Roger Waring wrote in MMDigest 981105:

> It seems to me that any artificial device, whether an electronic box,
> or a computer microphone feeding into software, has considerable
> limitations.  I have tried one program, and from experience find that
> it can only tune one string at a time.  This therefore has obvious
> limitations, not least on setting perfect unisons and on establishing
> correct intervals.
>
> No, I'll stick to my flaps -- when some device comes along that tells
> me that C-E is beating at 10.38 [Hz], _then_ I will be impressed.

Hi Roger,  Okay, I'll impress you!  As a professional Registered
Piano Technician (RPT) perhaps I can clear up a little confusion on
Electronic Tuning Aids.  ETAs are really not intended to completely
replace aural tuning.  In fact any tuner/technician still requires
a fundamental understanding of aural tuning in order to use one
correctly.  Equally important are the proper techniques of using the
tuning hammer.

There are several "electronic tuners" on the market, most of which are
useless in tuning pianos.  I specifically refer to those sold over the
counter at music stores.  In order to tune a piano properly the device
must be able to set the temperament on the instrument with extremely
close accuracy.  To do this it needs a built-in computer to perform the
required complex calculations.

There have been a number of pre-computer revolution devices in earlier
years that have been labeled as "electronic piano tuners", but really
didn't have the ability to calculate tuning scales.  Today there are
a few "real" electronic piano tuning devices that are extraordinarily
accurate.  The most popular of these today seem to be the Sanderson
Accu-Tuner, more commonly referred to as the SAT:

    http://www.concentric.net/~fast440/

and the Reyburn Cyber Tuner, or RCT:

    http://www.reyburn.com/

The SAT has been around for a number of years now, the latest version
of which is called the SAT III.  The SAT II still remains the popular
favorite but the III has just come out this year.  The SAT is a
self-contained unit that not only can calculate the temperament with
amazing accuracy, but can also store dozens tunings in memory to which
you can go back for future use.

It can also perform other tasks such as pitch-raise calculations,
off-set pitch standards (such as tuning to A435), and has MIDI ports
that allow the user to down- or up-load tuning data from a PC.  It
has a built-in rechargeable battery, and is reasonably compact.

The Reyburn Cyber Tuner works in a similar fashion but has a few
additional bells and whistles such as custom and historic tempera-
ment calculations.  A limitation of the RCT is that it is actually
a program, not a real tuning device.  It is intended to be installed
on a notebook computer.  Both the SAT and RCT are professional items
and carry a hefty price tag.  I think I paid around $1,500 for my SAT
about five years ago.

In both cases the SAT and RCT require that the user first take aural
measurements from the piano.  This is done by tuning certain notes as
instructed by the machine, (F2, A4, and C6 in the case of the SAT for
example), and then allowing the computer to listen to these tuned notes
again in a different mode.  By listening to the complete partial series
of each note the device is able to calculate the temperament scale.
The whole process takes about 3 minutes.

I'll quickly mention one more; the Yamaha PT-100 Tuning Scope.
This unit is easy to use and looks really cool but does not have a
calculation computer.  Instead it has several built-in generic tuning
scales.  As you might guess they are tailored toward the Yamaha piano
line, but can often work passably on other pianos.  They run around
$700 or so.  I have one but haven't used it since I purchased my SAT.

As for the actual tuning process, understand that you only tune the
center string as you would with any ordinary piano tuning.  You need
to install a temperament strip, get your mutes out, and go through the
whole typical process.  Although you technically can, with any elec-
tronic tuning aid you must tune the unisons to the center string in the
normal manor if you expect them to be clean and reliable.

I have passed the Piano Technicians Guild aural tuning exams with
flying colors but still use an Accu-tuner regularly.  Some aural
touch-up may still be required but, generally speaking, I find that
it can tune just as well as I can only a lot faster and with fewer
headaches at the end of the day, (and your listening to a guy who's
tuned thousands of pianos).

Here is a program called Tunelab that is down-loadable for free.
I have never tried it so I cannot comment on it's performance.
You will find it here:

    http://www.wwnet.net/~rscott/

Best Wishes,

Rob Goodale, RPT