BS EN ISO 266:1997

Defines preferred frequencies for acoustical measurements, based on the R10 series of preferred numbers in ISO 3 and reference frequency of 1000 Hz.Does not include frequencies for music, all audiometric frequencies or series other than R10 from ISO 3. Nor does it apply when a constant frequency increment, or other particular spacing would be more suitable, or when the adoption or retention of other frequencies is preferable.

This International Standard specifies preferred frequencies for acoustical measurements. The preferred frequencies are based on the R10 series of preferred numbers in ISO3 and the reference frequency of 1000Hz.

For most acoustical measurements and presentations of data, a frequency spacing based on a constant percentage increment is generally preferred and the test frequencies then form a geometric series. For certain acoustical measurements, a constant frequency increment is a suitable spacing.

The International Standard deals with the geometric series and is not intended to apply to cases where a constant frequency increment, or other particular spacing, would be more suitable, or where there may be good reasons for the adoption or retention of other frequencies.

This International Standard does not deal with:

• frequencies for music;

• all audiometric frequencies;

• series other than R10 from ISO3.