Balanced Noise Criteria (NCB) curves are used to specify acceptable background noise levels in occupied spaces and include noise from air-conditioning systems and any other ambient noise. They are intended to replace the NC curves.

噪声标准曲线(NC curves)是白瑞纳克(L．L．Beranek)在1 957年根据三百名工作人员的调查而发表的，用于评价空间噪声。 对于一个给定的噪声等级，每一条曲线规定了倍频带最大声压级。

Strutt|Criteria|Curves|Sound Level|NCB inserts the Balanced Noise Criterion (NCB) curve into the current row of the worksheet. The NCB curve is intended as an improvement of the base NC curve to improve its subjectively 'rumbly' and 'hissy' characteristics at …

1989年8月1日 · The NCB curves are used (1) before construction, to specify acceptable octave‐band noise levels, and (2) after construction, to rate the noise as to its effect on speech communication; as to any spectral imbalance (e.g., rumble or hiss), including how many decibels of noise reduction are needed in each octave band to eliminate spectral ...

2023年2月9日 · Balanced Noise Criterion [NCB]: The new Balanced Noise Criterion curves, updated in ANSI S12.2-2008, accounts for sound frequencies down to 16 Hz, which will address issues from the low-frequency hum of energy efficient HVAC equipment. NCB also reduces the higher frequency levels to eliminate hiss.

Comparing Noise Criterion (NC, NCB, RNC) to Noise Rating (NR) and dB (A). An online Noise Rating (NR) calculator. The Noise Rating (NR) Curve used to determine acceptable indoor environments for hearing preservation, speech communication and annoyance. A noise measurement system for continuous or ambient noise in indoor environments.

Comparing Noise Criterion (NC, NCB, RNC) to Noise Rating (NR) and dB (A). In Europe it is common to use Noise Rating Curves - NR. dB (A) - LA - is a weighted method compensating for the human hearing of sound pressure at different frequencies. Choosing appropriate noise criteria is important when specifying acceptable levels of noise.

Defines four sets of criteria for evaluating room noise: (1). Balanced noise-criterion (NCB) curves, (2). Room-criterion (RC) curves, (3). Criteria for acoustically-induced vibrations, and (4). One-third octave band hearing threshold curves.

Download scientific diagram | (a) NC curve (b) NCB curve from publication: Research Progress of evaluation method and control limit for Substation low frequency noise | At present, the low...

2018年9月27日 · Noise Criteria is calculated by measuring the background noise is a building using a 1/1 octave spectrum and plotting the spectrum along with a set of curves, called NC Curves, ranging from 63 Hz to 8000 Hz. Noise Criteria for a specific measurement is defined as the criteria of the lowest NC Curve which is not exceeded by the noise spectrum.