# Statistical guideline factor

The **statistical directivity factor** _{ st} (gamma) (also called **directivity deviation factor** or **statistical directional ****factor** ) is one of the variables used in acoustics to describe the directional characteristic of a sound source . It is defined as the ratio of the effective value of the sound pressure in a certain direction of radiation and distance to the effective value of the sound pressure averaged over all radiation directions at the same distance:
_{}

- .

The statistical directivity factor is therefore dependent on the direction of radiation, values> 1 stand for preferred radiation directions.

In an analogous manner, *receivers* for sound such. B. microphones , specify a statistical directivity factor.

The **degree of directivity** is the square of the statistical directivity factor, the **directivity** or **directivity** is the corresponding dimension with the auxiliary unit of measurement decibel :

## See also

## literature

- Michael Dickreiter, Volker Dittel, Wolfgang Hoeg, Martin Wöhr, “Handbuch der Tonstudiotechnik”, 7th completely revised and expanded edition, published by the ARD.ZDF medienakademie, Nuremberg, 2 volumes, publisher: KG Saur, Munich, 2008, ISBN 3-598-11765-5 or ISBN 978-3-598-11765-7

## Web links

- Statistical guideline factor as DEGA recommendation 101 (PDF file; 1016 kB)