Influences of external error sources on measurements of room acoustic parameters / Martin Guski.

Format:

Book

Author/Creator:

Guski, Martin, author.

Language:

English

Subjects (All):

Noise control.

Physical Description:

1 online resource (176 pages) : illustrations

Edition:

1st ed.

Place of Publication:

Berlin, Germany : Logos Verlag Berlin, [2015]

Summary:

Correct and precise measurements of room acoustic parameters are of fundamental importance for subjective room impression characterization and for the physical description of the sound field. This thesis investigates external influences on acoustic measurements and errors of the resulting room acoustic parameters.Theoretical models have been developed to predict these errors and indicate the tolerable limits of the described influences. To validate these models, specially designed room acoustic measurements that separate the individual influence factors have been conducted.Noise has been identified as one of the main influence factors and occurs during every measurement. In this thesis the performance of five commonly used stationary noise compensation methods are systematically analyzed depending on the peak signal-to-noise ratio. Impulsive noise that could also occur during the measurement is investigated separately, as the previously introduced compensation techniques are unsuited to handle the influence.The second part of this thesis analyzes the influence of time variances during measurements. Inter- and intra-measurement temperature changes, air movement, and human-sized scattering objects have been investigated.

Contents:

Intro

1 Introduction

1.1 Objective

1.2 Outline

2 Fundamentals

2.1 Measurement Theory

2.1.1 Room Acoustic Measurements

2.1.2 Measurement Chain

2.1.3 Excitation Signal

2.2 Acoustic Theory

2.3 Room Acoustic Parameters

2.3.1 Reverberation Time

2.3.2 Sound Strength

2.3.3 Energy Ratios

2.4 Assessment of Error Size

3 Noise Compensation

3.1 Noise Compensation Methods

3.1.1 Method A: Full Impulse Response

3.1.2 Method B: Truncation at Intersection Time

3.1.3 Method C: Truncation and Correction

3.1.4 Method D: Subtraction of Noise

3.1.5 Method E: Truncation, Correction, and Subtraction

3.2 Evaluation Approaches

3.2.1 Model Approach

3.2.2 Measurement Approach

3.3 Comparison of Noise Compensation Methods

3.3.1 Reverberation Time

3.3.2 Clarity Index

3.3.3 Sound Strength

3.4 Summary of Noise Compensation Methods

3.4.1 Random Errors

3.5 Further Influences

3.5.1 Implementation of Correction for Truncation

3.5.2 Excitation Signal

3.6 Conclusion

4 Impulsive Noise Detection

4.1 Theory

4.2 Detection of Impulsive Noise

4.2.1 Proposed Detection Algorithm

4.3 Experimental Validation

4.3.1 General Assembly Hall

4.3.2 Ordinary Room

4.4 Summary and Conclusion of Impulsive Noise

5 Time Variances

5.1 Air Movement

5.1.1 Measurement Setup

5.1.2 Analysis of Measurements

5.1.3 Statistical Summary

5.1.4 Discussion

5.2 Inter-Measurement Temperature Changes

5.2.1 Eurogress Measurements

5.2.2 Assembly Hall Measurements

5.2.3 Detailed Analysis of Clarity Index

5.2.4 Summary

5.2.5 Conclusion

5.3 Intra-Measurement Temperature Changes

5.3.1 Measurement Setup

5.3.2 Analysis

5.3.3 Summary

5.3.4 Conclusion

5.4 Person Scatter

5.4.1 Measurement Setup

5.4.2 Analysis

5.4.3 ANOVA

5.4.4 Summary.

5.4.5 Conclusion

6 Conclusion and Outlook

A General Assembly Hall

B Noise Compensation Methods

B.1 Systematic Error

B.2 Random Error

C Inter-Measurement Temperature Change.

Notes:

Description based on print version record.

ISBN:

3-8325-9436-1