A Busker Organ with 2 Registers and 29 Pipes

by Melvyn Wright

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Busker Organ with 2 Registers
Yes you read it right, you can make a John Smith Busker organ with multiple ranks of pipes!

The General Idea
Because the pipes in the Busker organ are blown directly through the holes in the paper roll, there is only sufficient wind to blow one pipe per note.  But there is nothing to stop you from having 2 or even 3 sets of pipes with a different tone, as long as only one set of pipes is connected at a time.  Using this idea, you can switch between each rank of pipes and have a 2 or 3-register organ.  For instance, you could have a set of stopped flutes and a set of open flutes, and a stop knob on the side of the organ to switch between the two different ranks to vary the tone.  I mentioned my simple idea to John Smith in 2009 and, surprisingly, he said that he didn't know of anybody who had thought of doing this.

For a 2-rank organ, it is only necessary to provide 9 additional Melody pipes, and as these are the smallest pipes in the organ, the organ does not need to be much bigger than the original.  The Accompaniment and Bass pipes are not duplicated.  As the two ranks of Melody pipes will be in front of each other, the organ needs to be about 3" deeper from front to back, and possibly slightly taller but that depends on how the pipes are arranged and mounted.  The extra height is due to the slider mechanism underneath the pipes, and not to the length of the pipes themselves.  In theory, the 9 additional Melody pipes (D to D) should be twice the length of the original stopped pipes, but they turned out to be much shorter than this, and still shorter than the existing accompaniment pipes.

A simple slider mechanism is used to switch between the two ranks of pipes.  The slider has two rows of holes in it, which are staggered so that only one row of holes lines up with the pipes above.  Pushing the slider one way will line the holes up with the front rank of pipes, and pushing the slider the other way will line the holes up with the back rank.

Here is how I built a 2-rank Busker organ pipe unit.  Please note that I am a music arranger and not an organ builder, and this first attempt was an experimental prototype, so it is a bit rough and ready, but it works!  By all means implement your own improvements.

CONSTRUCTION


The new set of 9 open flute pipes

The extra pipes are made using exactly the same techniques as the pipes in the plans.  Balsa wood, and hardwood parts for the mouths. Nothing fancy!  (The wonky chamfers won't be seen, as they are behind the normal pipes.  Must remember to take more care next time!)

For reference, here are the lengths of my 9 extra pipes (yours may be different):

D = 139 mm
C = 159 mm
A# = 173 mm
A = 179 mm
G = 200 mm
F = 230 mm
E = 241 mm
D# = 250 mm
D = 255 mm

The Extra Pipes
The first thing I did was to make a set of nine open flutes and connect them up in place of the nine original Melody pipes to check that my idea would work, as there was no point in continuing if they wouldn't play properly!  This was meant to be a quick lash-up but it was anything but quick. It took me hours to change the tubes over, extending them where necessary; and then tune and voice the new pipes on the organ pressure.  Pipes were hanging out all over the place, but it played perfectly, and with a brighter tone.


Testing the feasibility of my idea.  The alternative pipes 'plumbed in' in place of the original Melody pipes!

 Because the new pipes needed to consume the same amount of wind as the original pipes, and were to be mounted behind them, they must be exactly the same width as the original pipes. Open pipes sound an octave higher then stopped pipes, so I made the lengths twice as long as the original pipes (although they turned out to be quite a bit shorter than that).  To provide a bit more variation in tone I increased the depth of the pipes to be about 1.5 times the depth of the original pipes (with hindsight, I think it would have been better to keep the same dimensions, as a smaller pipe promotes a brighter tone).  I also gave the top lips a razor sharp edge instead of the slightly rounded edge of the stopped pipes.

The original pipes were fixed to a flat panel on the front of the organ, but this method will not now be possible, as the pipes have to stand on their feet in 2 rows.  This means that the air tubes have to enter the base of the pipes, and not the back.  Therefore, if you are using your original Melody pipes for one rank, you will need to remove the air tubes from the backs of the pipes, glue a piece of cardboard over the holes, then make new holes for the tubes to go in the foot of the pipes.

The Slider Unit
Having made the extra pipes, I then made the slider unit to stand them on.  I made this out of MDF (my Busker organ is made almost entirely out of MDF and I have had no problems with it).  It might look complicated, but there are no special construction techniques involved.  It is just strips of MDF or plywood glued together with holes drilled through.  Where you want an extra thickness, just glue two strips together.  No measurements are given because the unit must be made to fit your pipe layout.  First, decide how you want to lay your pipes out, then measure the overall width of the pipes, and make the slider unit to suit.

First of all, the top board was made and drilled to take all of the 26 pipes mounted on the front of the organ (the original 17 pipes plus the 9 extra ones).  As you can see from the photos, there are now 2 rows of 9 Melody pipes in the centre.  The 8 Accompaniment pipes are mounted in a square formation, 4 at each end.  The air tubes are taken directly to the 8 Accompaniment pipes, just as in the original design, and I drilled channels in the MDF and mounted brass tubes at the back for connection purposes.  But the plastic tubes could just as easily be taken straight to the bottom of the pipes, for simplicity.  Note the larger tubes for the 2 biggest pipes. 


The top fixed board on which all the pipes are mounted

The air to the Melody pipes goes through a slider mechanism, as already described.  This is mounted underneath the top board and distributes the wind to either the front row or the back row of Melody pipes.  The bottom board of the slider mechanism is shown below.


The bottom fixed board of the slider unit.  Note the channel for the slider

The holes in the bottom board all line up with the holes in the top board, and should be drilled at the same time. Horizontal channels are then drilled underneath these holes, and are taken to the brass tubes at the back.  As can be seen, I turned these tubes through 90 degrees to enable an easier connection to the tracker bar, but that is optional.  All internal channels should be made as large as practical, to provide minimum restriction to the airflow.

Now, if this unit is fixed directly underneath the top board, blowing into each of the brass tubes would sound 2 pipes.  This is not what we want, so a sliding board is sandwiched in between the top and bottom boards, to 'switch on' either the front rank or the back rank.


The bottom board with slider in position (the ends of the slider have yet to be cut off).

The above photo shows the bottom board with the slider mounted on top.  The slider is made from 3mm MDF and slides in between two narrow strips of the same thickness MDF glued to the bottom board.  As can be seen, the two rows of holes in the slider are staggered, so that one row of holes is opened and the other row is closed.  Moving the slider across to the right will reverse the position and switch on the front row of pipes.

Two strips of paper are now glued to the bottom board, as shown in the photo above, and these are then glued to the underside of the top board, making sure that all the holes are in alignment.  Clamp the whole thing together, inserting drill bits through at least 2 of the holes to make sure that all the holes are lined up.  Before the glue has dried, remove the bits and make sure the slider slides freely.  The strips of paper provide a small clearance for the slider to move freely, but not enough so that air will leak from the holes.  When the glue has dried, the slider can be removed and smoothed down.  You can of course use screws to fix the units together if you prefer; but the paper strips do provide a weak joint for the units to be separated in the future, if necessary.


Top view of the complete slider unit


Bottom view of the complete slider unit.
 Note the square cut-out on the left-hand side which limits the movement of the slider in each direction.

A stop is provided to limit the movement of the slider in each direction, by means of a screw fixed underneath the top board, working in a square cut-out in the slider.  This can be seen in the above photo.  Removing this screw also allows the slider to be removed.  Make sure that the holes in the slider line up exactly when it is at the limit of its travel in each direction.  A block of wood is glued to the other end of the slider to provide an anchoring point for the operating rod, which will stick out of the side of the organ.  Pushing and pulling the rod will switch between the 2 sets of pipes.

Unfortunately, now I've built the unit, it won't fit in the original organ, so I need to build another organ!

                                                           
The complete unit ready for mounting in the organ
You can see the 9 new pipes standing behind the original Melody pipes in the centre

 

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