strings, but many will do this & some
pianos more than others). Basically, the first second of ring is more sharp
than the following sustain period. I try to be consistent with my key blows
(my medium-blow key depressing device) and measure pitch on a medium blow
when I see this sort of thing occurring.

> I do notice a
> difference in their tuning calculations and I really like the SAT 111 over
> the SAT11.What are your thoughts?

Well, yes I like my SAT III much more than the SAT I (my backup is a SAT I
(#363) with FAC), but mostly because of better battery, smaller size and the
new features - DOB, historical tunings, etc. If I wasn't struggling so much
with the basics of tuning and hammer technique, I might notice more about
the way it calculates tunings. I did not realize there was any significant
difference. I was aware however, that the code for calculating did change a
bit and in fact does change the outcome for a given input. We had a series
of posts several months ago where someone had a question regarding the
output from his three FAC numbers. A bunch of us entered the numbers in our
SATs and got various results. Sanderson's finally cleared all this up by
pointing out that yes, indeed the computer code has been  refined over time.
My SAT I calculates the same tuning for a given set of FAC numbers as my SAT
III. That is because I had my SAT I upgraded about a year ago with all the
latest circuit boards inside, so I also have the newest computer codes in
it.

>
> 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
>
>
> > 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
> > > > >> >
> > > > >>
> > > > >>
> > > > >
> > > >
> > > >
> > >
> > >
> >
> >
>



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