Cracking the unisons

[Ric Brekne]

I reprint Bernhards origional statement on the matter.  I personally 
dont see how it could be interpreted any other way then what he restates 
immediately below.  Bernhard is amoung other things, a person who 
actually has published software programs dealing with similiar issues.

This said... I think its time for Robert Scott to get on this thread and 
clear up this FFT bit.  A good generalized description of the basic 
pitch determination routines for the SAT, Cybertuner, Verituner, and 
Tunelab.  And if FFT is an intergral part... then it is period... even 
if one uses other approaches to finding the period of a given fundemental.


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 >> but if there is a way to measure a piano tone partial
 >> accurately in real time (or at all, for that matter) with FFT, I'd
 >> sure like to know the method.
 >
 >
 > there is actually no, that´s what i said.

It is? I must be reading a different language that you're writing
then. Sorry, I seem to have missed it altogether. Surely my fault,
as I'm sure you'd agree.

Awaiting enlightenment,
Ron N
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Bernard Stopper writes:

No they dont and there are good physical reasons why they dont.
(You will find not one tuner at Steinway (at least in Hamburg) who is
allowed to service concerts with an ETD for example). This has nothing
to do with traditionalism or ignorance to modern technology.
Most modern ETDs are doing fast fourier transformation (FFT) for
pitch calculation.
Be sure, the he ear has no FFT transformator... There is a big
difference in what you get measured and what you hear.
In some ETD manuals you find sometimes statements of "0.1 Hz accuracy"
This is true for a signal that would not float in pitch over more than 2
or 3 seconds to catch enough samples at the current possible
samplerates. Piano sounds are a really nonlinear matter that can float
in pitch up to some Hz over a second, when strucked firm. By
transforming a signal from the time domain into the frequency domain
with the desired accuracy (what most ETDs do), you loose the
information when a singal passes exactly what frequency at what time.
Tuning with an ETD makes it necessary to tune at low volume levels
(Pitch float is less at low volume levels). A good aural tuner tune with
a firm struck, to catch also the transient phase of the sound at higher
volumes. Low volume tuning is like not voicing the left pedal, it leaves
the transient phase untuned. But sometimes it may happen, that the
pianist also use volumes above mp...

Bernhard Stopper