Styles of
Portative Organs
Range of tone
The instruments of the gothic have a range of tone of approximately 2 to 2 1/2 octaves in 2’, starting approximately with c1. Later, towards the end of the 15th century, larger instruments with a range of about 2 octaves, beginning at f0 or g0, could be found
Dimensions
The height of the organetto´s frame resulting from the 2’-pipes is approximately 80 or 90 cm; the width of the keyboard, and therefore that of the frame is approximately 40 cm.
The depth of the instrument varies slightly more. The keyboard can be positioned in front of the frame in full key-length, or it can be off-set to the back underneath the pipes; this is the kind we prefere. Together with the bellows that is mounted on the back, the resulting depth is approximately 17 - 28 cm.
Frame
Most of the time, all pipes are lined up side by side in up to 2 rows (up to 3 in rare cases). Existing additional drone-pipes are sometimes grouped into a Drone tower which gives the instrument an almost cathedral-like appearance.Pipes
In most illustrations, the pipes are positioned in two rows with one row behind the other. They are generally made of metal in historic portatives. Initially made of soft lead, over time a lead-tin alloy with a high lead content became the preferred choice for pipes. Although lead gives the pipes a beautiful and soft sound, it makes them mecanically very soft so that nowadays a common choice is an alloy with a high tin content; it increases the mechanical stability without rendering the sound overtone.
Starting in the 15th century, the use of wooden pipes became more and more popular in organ building. For my instruments, I also like to use wooden pipes as a popular alternative to the metal pipes.
The advantage of wooden pipes is that they produce a warm sound while giving the instrument a high mecanical stability. This is especially important for portable instruments.
Bellows
Mainly with 4-7 pleats and made of wood and leather, the bellows supplies the necessary air to the instrument. It is mounted on the back of the instrument and expands upwards.
The air pressure, produced by compressing the bellows downwards is enough for longer phrases. This is an important characteristic of the portative organ; the musician has direct influence on the air pressure and therefore on the sound and the dynamic of the play.
Keyboard
By pushing down the keys, the corresponding pipe-valve opens, which supplies air to the corresponding pipes through the wind channels. It is more practical for portatives to have the keys large enough for easy play, but small enough to result in a small instrument with a wide range of tones. The advantage of narrower keys is that a wide range of tones can be achieved; this is an advantage for the drone-changing using the thumb.
Positioning
While the right hand is playing, the left hand is using the bellows. Numerous illustrations show the instrument being played in the sitting position and placed on the left thigh; other illustrations show the instrument being played in the standing position while it is being carried by means of a shoulder strap or a piece of cloth.