https://www.sentex.ca/~mwandel/organ/organ.html
The story of my home made pipe organ
Playing on my organ
Playing with (not on) my organ
Not so early beginnings
It all began in the fall of 1992, in my final year of university. For
lack of a better arts elective to take, I decided to take Music 111.
I had absolutely no background in music at the time, and sometimes
even had trouble telling whether two consecutive notes were ascending
or descending. Nevertheless, I bravely decided to take the course.
As the course progressed, I discovered that some of this stuff was
actually logical, and also kind of fun. I found myself using the
piano room just to play around. I never cared much for attempting to
play sheet music, but the idea of hitting keys and getting a sound
that was sometimes harmonious was strangely appealing.
With my nonexistent music abilities, and my limited budget, I
couldn't justify buying myself a little Casio synthesizer or
something like that. The only way I could justify owning a musical
instrument was if I actually built it.
I am very fortunate that my dad has a very large and wonderful
woodworking shop. When I went home for Christmas that year, I started
experimenting with organ pipes. That Christmas was particularly busy
for me, as I also built two tables, because the house I was renting
with friends was a little bit under-furnished.
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Experiments and design
My first organ experiments were high in volume, if not in harmony. I
proceeded to build two wooden pipes, and mounted these on top of a
box with a vacuum cleaner motor inside
First pipe experiment My first organ pipe experiment
From these experiments, a few things became apparent:
A vacuum cleaner motor is WAY too noisy
A vacuum cleaner motor produces more than enough pressure
High air pressures can cause pipes to play anything but their
fundamental
My basic pipe design was quite capable of making noise
Everybody in my family teased me about even considering building an
organ, and to tell the truth, I wasn't so sure at that point either.
I did experiment with slowing down the vacuum cleaner motor (the
black cylindrical thing to the left of the box is a 1 kilowatt
Variac), which helped, but I left it for the time being.
I proceeded to build the two tables I had intended to build over the
holidays, and then to experiment further. I knew I could build pipes
to play just about any reasonable pitch I wanted to, as long as I did
not apply too much air pressure.
My next set of experiments revolved around coming up with a simple
'valve box' design that I could build. At the time, I didn't know
such a thing in organ terminology is called a 'wind chest'. Another
catch was that I did not have a good supply of leather for the
'gaskets' in the valves, so the design I came up with did not use any
gaskets.
Overall windchest design and dimensions
This drawing shows the cross section of the wind chest design I ended
up using.
The drawings came much later though. All dimensions are in
millimeters.
Wind chest design & dimensions The letter labeled components are as
follows:
A White key
B Black key
C Felt for white key bottom stop
D Felt for black key bottom stop
E Metal bracket to support shaft every 12 keys
F 1/4" steel shaft for key 'hinge'
G Top stop for keys (only gets hit if are let 'snap' up'
H Nail in back of keys, with steel wire twisted on
J Steel wire
K Small opening with felt padding to pass wire into pressurized wind
chest
L Removable portion of wind chest lid
M Steel spring to hold down valve block
N Valve block. Valve block seals against wind chest bottom
O Wind chest bottom
P Plastic hoses leading to pipes
The valve blocks are all sanded smooth, and so is the bottom of the
wind chest. The leaf springs apply pressure exactly over the center
of the hole below, thus causing for a tight seal of the two flat
surfaces. The valve blocks are rounded slightly towards the back.
This gives for a more gradual opening, and quieter operation (at
least that's my theory).
Wind chest cross section with key pressed
Key action As I chose not to have a complicated linkage between the
keys and their corresponding valves, it was necessary to have the
valves at the same overall spacing as the keys. I accomplished this
by breaking the valves into two rows of whole-tone scales.
The pipes themselves are of course much wider, so I used plastic
tubing to connect the valves to their corresponding pipes.
Valve block details
Valve blocks
A Hole for back alignment pin (nail)
B Block for end of leaf spring to push down
C Pin for attaching steel wire to actuate valve
D Slight bevel at front to ensure good contact on main area
E Slight bevel on back for valve to 'roll' back on. Causes more
gradual opening
F Flat main area to seal against wind chest bottom
G Block to clamp two metal springs
H Valve block in place over opening
J Valve block back alignment pin
K Valve block front alignment pin
L Hole in bottom of windchest with plastic tubing
The original experimental pipes I built were of a difficult design to
execute, as the front of the pipe was actually sandwiched between the
two sides. This was good for initial experiments, especially when
testing the pipes for different configurations before I glued them,
but not for making large numbers of them.
The next pipe design I came up with is much easier to build:
Pipe Design
Design of the pipes
A Top of pipe. One piece
B Block to form air gap for air to come put
C Small wooden insert to adjust opening of the mouth (voicing)
D Block at top of organ, cut out for air passage from hose to slot.
E Small wooden block for tuning pitch down if I cut the pipe too
short
This design does have a major weakness in that the block 'B' must be
precisely fit into the slot. If it is too narrow, air escapes from
the side.
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Construction
Using this design, I built about 3 octaves worth of pipes. I varied
the geometry as I scaled the pipes, so that long pipes were more
slender with respect to their length than the short ones. This
produced a louder sound in the higher octaves. I also found out that
pipes that are long and slender are much easier to tune, and keep
their pitch much better across a wider range of operating pressures
and surrounding geometries.
I did run out of time that Christmas holiday, but the result was
already playable. I didn't obtain a better air pump than the vacuum
cleaner motor. So what I did is put the vacuum cleaner motor into a
box, which was surrounded by foam, which was contained in a box of 2"
hardwood, which I surrounded by foam, which I put into a cardboard
box. With the vacuum cleaner running at about 40 volts to get the
right pressure, the noise was tolerable.
I took what I had with me back to University, and set it up in the
living room of the house where I lived. Even though we had a modular
MOOG and a Jupiter 6 synthesizer set up in our 'studio', my house
mate Keith and I ended up playing with that organ an awful lot. 4
months later I had to re-varnish the keyboard. We had worn four
layers of varnish straight off the keys!
Wind chest inside
View into the windchest, with one valve block removed
The valve blocks are pulled by the steel wires, which are simply
twisted onto a nail sticking out of the back of each key. This is
primitive, but works quite well. Being able to adjust the length of
the wire by twisting it slightly is important, as it determines how
far down the keys are when not pushed. If the keys are not level it
looks really dumb.
Also, note the yellow spacers between the keys. These are to keep the
keys from rubbing against each other directly, and also reduce
friction. In the winter, I always need to add some spacers to get the
keyboard to feel 'tight', while in the summer, I have to remove them.
This is all caused by wood shrinkage and expansion from changes in
humidity.
Organ in early 1993
The pipe organ, as set up in early 1993
I hadn't had time to build a stand, so all the pipes were just
stacked under the keyboard unit in that first setup. Some were
dangling from their plastic hoses, some stacked with wooden blocks
between them. This was a terribly precarious arrangement. Every time
the stack of pipes was bumped, they shifted slightly, and would alter
their tuning. The sound of these pipes is very sensitive to their
immediate surroundings, I discovered.
Ends of the pipes
End view of the loosely stacked pipes.
I spent a lot of the next 4 months fine tuning some of the pipes, as
well as adding felt under the keys to dampen the noise they made when
they hit bottom.
Tuning the pipes without having convenient access to a woodworking
shop was also more difficult. They way I had originally tuned them
was to tune my Commodore 64 to the pitch the pipe was playing, then
work out the frequency I had tuned the computer to, calculate the
corresponding reduction in length of the pipe, marked it on the pipe,
and then took it to the shop to cut the pipe off on a band saw. This
worked for tuning up. For tuning down, I could place a small block of
wood in the end of the pipe to reduce the pitch. For minor increases
in pitch, I also ended up flaring the end of the pipe with a knife.
I also ended up finally replacing the vacuum cleaner motor with
something more elegant. It turns out that running at about 40 volts
for extended periods was not good for the vacuum cleaner motor.
Carbon deposited between the copper contacts on the commutator, and
then conducted electricity and started to smolder. My theory was that
the motor's design intended for centrifugal force to clear the carbon
dust from the commutator, but at the low speeds at which I was
running it, this didn't happen.
Organ pump & motor
The organ pump and motor
After the vacuum cleaner motor died, I was very lucky to find a 1/
12'th Hp motor and precision blower at Princes Auto (A surplus
store), for a grand total of $20. I used a scrounged O-ring as a
belt, and adapted the paper feed pulley from an old teletype by
sanding an indentation into it for the O-ring to run in. The pulley
on the blower also needed modifications, so I removed the shaft and
cut a groove for the O-ring into it on a metal lathe in the student
machine shop at the University.
This combination I placed in the box I had built of 2" planks. The
combination was so quiet that its noise became a total non-issue. At
about the same time the real vacuum cleaner we were using in the
house died, and I was able to reuse the bearings from that motor to
fix our actual vacuum cleaner.
The organ in the 'studio'
The organ in the 'studio' we had set up
We had quite the studio setup at the time. Bottom right is the pipe
organ, behind it the Jupiter 6. To the left is the modular MOOG
synthesizer (two VCO's 1 VCF, 2 envelope generators). In the back is
one of our reel to reel tape decks, the drum machine, and a DSP sound
processor box.
Also note the knife set on the cardboard box in front. I used the
knife set for tweaking the wooden pipes, and the cardboard box it is
resting on has the vacuum motor blower in it (for extra insulation)
If you are wondering, the box in the back IS a box for a lava lamp.
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Finishing up the organ
Pipes being glued Gluing the 4 ft C, D, and D# pipes
Later that year, after graduating from University, I spent another
week in my dad's shop and finished it up. I had previously not fully
'populated' all the possible notes of the keyboard. I rebuilt the
uppermost half octave to change the aspect ratio, and extended the
range by half an octave at the top, and three notes at the bottom.
Before this, the organ's bottom octave, and top half octave keys only
made an air escaping type of noise when they were pressed.
Pressure regulator Pressure regulator, with rocks to control pressure
and foot pedal
I also built a pressure regulator for the organ. This regulator
consists of a simple bellow, about 20cm x 20cm, but with only 3 cm of
travel. This bellow was not so much intended for a reservoir, but
more as a pressure sensor. When the bellow falls, the valve at the
bottom of the bellow opens further to let more air from the blower
in, thus maintaining the pressure. The pressure can be varied by
piling various amounts of rocks on top of the bellow, as well as by a
special foot pedal which can be used to apply extra pressure to the
bellow for 'expression'.
[regulator_] [bellows_in]
Bellows opened up I took some photos of the regulator disassembled.
The left shot is the valve at the bottom of the regulator. When the
wire at left is pulled up, the assembly pivots to the right on the
shaft, and closes off the air inlet on the bottom of the bellow. The
wire is attached to the bellow. When the bellow has enough pressure
in it, it lifts up the rocks piled on it, and also pulls up on the
whire, which closes the valve.
The keyboard and upper two octaves Keyboard and upper two octaves
This picture shows the organ with the top flipped up. This is not
optimal for playing however, as the organ, because I tuned it with
the lid down. Organ pipes are very sensitive to the shape of their
immediate surroundings.
The complete pipe organ This is how the organ is set up in my living
room today. I only play with it occasionally, and only when I am
certain that I'm alone. Every once in a while, I have a visitor who
is musically talented, so the organ does get some use. It's also a
great conversational piece!
More pictures of the organ and its construction
I contemplated building a better organ with multiple registers. I got
as far as making a few drawings on the computer, but then abandoned
it. Here's a few pictures of my preliminary plans for organ 2.
A short video opening up the organ
and showing how it works.
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Sound and video samples
Sound samples
A low C-cord sound sample (43 k)
A higher C-cord sound sample (38 k)
A simple sequence of notes even I can
Michael Dunn playing part play (63 k)
of Bach #2 prelude in C
A scale played in 4 octaves at once
(124 k)
A short sound sample of Allison
Wolanski playing an original piece
A catchy little MIDI tune I composed
years ago but can't play (1k Midi)
More on organs and musical instruments
The Art of Organ Building* - The definitive work on building
traditional organs. Published over 100 years ago.
Touring an Organ builder's workshop
Raphi Giangiulio's home made pipe organ - a much more elaborate
home made pipe organ than the one I built! He credits my organ
for having inspired his.
An Italian Virginal Got a nice e-mail from Mario Giardini, who
also built a musical instrument - a "virginal", which is a
harpsicord-like predecessor to the piano. Very nice page.
More pictures of the organ and its construction
Touring an organ building workshop
To my Building a ukulele
To my Woodworking website
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