Measurement with verification of stationary signals and noise in extremely quiet environments: Measuring below the noise floor

Roger M. Ellingson, Frederick Gallun, Guillaume Bock

Research output: Contribution to journalArticle

Abstract

It can be problematic to measure stationary acoustic sound pressure level in any environment when the target level approaches or lies below the minimum measureable sound pressure level of the measurement system itself. This minimum measureable level, referred to as the inherent measurement system noise floor, is generally established by noise emission characteristics of measurement system components such as microphones, preamplifiers, and other system circuitry. In this paper, methods are presented and shown accurate measuring stationary levels within 20 dB above and below this system noise floor. Methodology includes (1) measuring inherent measurement system noise, (2) subtractive energy based, inherent noise adjustment of levels affected by system noise floor, and (3) verifying accuracy of inherent noise adjustment technique. While generalizable to other purposes, the techniques presented here were specifically developed to quantify ambient noise levels in very quiet rooms used to evaluate free-field human hearing thresholds. Results obtained applying the methods to objectively measure and verify the ambient noise level in an extremely quiet room, using various measurement system noise floors and analysis bandwidths, are presented and discussed. The verified results demonstrate the adjustment method can accurately extend measurement range to 20 dB below the measurement system noise floor, and how measurement system frequency bandwidth can affect accuracy of reported noise levels.

Original languageEnglish (US)
Pages (from-to)1164-1179
Number of pages16
JournalJournal of the Acoustical Society of America
Volume137
Issue number3
DOIs
StatePublished - Mar 1 2015
Externally publishedYes

Fingerprint

adjusting
sound pressure
rooms
bandwidth
preamplifiers
rangefinding
hearing
microphones
methodology
thresholds
acoustics
Sound
energy
Hearing
Methodology
Acoustics
Energy

ASJC Scopus subject areas

  • Acoustics and Ultrasonics
  • Arts and Humanities (miscellaneous)

Cite this

Measurement with verification of stationary signals and noise in extremely quiet environments : Measuring below the noise floor. / Ellingson, Roger M.; Gallun, Frederick; Bock, Guillaume.

In: Journal of the Acoustical Society of America, Vol. 137, No. 3, 01.03.2015, p. 1164-1179.

Research output: Contribution to journalArticle

@article{fed60b9b6c404f739cef28c1f70dae7e,
title = "Measurement with verification of stationary signals and noise in extremely quiet environments: Measuring below the noise floor",
abstract = "It can be problematic to measure stationary acoustic sound pressure level in any environment when the target level approaches or lies below the minimum measureable sound pressure level of the measurement system itself. This minimum measureable level, referred to as the inherent measurement system noise floor, is generally established by noise emission characteristics of measurement system components such as microphones, preamplifiers, and other system circuitry. In this paper, methods are presented and shown accurate measuring stationary levels within 20 dB above and below this system noise floor. Methodology includes (1) measuring inherent measurement system noise, (2) subtractive energy based, inherent noise adjustment of levels affected by system noise floor, and (3) verifying accuracy of inherent noise adjustment technique. While generalizable to other purposes, the techniques presented here were specifically developed to quantify ambient noise levels in very quiet rooms used to evaluate free-field human hearing thresholds. Results obtained applying the methods to objectively measure and verify the ambient noise level in an extremely quiet room, using various measurement system noise floors and analysis bandwidths, are presented and discussed. The verified results demonstrate the adjustment method can accurately extend measurement range to 20 dB below the measurement system noise floor, and how measurement system frequency bandwidth can affect accuracy of reported noise levels.",
author = "Ellingson, {Roger M.} and Frederick Gallun and Guillaume Bock",
year = "2015",
month = "3",
day = "1",
doi = "10.1121/1.4908566",
language = "English (US)",
volume = "137",
pages = "1164--1179",
journal = "Journal of the Acoustical Society of America",
issn = "0001-4966",
publisher = "Acoustical Society of America",
number = "3",

}

TY - JOUR

T1 - Measurement with verification of stationary signals and noise in extremely quiet environments

T2 - Measuring below the noise floor

AU - Ellingson, Roger M.

AU - Gallun, Frederick

AU - Bock, Guillaume

PY - 2015/3/1

Y1 - 2015/3/1

N2 - It can be problematic to measure stationary acoustic sound pressure level in any environment when the target level approaches or lies below the minimum measureable sound pressure level of the measurement system itself. This minimum measureable level, referred to as the inherent measurement system noise floor, is generally established by noise emission characteristics of measurement system components such as microphones, preamplifiers, and other system circuitry. In this paper, methods are presented and shown accurate measuring stationary levels within 20 dB above and below this system noise floor. Methodology includes (1) measuring inherent measurement system noise, (2) subtractive energy based, inherent noise adjustment of levels affected by system noise floor, and (3) verifying accuracy of inherent noise adjustment technique. While generalizable to other purposes, the techniques presented here were specifically developed to quantify ambient noise levels in very quiet rooms used to evaluate free-field human hearing thresholds. Results obtained applying the methods to objectively measure and verify the ambient noise level in an extremely quiet room, using various measurement system noise floors and analysis bandwidths, are presented and discussed. The verified results demonstrate the adjustment method can accurately extend measurement range to 20 dB below the measurement system noise floor, and how measurement system frequency bandwidth can affect accuracy of reported noise levels.

AB - It can be problematic to measure stationary acoustic sound pressure level in any environment when the target level approaches or lies below the minimum measureable sound pressure level of the measurement system itself. This minimum measureable level, referred to as the inherent measurement system noise floor, is generally established by noise emission characteristics of measurement system components such as microphones, preamplifiers, and other system circuitry. In this paper, methods are presented and shown accurate measuring stationary levels within 20 dB above and below this system noise floor. Methodology includes (1) measuring inherent measurement system noise, (2) subtractive energy based, inherent noise adjustment of levels affected by system noise floor, and (3) verifying accuracy of inherent noise adjustment technique. While generalizable to other purposes, the techniques presented here were specifically developed to quantify ambient noise levels in very quiet rooms used to evaluate free-field human hearing thresholds. Results obtained applying the methods to objectively measure and verify the ambient noise level in an extremely quiet room, using various measurement system noise floors and analysis bandwidths, are presented and discussed. The verified results demonstrate the adjustment method can accurately extend measurement range to 20 dB below the measurement system noise floor, and how measurement system frequency bandwidth can affect accuracy of reported noise levels.

UR - http://www.scopus.com/inward/record.url?scp=84925232738&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84925232738&partnerID=8YFLogxK

U2 - 10.1121/1.4908566

DO - 10.1121/1.4908566

M3 - Article

C2 - 25786932

AN - SCOPUS:84925232738

VL - 137

SP - 1164

EP - 1179

JO - Journal of the Acoustical Society of America

JF - Journal of the Acoustical Society of America

SN - 0001-4966

IS - 3

ER -