### Abstract

Possibilities to apply spectrumindex in building
acoustics are studied. As
usually, spectrumindex refers to the difference of two
sound pressure
levels caused by the same sound field and measured using
two separate
frequency weightings (A- and C-weighting). The purpose of
the study is to
develope a simple method in which one can apply the
spectrumindex to
evaluate the traffic noise reduction indices existing
already in a
NORDTEST-method. Some difficulties in that method, i.e.
its definitions,
used spectra and the extensive datamaterial, are
discussed too. Further, the
spectrumindex principle has been applied to a
testmaterial of 20 different
windows. Two alternatives have been used as basic sound
reduction
indices, one for pink noise and the other for a traffic
noise spectrum
modified from the spectrum given in the French standard
NF S 31-051.
Three different equations were tested in estimating the
reduction index for
other spectra for which only the spectrumindex is known.
Finally, the
equation including the best realizable sound insulation
curves has been
chosen as the most feasible estimation method. It has
been shown, that by
accepting some little limitations concerning the noise
spectra and
magnitude of spectrumindex, one can get very reliable
estimation results.
In general, the deviation will be at the most 1 dB from
the correct value
calculated in accordance with the NORDTEST-method. This
may be seen
important also therefore, that instead of the 32
different numbers needed
traditionally, here only three are necessary in
calculating the noise
reduction index. The study has been finalized by using a
Greek material
consisting of 11 exterior doors and one single pane
window.

Original language | English |
---|---|

Place of Publication | Espoo |

Publisher | VTT Technical Research Centre of Finland |

Number of pages | 42 |

ISBN (Print) | 951-38-4227-4 |

Publication status | Published - 1992 |

MoE publication type | Not Eligible |

### Publication series

Series | VTT Publications |
---|---|

Number | 109 |

ISSN | 1235-0621 |

### Keywords

- buildings
- acoustics
- sound waves
- noise reduction
- acoustic measurement
- estimating
- utilization
- sound pressure
- calculations
- methods
- spectra
- indexes (ratios)
- windows
- doors
- evaluation
- Spectrumindex

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## Cite this

Parmanen, J., & Sysiö, P. (1992).

*Study on the possibilities to apply spectrumindex*. VTT Technical Research Centre of Finland. VTT Publications, No. 109