Operating procedure

To make wooden pipes you need a circular saw, followed up by a shredder machine, an electric drill, and perhaps a milling machine and a sander. Opposite it is the construction of metal pipes; it happens in a salutary calmness. The pipe maker sits at the table and cuts the metal to the right sizes. He gives the metal its right shape to roll it around a cylinder and closes the seam by soldering. A soldering seam doesn’t need time to dry or to harden, a big advantage compared to the glued seams of wooden pipes.

The tools are limited, just al soldering iron, a small plane to give the languid a 60 degrees angle, a small Stanley knife and a burnishing steel for molding the labium shape. After cleaning the pipes are ready to be voiced with a great refinement, impossible for wooden pipes. If desired, metal pipes can be voiced to more gentle and sensitive sounds. The loudness is just dependable of the air pressure like wooden pipes, but where the wooden pipe reaches his end, the metal pipe can bended more into the weak air flow and it will still sound. An air pressure of 25 mm is sufficient for my small table positive.

Don’t see the making of metal pipes as a jump in the uncertainty. The wood worker should learn a new technique and he will be amazed how quick he is a skilled worker. To learn it is written extensively in the book Building a Positive organ and there is an instruction film on DVD with English subtitles available see: bestellen van orgelboeken (ordering)
or sent an e-mail to: John Boersma. It is impossible to reach this sound with wooden pipes. Besides, metal pipes can be voiced very sensitively to delicate sounds. A try out is easy to do with a pipe of lead from the plumber as drawn at

          1. Drawings to make a pipe            2. Photographs to make a pipe
Sounds from lead and tin Sounds of an Organ
                                                                                                   
Organ pipes are made from organ metal, an alloy of lead and tin. A high percentage of lead gives the sound of the organ the necessary gravity. The Henric Bader organ in Zutphen has even pipes that are completely made of pure lead. With a high percentage of tin a pipe gets a shiny appearance, but the assumption that also the brightness has grown is wrong. Experiments that I undertook with the Swiss organ builder Christian Gfeller proved that the sound is not only dependent on the material, lead or tin but the thickness of the pipe wall has influence. With tin you can make thinner pipe walls. In addition to the gravity, the sounds of lead pipes have also a great clarity.

The timbre of a Principal is characteristic for the organ sound and although Principals differ on ech organ, the Principal sound of any organ remains recognizable. The musicality of the organ is characterized in the resonance of the typical overtones. This resonance is promoted by planing the pipe wand upwards thinner. In addition to this singing register, an organ has also register with flutes, a sound with few overtones. If there are dark round sounds, like the Stopped diapason or the Subbass, these pipes can be made of wood.

Amateur Organ builders

Amateur organ builders make all pipes of wood. Wood is the only material with which they have learned to work with making the case, the wind chests, the wind supply and the keyboards. A professional organ builder knows that a beautiful sound is only to achieve with pipes made of metal and he uses only wood for a the Stopped Diapason or a Subbass.

Lack of courage denotes an amateur; they never make a step along an unknown path. Despite the beautiful sounds of metal pipes, they just make all pipes made of wood. Learning a new technique is pushed aside as too difficult.

For once I could convince sometimes a single amateur that no beautiful organ sounds can be get with wooden pipes. And always, they came up with the unexpected discovery: making metal pipes is lighter than wooden pipes.

Moreover, and this is much more important, metal pipes can be  voiced quite nuanced to brilliant sounds. This is the aim of organ builder, to attract sounds which have something to say musically.

The most beautiful sound of an organ is that of the Principal stop. It is the basic sound of the organ and there sounds a clear formant. A formant is a group of harmonics that independent of the tonic will be heard at any pitch. A good sound can only be reached with metal pipes. Metal is the right material for the sound of the Principal as it is for the delicate sound of the Viola di Gamba.

Voicing Organ Pipes

Make sure that the languid looks perfectly with an even width. The edges must be clean and show no residual color or metal particles. Just then the exact location of the languid in relation to the under lip and the upper lip can be determined. The wind flow from the languid forms the air blade and it must reach the upper lip on the right way.

Begin with blowing the pipe softly and let increase the wind pressure slowly. Listen how the sound changes. The response of the pipe can be too fast or too slow. If the air blade is directed too much inward, the response will be too fast.  If the air blade is too much away, the response will be to slow.

Tools

The most important tool to form the metal is the lip raiser (voicing lance). It can be used to pull the upper lip forward or pushed it more inside. The second tool for the same purpose is the burnisher. The languid interstice gets his place and form with the voicing lance and the burnisher.

The width of the languid interstice is usually between 0.2 and 0.5 mm and it can be determined by pushing a trapezoidal cardboard in the languid interstice. Press with even pressure the under lip with the burnisher or the voicing lance against the paper. Make different cardboards for a wide range of thicknesses and sizes to voice the pipes. With a round rod 4 mm Ø from the foot the languid can be pushed higher. Aim the rod straight left and right next to the place where it is soldered on to the wall.

Good response and good sound:

The pipe is good as it produces the tonic at a normal wind pressure and jumps to a higher octave when the wind pressure is much higher.

Slow:
The pipe starts with random tones and produces the tonic only with a much higher pressure. If the tonic even at a strong pressure doesn’t jump an octave the pipe is too slow.

Fast:
The tonic can be heard with a low wind pressure instantly and sounds with just a slightly higher pressure immediately an octave higher.

Nederlands
   Duits
Principal

Increase foot opening:
the sound is louder and sharper, the sound comes quickly, can sound forced and the tone becomes higher. The speech is sharp, noise and rustling

Reduce foot opening:
the sound comes slower, mellow tone, with fewer overtones, the pitch is lower. The response is weaker, noise, hissing sounds

Push upper lip inward:
Response slower, less overtones, the sound is more dull

Pull upper lip outward:
Response faster, more overtones, the sound has more clarity

Languid higher:
Response slower, more Principal sound, something louder

Languid lower:
Response faster, more tonic sound, flute sound, sound is more aggressive

Languid interstice thinner:
Sound has a dry sharpness, less noisy, the response is faster

Languid interstice wider:
Sound has a raw and aggressive sharpness, louder, more clarity, the response is slower

Increase mouth:
Tonic sounds better, flute-like and slower, after adjusting the air blade the response is more aggressive, chiff, less noise

Reduce mouth:
Sharper, more Principal sound and faster, after adjustment of the air blade the response is more dull,

Foot opening and languid interstice wider plus languid lower or upper lip forward:
Louder, something raw and aggressive sharpness

Foot opening and languid interstice narrower plus languid higher or upper lip inward:
Slow, pretty dry sharpness

Stopped pipes

Stopped pipes react differently on changings of the languid interstice, core location of the languid and upper lip. See the same reactions as with open pipes plus the properties of the stopped pipes. 

Upper lip inward:
Quintiger and colored, response clear and aggressive

Upper lip outward:
Tonic stronger and less overtones, the response is faster and smoother

Languid interstice wider:
Raw and aggressive sharpness, louder, more clarity, the response is slower

Languid interstice thinner:
Dry sharpness, less noisy, diffuse, the response is faster

Languid higher:
Slower, sharper, more Principal sound, little louder, response duller and more volume

Languid lower:
Faster, tonic stronger, flute-like sound, slower, the response is more aggressive

To find the best setting of the languid and the upper lip, it is well to remove the stop and blow the open pipe. The languid must be placed so low that the pipe produces a sound at high wind pressure.

Disturbances and Corrections

Principals pipes

Too slow:
Increase foot opening, examine languid interstice and and see if it is too thin or just too wide if the the foot opening is too narrow. Try the setting of the languid and upper lip by blowing the pipe. Compare the mouth opening with the adjacent pipes

Too loud:
Reduce foot opening, compare languid interstice with the adjacent pipes, may be thinner

Overturns in a higher octave:
Languid higher, press upper lip inward

Too slow:
Languid lower, pull upper lip outward

Raw and rustling:
Languid interstice has impurities. Control position of the languid, the upper lip and the under lip. Make languid interstice thinner. Compare foot opening and languid interstice with the adjacent pipes. Compare mouth opening and attach stitches in the languid

Stopped pipes

Quintig, scrapes, rustles:
Languid lower, pull upper lip outward, make languid interstice thinner, increase foot opening, set languid stitches, increase mouth

Rushes, soft response:
Languid higher, press upper lip, make languid interstice wider, reduce foot opening, rub languid stitches to close them