post pitch-raise creep?

[Porritt, David]

David:

 

As Dr. Sanderson has shown from tests he has made that doing
unisons-as-you-go allows for a smaller overpull, and a more stable end
result.  Of course I think pitch raising is one of the big advantages of
using an ETD.  When I was tuning strictly aurally, I couldn't get nearly
as satisfactory a result as I can now using TuneLab Pocket.  

 

dave

 

David M. Porritt

dporritt at smu.edu

________________________________

From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On
Behalf Of David Nereson
Sent: Sunday, July 09, 2006 6:56 AM
To: Pianotech List
Subject: RE: post pitch-raise creep?

 

 

	-----Original Message-----
	From: pianotech-bounces at ptg.org
[mailto:pianotech-bounces at ptg.org]On Behalf Of Farrell
	Sent: Friday, July 07, 2006 6:04 AM
	To: Pianotech List
	Subject: Re: post pitch-raise creep?

	Doesn't sound right. When doing the PR, are you using an ETD?  

	 

	Only to measure the amount it's flat and to tune the initial A4
sharp by 40% of the amount it was flat.  

	 

	 Unisons as you go?  

	 

	No.  All the middle strings, then all the unisons, then the
bass, which sometimes needs very little raising.  I can do it fastest
that way.    

	 

	 41% is very large percentage for overpull. Most ETDs recommend
between 20% and 35%, depending on the area of the scale. 

	 

	And I say that's usually not enough.  If it's 20 cents flat,
half of that (50%) is 10 cents, and a third of that (33%) is about 7
cents.  So I pull A4 halfway in between those numbers, or about 8 1/2
cents sharp, which is roughly 40% of the amount it was flat.  (I notice
in other posts, some tuners use up to 37% in some areas of the piano.)
Then I do the pitch raise, all the octaves, then all the unisons.
Almost every time, A4 ends up right on 440, and the rest of the rough
tuning is very close.   So I go ahead and do the tuning (fine tuning).
It's after I'm done with the fine tuning, when I go back to check for
anything that has slipped, that I find the middle of the piano and the
low tenor has crept sharp by a beat or even two.  

	 

	Immediately after the PR, do you check the middle section for
pitch?  

	 

	Yes, and it's almost always right on 440, so I proceed with the
fine tuning.  It's after the fine tuning that I find it has crept sharp
in the middle.  The low tenor is also quite sharp, so now I leave that
area a bit flat during the pitch raise.  And during the tuning (fine
tuning), the SAT always seems to "tune" the bass too flat, even if the
bass didn't need a pitch raise.  

	 

	 If it is at or near target, there is no reason for it to creek
up.  

	 

	One wouldn't think so.  

	 

	 How large a pitch gain are you talking about?  

	 

	Anywhere from just a few beats flat to a half-step flat.

	 

	 I've never noticed such a phenomena.

	 

	That's "phenomenon."  Phenomena is plural.  (Just for your own
info.)

	--David Nereson, RPT

	 

	Terry Farrell

		    

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