Basic SAT III (& VTD) Questions

Joe & Penny Goss imatunr@primenet.com
Sun, 28 Jan 2001 09:21:25 -0700


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Hi Joe,
Terry"s advice is right on!
If you only tune by machine now, force yourself to trust yourself and =
your ear.
On every piano you tune tune a little by ear, make some checks by ear, =
and develope your listening skills.
Thus said you are probibly an aural tuner playing devils advocate, =
right? <G>
Even with good numbers you will find sections of some pianos that do not =
follow the nice even progression that the ETD's lay out.
If the stringer runs out of the correct size, they likely will not stop =
stringing while the gofer is getting the new canister of wire.
And in the bass replaced strings or a poor scale match will through off =
any well generated set of numbers.

Joe Goss
imatunr@primenet.com
http://www.primenet.com/~imatunr/

  ----- Original Message -----=20
  From: Farrell=20
  To: pianotech@ptg.org=20
  Sent: Sunday, January 28, 2001 8:01 AM
  Subject: Re: Basic SAT III (& VTD) Questions


  Comments interspersed below in original post:

  Terry Farrell
  Piano Tuning & Service
  Tampa, Florida
  mfarrel2@tampabay.rr.com

  ----- Original Message -----=20
  From: "joegum" <joegum@webtv.net>
  To: <pianotech@ptg.org>
  Sent: Saturday, January 27, 2001 10:07 PM
  Subject: Basic SAT III (& VTD) Questions


  > Hi.  I had the opportunity this afternoon to experiment with an SAT =
III
  > at a friend's home.  (My first experience with a VTD... II was =
trained
  > years ago as an aural tuner.) I was led through the F-A-C procedure, =
set
  > the temperament                              by device and tuned the
  > strip-muted middle register.  (The piano wasn't significantly out of
  > tune and very close to pitch.)  However, when I checked the octaves,
  > they were beating quite noticeably (one to two BPS).  Is this =
normal?

  On a well scaled piano with good FAC numbers (especially the "A" =
value), the SAT calculates 1/4 to 1/2 bps for all double octaves =
(without adjustment to the Double Octave Beat (DOB) feature). Dr. =
Sanderson designed the SAT this way as he felt this was a "typical" or =
average preference for tuners. So, on a nice Yamaha C7, NO this is not =
normal - on a rusty/crusty 1943 Betsy Ross spinet, it may not be too far =
from that expected.......but you can change it to suit your preferences!

  Understand that the FAC values (and let's just talk about the A for =
now) represent an inharmonicity value for that region of the stringing =
scale. If you have unrepresentative values (i.e., "bad" numbers), the =
calculated tuning may not fit the piano well. The "A" value is the most =
critical of the three by far. Dr. Sanderson and his son Paul do a class =
at the conventions where they go into much detail demonstrating this. I =
always measure all three strings of A4 when getting my "A" value (unless =
its a crudiano and I get a number that looks OK). If they do not seem =
"good" (either way off from that expected or light pattern was jumping =
all about) I will also measure the "A" value on several other nearby =
strings (within a couple of notes away - next door first). Again, A4 may =
not be a good representative note. It may be that the piano is poorly =
scaled and A4 is the last string of a particular size wire that ideally =
would have otherwise been a different size - that can certainly throw =
off an "A" value.=20

  Anyway, get the most representative FAC numbers you can (time and =
experience will tell you what is reasonable). My experience is that with =
"good" FAC numbers on a good piano, the calculated tuning is right-on. =
BUT, if for whatever reason you don't like what you hear (you have =
different tuning preferences, you have bad FAC #s, a bad piano, or its =
just a bad day - poor planetary alignment, etc.) just adjust the stretch =
with the DOB and you have equal temperament with YOUR ideal stretch =
amount (scrunch it or expand it). That is what the DOB is for. And you =
can change it in any region of the scale to your preferences. You may =
find that you ALWAYS like more stretch than the standard SAT calculation =
provides - you may want to start adding 0.5 (or whatever) to your "A" =
and "C" values when initially entering FAC numbers because you have =
found that this will calculate a tuning more close to YOUR preferences =
(you will learn to customize your initial tuning to your liking - I like =
the standard approach and do not generally change the FAC numbers).

  This is presicely why "machine-only" tooners can - and often do - do =
poor work. Your ears MUST dictate what you are doing. The advantage of =
the SAT is that once you verify that your calculated tuning is to your =
liking (by doing a few octaves and other intervals - whatever makes you =
comfy and happy) you can then follow the machine and produce a very fine =
tuning without ear strain (unisons excluded, of course - although on =
rough pianos, the top several notes on my tunings often have unisons set =
by machine!).

  > Is it now in some circles considered acceptable for octaves to be
  > stretched this much?

  You tell the machine exactly how much to stretch the octaves. Don't =
let the machine tell you what is or is not acceptable. It's name is SAT, =
not Hal.

  > When you use a VTD in noisy conditions, how can
  > you have faith in what it's telling you without the benefit of aural
  > verification?

  Boy, this is one I have red hot advice on........Yesterday I was =
tuning at a festival concert.......(see my other posts on 1st concert =
tuning)

  First of all, you ALWAYS WANT aural verification. I was able to do =
that yesterday at the beginning of my work. I did my FAC (even on this =
Yamaha, the three "A" values were (I think) 7.3, 7.8, and 8.4. I =
certainly like (and expected) them to be closer together (like within =
one or two tenths), but time was critical so I used 7.8. Muted off all =
the "A"s, tuned them to the machine. Listened to octaves and double =
octaves. Everything sounded right-on. This combined with having tuned =
many similar Yamahas with excellent results, made me feel totally comfy =
knowing that as long as I can "stop the lights", keep the pitch there, =
and tune good unisons, we would have an excellent tuning - even if I =
never was able to do any tests after-the-fact (which I did not have the =
opportunity to do). If you are unsure that you have good numbers, or you =
don't have a good piano and you don't get to listen to your tuning tests =
- the SAT may well calculate a "bad" tuning. It only does what you tell =
it to do.

  BUT, I will go one step further. If I were tuning a Yamaha C7 in real =
nice shape, got three "A" values that were real close to one another, =
all FAC values were within the range of what you would expect, I would =
feel comfortable tuning that piano with the machine and not ever being =
able to test the tuning (keep in mind, if there is THAT much noise - no =
one else will be able to tell if it is out of tune!). But the thing is =
of course, if you can tune the unisons by ear, you should be able to at =
least listen to a few octaves to get a basic feel of whether the =
calculated tuning will work. I will also say that I have never tuned a =
piano in the manner just described - but if I had to, I think I could.

  >  If the stretch is adjustable, can the stretch be reliably
  > individualized for each instrument without aural verification?=20

  NO!  You must listen to the calculated tuning, and adjust the stretch =
so that your ears and tuning preferences are satisfied. The ONLY way to =
use the DOB (properly) is to listen and adjust. The only reason to use =
the DOB is because your ears have told you that the calculated tuning is =
not what you like. The machine MUST be manipulated so that it reflects =
what YOU like. NEVER assume the machine knows something you don't. It =
can take three numbers and calculate a tuning with amazing results. BUT. =
The SAT is like an automobile. YOU MUST drive it. If you let go of the =
wheel you are dead. BUT the automobile sure does make getting there =
easier, doesn't it?

  > Thanks
  > for letting me pop back onto the list and ask these questions.  -Joe
  > Gumbosky                      =20
  >=20
  You are welcome. Hollar back with any questions! Good luck!

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