Stretched tuning

Under stretching or spreading, Eng. stretch- tuning, is a technique for tuning of stringed instruments, especially pianos.

In piano voices, the temperature is initially placed, usually in the form of a circle of fifths from the tone a1, then you tune in octave up and down. Here, the octave " stretch ", that is, the upper tones are higher, the lower tuned down, as if they were purely mathematical.

Although the basic vibration of the strings is "false ", the human ear hears beatless low or zero octaves. This is due to the fact that the harmonics that make up a large part of the sound of a string, only with an "ideal string ", which is infinitely thin and infinitely long, the calculated ideal ( 1:2, 1:3, 1:4 etc. ) would correspond. The rigidity of the real strings exerts However, in addition to mechanical stress a force on the strings and thus increases the frequency of the harmonics (the higher, the more ) - the sound is higher. At extremely short and thick strings, this effect is so strong that they already sound itself unclean and are virtually unstimmbar. This phenomenon is referred to as inharmonicity.

The degree of stretching depends therefore on the strings; the stiffer the string is, the more the octave is stretched. A long concert grand piano ( with relatively long and therefore less thick bass strings ) you stretch the octaves much less than at a low upright piano. In a harpsichord, with its thin strings octaves are practically not stretched.

The degree of stretch determined to be the human ear and not the electronic tuner, which upon the application of different types of moods, however, is a very valuable help. The extension concerns the whole instrument, in the deepest bass and upper treble more, less in the middle.

In order to approximate to real pianos sometimes electronic instruments are " out of tune " in this way, although the fact is superfluous in its kind of tone.

Inharmonicity can also help to disguise small mood disorders in a similar way as it does the vibrato with other instruments and singers.

• Piano
• Mood ( music)