Noise Curves

Noise Curves

Noise curves specify the acoustic ambient noise in an indoor environment. Typical disturbing noises are the background noise caused by an air conditioning system as well as noises from heating or ventilation systems (HVAC).

At a glance

  • Noise Criteria NC
  • Room Noise Criteria RNC
  • Room Criteria RC
  • Noise Rating NR
  • Grenzkurven GK 

Overview

Background noise that is annoying creates fatigue and can negatively affect productivity and safety. Too much noise also affects the ability to communicate, thus the intelligibility of speech. Therefore, standard methodologies for quantifying such noise have been developed. Different rooms, locations, regulations and applications may allow individual acceptable noise ratings. In most cases, the goal is that background noise should not interfere with the purpose of the room, e.g. the noise of an office air-conditioning system should not interfere with telephone calls or conversations.

How to measure and report

Measuring Noise Curves

The XL2 Acoustic Analyzer measures the background noise spectrum of the unoccupied room in accordance with the standard. The resulting frequency spectrum gets classified by the Noise Curves. The noise rating is designated as the value of the highest noise curve “touched” by the measured noise spectrum in 1 dB steps.

This allows a quick verification if the background noise in the room under test meets the specified requirements and shall not annoy people occupying the room. The Noise Curve functionality is optional and requires that the Spectral Limits Option be installed on the instrument.

XL2 Noise Curves

The XL2 indicates the frequency band with the highest noise curve rating between 16 Hz and 8 kHz. Additionally, the instrument calculates also the speech interference level (SIL) result by averaging the octave-band sound pressure levels at 500 Hz, 1000 Hz, 2000 Hz and 4000 Hz.

The XL2 Acoustic Analyzer measures the following Noise Curves:

  • Noise Criteria NC (ANSI/ASA S12.2-2019)
  • Room Noise Criterion RNC (ANSI/ASA S12.2-2019)
  • Room Criteria RC (ANSI/ASA S12.2-2019))
  • Noise Rating NR (ISO/R 1996-1971)
  • PNC Rating (ASA 1971)

Data Analyzing and Reporting

Room Acoustics Reporter offers a dedicated solution for generating standardized noise curve reports. The software calculates the average background noise spectrum in the room. This may be compared with the target range - based on the usage of the room. The measurement data of the following XL2 functions can be imported: SLMeter, Noise Curves, 1/12 Octave and Cinema Meter.

Projector PRO XL View

 

Room Acoustics Reporter supports the following Noise Curve standards:

  • Noise Criteria NC (ANSI/ASA S12.2-2019)
  • Room Noise Criterion RNC (ANSI/ASA S12.2-2019)
  • Noise Rating NR (ISO/R 1996-1971)
  • Grenzkurven GK (DIN 15996:2008)

Configuration

Exel Set for Noise Curves Testing

XL2 Kit for Noise Curves Measurements

including
  • XL2 Acoustic Analyzer
  • Spectral Limits Option for XL2
  • Room Acoustics Reporter 365 (annual subscription service)
  • M2211 Measurement Microphone
  • ASD Cable for XL2
  • Mains Power Adapter
  • Calibration Certificates IEC 61672-3
  • Exel System Case

Get more Information

Contact us for a quotation or to discuss your measurement application.

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