Mike Knudsen writes regarding his 20-note Deleika organ:

> Question 1:  Are my bellows leaking,....
> Question 2:  ...The [single bourdon] are voiced too loud for the solo
> pipes, and a bit too "tubby" also..... So I'd like to throttle them
> back somehow. ... my ideal solution would be to replace them with
> narrower-scaled Rohrflotes, but that's a tad extreme.  :-)

Dear friends, "Extreme" is an understatement -- "uninformed" comes to
mind.  A finely voiced pipe organ is not a do-it-yourself job for an
amateur.  _However_, this situation (only 20 pipes) is very do-able.  :-)

Each pipe can be individually adjusted for volume, tone, speech, and
pitch.  The down-side is that changes to any one of these also affects
the others.  With care, you can do it.  But only one variable at a time!

1.  Find the defect.¶
2.  Remedy the defect.¶
(This is not a secret, but it's often ignored.)

First,  check your reservoir for leakage.  Do Not change the voicing on
any pipes until you have an airtight reservoir.  With the reservoir
isolated from the rest of the system, inflate the reservoir until the
spill valve opens.

Stop.  Time how long it retains some inflation.  If it's a minute or
more, consider them airtight.  If less than a minute, you may have a
leak; the larger the leak, the shorter the time.  Likewise, test the rest
of the system.  (You didn't say how the reservoir performed when new).

A quick-fix of rubber cement will only remedy porosity.  It should not be
used for re-gluing a joint; hot hide glue is the correct adhesive.  If
you use rubber cement, dust the cured cement _generously_ with baby
powder so you don't glue your gussets together.  (Quick-fixes are
generally frowned upon).  ;-)

Voicing is where artistry comes in, so humility is vital.  Years of study
and experience are needed.  You don't have them.  So,... proceed
carefully.  Do it in this order:

1.  Inspect the pipes, pipe valves, tubes, spill valve, etc. for damage,
kinks, slipped regulators, etc.  Correct any defects before proceeding.

2.  If your pipe valves are all opening properly and uniformly, look at
the pipes.  The "foot" of the pipe will have some means for regulating
the wind supply:  either a butterfly valve, a screw, a slide on the
toeboard, or just a lead toe.  Regulate the air supply to each pipe so
that they speak fully and promptly.  When done, go back through (at least
once) the entire set of pipes so that the loudness is appropriate for
each section, and uniform throughout the section.

3.  Tuning.  Do not change the windway, frein, bridge, upper lip, ears,
etc.  except in the most unusual of cases.  (i.e., you know what you are
doing, and know your craft as well as Deleika).

Just remember these important steps:

    1.  Find the actual problem.
    2.  Fix the problem.  First.

Only Then Correct voicing faults:

    1.  Regulate pressure at the reservoir.
    2.  Regulate pressure at the pipe.
    3.  Correct the tuning.

Robbie adds,
>[ I tried throttling the short air-calliope pipes to tame the shrieking,
>[ but it didn't work well.  Even after changing the "cut-up" (the big
>[ gap between the base and the resonator), it still didn't sound very
>[ good.  I didn't try making a narrower wind gap, which maybe would
>[ help....  -- Robbie

All else being equal, reducing wind pressure to a labial pipe calls for
lowering the cut-up.  Slightly, if at all.  High cut-ups permit pipes to
be blown harder without over-blowing.  That's why calliopes have such
high ones.

One variable at a time.  Go by small steps, as small changes have
enormous effects.  Caution: do not do anything irreversible unless you
have knowledge and experience (and can easily replace ruined pipes).

Best wishes,¶
Robert Linnstaedt¶
The Organ Shoppe, Benbrook TX