A small hemi-anechoic chamber was constructed to.facilitate sound-power measurements by the point-to-point intensity technique and ISO Draft Standard 9614 was followed to validate a test procedure and qualify results. The Jacility is described and simple schemes are presen ted for the validat ion a
A SUPPLEMENT OF SOUND MEASUREMENT TECHNIQUE BY AN ONLINE QUALITY TEST PROCEDURE FOR THE INDICESLEQ AND LX%
✍ Scribed by A. HEISS
- Publisher
- Elsevier Science
- Year
- 2001
- Tongue
- English
- Weight
- 362 KB
- Volume
- 241
- Category
- Article
- ISSN
- 0022-460X
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✦ Synopsis
As is well known every measured sound index like ¸CO and ¸x% has limited accuracy due to the usually occurring stochastic level #uctuations. This limitation can be taken into account adequately by calculating the con"dence limits from the signal's microstatistic structure. The basic theory and its preconditions close to measurement practice have been established formerly by the author. An overview is given here. The method provides to work quality controlled in a #exible way. A PC-software for online performance is now available. Tested by "eld measurements this technique is applicable on the quality-monitored short-term separation of level components of di!erent sound sources in the outdoor environment. The "nal results are the ¸CO of the source of interest, the con"dence limits of the ¸CO and its resolution level. Resolution limits down to 10 dB below the residual sound level are practicable. This kind of application has already been introduced and used in Germany to some extent. At the present state of the art the tool also can be applied on sound transfer measurements, especially with relatively high background level in a receiver room, and on examining the in#uence of a small absorption model area for in-room damping, to be extended later to full scale.
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