Frequency accuracy?

[Elian Degen J.]

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Hello, Brian

As I have been working with electronic equipment also, I have a modular =
tectronix unit which has oscilloscope, frequency meter, frequency =
generator, and a regulated power supply. From time to time this =
precision instrument goes to calibration, and I check my piano ET with =
the frequency meter from time to time to check for accuracy. I have =
always used Yamaha, I am not promoting it, but that is where I have =
experience. I had several models, all of them well over US$ 200.00 At =
least on these equipments I never had any problem with calibration, they =
always measured precisely. If the equipment is well built it will be =
much more precise than a tuning fork, reason is that they use as a base =
for comparison a quartz crystal which is very precise. As for tunings, I =
agree with you. I finis my tunings auraly, and my customers also like =
that final touch. =20
Elian=20
  ----- Original Message -----=20
  From: Brian Trout=20
  To: pianotech@ptg.org=20
  Sent: Thursday, June 17, 1999 8:08 AM
  Subject: Frequency accuracy?


  Hi,
  =20
  I have been tuning aurally for most of the time I've tuned.  When I =
first started out, I got a chrome plated steel tuning fork.  It's not =
very loud, but it seems to be pretty stable.  I've heated it up to well =
over 100 degrees, and put it in the freezer to cool it down, and =
measured as best I could in both extremes.  It doesn't move much, =
perhaps 1 or 1 1/2 cycles from one end of the extreme to the other.  =
(It's hard to measure, because it starts changing back to room =
temperature before I can really get some good "listens".)
  =20
  At work amongst the tuners, we have 3 tuning forks, and 3 "machines", =
none of which are over about $200 machines.  My personal observations to =
date lead me to believe that the forks are all very close to each other. =
 However, the machines are quite different, one of which actually tunes =
a piano sharp enough to hear audible beating when played with another =
piano tuned with a fork.  (This is when you're trying to set the pitch =
at A-440.)
  =20
  My question is, how does one determine which A-440 is right?  Is there =
an easy way to do that without finding an electronic frequency counter?  =
I can't think of anyone who has one.  I'm just trying to figure out if =
real tuning fork accuracy is possible in a real world.  To what do we =
pay homage as the "ultimate" standard measuring device?  Who's =
"ultimate" standard measuring device is right if they don't agree???  If =
I find one person with an SAT and one with an RTC and the A-440's aren't =
the same, who's right?
  =20
  I'm not trying to be obnoxious here, but I've been reading about the =
"big test", and what's involved.  It all starts with the basic premise =
that we start at A-440.  It's been worrying me a bit.  Who's A-440?
  =20
  Any thoughts out there?
  =20
  Brian Trout
  Quarryville, Pa.
  btrout@desupernet.net
  =20

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