NTi Audio says a firmware update to its XL2 Analyzer offers on-site measurement of commonly used noise curves according to ANSI and ISO standards. The curves are visualized and presented with the final noise criterion and other relevant information.
“Noise curve standards are used to objectively rate the noise level and thus the acoustical quality of a room or environment,” the company notes. “The XL2 Noise Curve measurements provide numerical and graphical measurement results for Noise Ratings (NR) in accordance with ISO 1996; Noise Criteria (NC) in accordance with ANSI 12.2-2008 and its legacy version of 1995, as well as Preferred Noise Criterion (PNC) and Room Noise Criterion (RNC) curves. The Speech Interference Level (SIL) and Room Criteria (RC) curve rating is also calculated in parallel.”
The XL2 retains relevant measurement values in its memory, allowing the user to switch between the measurement standards after completion of the acquisition without being forced to reacquire the measurement data. Results can be stored on the internal SD card and later integrated into user reports. They contain the applicable noise curve data and the frequency band with the highest noise band value, as well as the averaged spectrum.
The company says measurement and documentation of noise criteria is a frequent task for an acoustic consultant. It quoted CEO Philipp Schwizer as saying, “In the past the calculations for some or all different curves had to be done off-line with a PC-based Excel tool. With the current implementation the user can obtain and document all relevant noise curve data for various international standards directly on the instrument, saving a lot of time and greatly increasing efficiency.”