Matthew Caulfield asked:

> Are these designed solely for use in tuning stringed instruments or
> could they equally well tune wind-blown instruments (band organs)?
> Or is the nature of the band organ forgiving enough that investment
> in such high-tech and capable tuning instruments is a waste of time?

Generally speaking, electronic tuners for pianos are useful when tuning
organs, as Rob Goodale explained; anyway, there are some aspects for
which they must be used with care.

In pipe organ tuning, notes cannot be stretched when you move toward
extreme trebles and extreme basses; the stretching function of the
tuner should then be disabled.

Pianos have three (or two or one) unison strings for each key, so it
is enough to tune the strings of each triad at the same frequency.
In the pipe organ each key has a number of pipes generating different
frequencies corresponding to the various stops.

Some of the stops are not tuned in octave, but are tuned in fifths
or in thirds, etc.  If you try to tune those ranks using the transposed
notes of the tuner you'll tune the pipes according to the tempered
pitches; these are generally different from the pure pitches that you
should use instead.

An example.  For a stop in fifths [e.g., the 2-2/3 stop], the pipe
of the C key should sound a pure fifth; such frequency is very near
to a G, but is, usually, a bit sharper [than with a tempered interval].
If you try to tune it using the G of the tuner, you'll end up with a
flat-tuned pipe.  I don't know if common tuners have the capability to
manage correctly such situations.

There is also another aspect with pipe organs.  If the organ has a
number of stops, pipes tend to interfere one another in two main ways:

1.  The pressure and amount of air feeding each pipe varies slightly
according with the number of stops (and, hence, the number of pipes)
that are active.  This causes a slight detune of the pipes.  This
happens especially in channel-per-key wind chests.

2.  If the frequencies of two (or more) pipes is very near, they tend
to couple when played together, but they generate their own frequency
if played separately.  This phenomenon partially compensates the
previous.

Given these facts, it derives that pipes belonging to different stops
cannot be tuned individually; when played together with other pipes
they are easily thrown out of tune.

When I wrote my first tuning program (in 1985 with the glorious
Commodore 64), I was sure that it would suffice to tune the pipes one
by one according to the pitches generated by the computer, and I would
have the organ perfectly in tune.

First tests were very delusive, and, after hours and hours of "What the
hell?" and "*#@#%!&" and head scraping, I realized that when I tuned
the organs in the traditional manner without the tuner, being the
reference pipes in use, I automatically compensated variabilities.

In my opinion, tuners are useful for organs with one or few stops,
preferably unisons.  When tuning organs having a number of ranks,
with mixtures or ripienos, I use the program just for establishing the
temperament on the reference stop, usually a 4' stop (Ottava), and then
I go on the old way.  The program is far more useful when searching for
the original temperaments, but this is another story.

Hope my English grammar is not so bad this night; I have had a tiring
day today   :-)

Best regards to all

Leonardo Perretti
Italy

 [ That's a nice and clear discussion of a complex topic, Leonardo, and
 [ your grammar and spelling are just fine, and so is the 'cussing' !
 [  ;)  -- Robbie