Build-up of flutes

Today's Boehm flutes are made of three pieces: the head joint, the middle joint and lower joint.

The headjoint is the place where the sound of the flute is made. Thus the form of the hole, the material and thickness of the tube of the head are essential for the resulting sound. The plate which is connected to the tube around the side hole, where one has to blow over, is called mouthplate. The piece between the plate and the tube is called "chimney". At the moment most of the moutholes are formed like rectangles with rounded corners. The dimensions are about 12 mm to 10 mm.

There are flutes with C-lower joint and such with H-lower joint. The later ones have one note more at the lower end of the scale and the notes in the upper range are a bit easier to play.

C lower jointH lower joint

Lower joint (C) Lower joint (H)

The keys are all positioned on the middle and lower joint. Both systems are not connected (in contrast to clarinets for example).

A second characteristic of flutes is the position and form of the keys. There are flutes with ring keys and such with closed keys. In case of ring keys the wholes have to be closed with the fingers of the player. Thus the player has to correct the posture of his hands and fingers continually, a good thing for learners. Additionally ring keys make it possible to play quarter-tones and glissandi.

ring keysclosed keys

ring keys closed keys

A second distinctive feature for flutes is the arrangement of the keys. The two alternatives are called offset and inline flutes. With offset flutes the key for playing a G is on a separte axis. Thus the ring finger kann easier close the key. In the picture below you find a inline flute on the left side and an offset instrument on the right.

Comparison of offset and inline flute

Alltogether a flute consists of more than 150 pieces. Those are screws, axes, springs, pads, rings and so on.

Each flute has 16 tone holes. Each of them has a chimney attached to itself. The chimney is kind of a short tube put vertical on the hole. So the key can close a horizontal plane whole.

As the diameter of a tone hole of a modern flute is much bigger than that of a finger tip, the holes are always closed by keys (also for ring keys). To close the holes leak-proof, there are pads inside the keys.

"Conventional" pads are made of felt, strenghened by a thin layer of cardboard. The outer layer is made of a skin, produced from beef bowels.

A more recent development is the thinner "Straubinger pad". This consists of a plastic sag, a very thin felt and a double layer of skin. The closure is built by the plastic.

Straubinger pads are long living. They do not wear continually but will fail, if the skin is ruptured and the felt gets wet and soaks.

The lengths of the joints are 22 cm (head-joint), 35,5 cm (middle-joint) and 13 cm (lower-joint). The diameter of the flute tube is 19 mm. The head-joint is parabolically reduced to 17 mm

A flute made of silver weighs about 560 Gramm. For building flutes mainly Sterling silver (92,5% silver) is used. Pure silver would be too soft. Another alternative is gold (weight: 980 Gramm), mostly in 9, 14 oder 18 Karat.

Another wide spread material mainly for cheaper beginners instruments is German silver, an alloy made of copper, zinc and nickel. This makes it a problem to people with nickel allergy. For those at last a mouth-hole plate made of silver is needed, because the contact to the plate is continually and sweat and saliva amplifies the irritation.

Lately wood is getting popular for building flutes, again. The latest scientific works show, however, that the material has not as much influence on the sound of the flute, as for example Scheck wrote in his book. As the tube of the flute only works as a resonance room, only the weight, the wall thickness and the surface quality have influence. The last of those might lead to additional eddies inside the tube. Main parameter for the sound is the head joint and especially the profile of the mouth hole.

The three pieces of the flute are put together in such a way that the mouth-hole is in line with the first small key of the middle-joint. The lower-joint is turned to put the axis of the lower-joint in the middle of the last keys of the middle-joint.

To take care of the delicate mechanics of the flute, one should care not to put forces on the axes from the side. Thus it is the easiest to hold the middle-joint on the top above the first key and the foot-joint in a way that the fingers just close the keys in a way all forces are aimed in the closing direction of the keys.

Author: Claudia Haider; Last updated 10.04.2013