Tuning the Reeds
The speed at which the brass reed tongue vibrates determents
the pitch the note produced.
A reed should be removed for tuning. True, you
can tune it when it's inside the organ, but it's a lot
easier and safer doing it outside.
The reed can be tuned to its octave, i.e., in other words,
if you're tuning Middle C, you can tune it to either Tenor C or
Treble C.
You can also tune it to another reed in a different rank.
It's also a good idea to tune the reed to another reed in a
different octave. In other words, a 4ft C should not be tuned
to another 4ft C.
It's important to give special care to the reeds, as the
metal is often quite brittle and the tongues can easily
snap.

A is the vibrating end, or front, and
B is the riveted, or back end of the
reed
A jeweler's file is usually the best way to scrape off a
small amount of brass from the reed tongue.
If a reed's tone is flat (a lower pitch) you'll need to
quicken the vibration speed. To do this, carefully scrape a
very small amount of metal from the reed tongue at point A.
On the other hand, if the reed is sharp (a higher pitch)
you'll need to slow the vibrating speed down. To do this, you
carefully scrape a very small amount of metal from the reed
tongue, as shown at point B.
Unfortunately, this process is a matter of trial and error.
Scrape a small amount of metal from the tongue, replace it and
test its tuning. You may need to scrape off a little more
metal, or if you have tuned the reed too sharp or too flat, you
will need to scrape the other end.
Tuning Software
For several years now I've been using some software called
TuneLab. It was actually designed for
piano tuning, but works just fine for pump organs. You can
simply load it to your laptop and you're in business. Robert
Scott is the software designer and knows his stuff. Of
course you'll need to pay Robert something before you can
download it.
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