NTi Audio

Select Newsletter:
Subscribe to Newsletter:

View this as web page

The XL2 Acoustic Analyzer offers Speech Intelligibility (STIPA) measurements according to the latest IEC standard for verifying speech intelligibility of voice evacuation systems. New XL2 features, like averaging multiple STIPA results and ambient noise correction further increase measurement efficiency. This allows acoustic consultants and installers to emulate crowded conditions while measuring STIPA onsite in an empty room, and immediately see the effect that the crowd noise has on the STI values.

All Relevant Standard Editions Supported

The XL2 firmware Version 2.50 measures STIPA according to the IEC 60268-16 (2011, edition 4.0) standard for verifying speech intelligibility of voice evacuation systems. IEC editions 2.0 (1998) and 3.0 (2003) are also supported. Both STI (Speech Transmission Index) and CIS (Common Intelligibility Scale) values are provided.

Ambient Noise Correction

Ambient noise created by the public influences the speech intelligibility. Measuring this speech intelligibility while the public is present, e.g. train stations or airports, is often not feasible because the STIPA measurement requires that a dedicated test signal be played repeatedly through the PA system at the announcement level, which would be annoying to the public. In such circumstances the recommended process is:

First measure the typical or worst case ambient noise during day time.

Then later when the venue is empty (at night for example) play the STIPA test signal and measure the speech intelligibility. The XL2 Analyzer corrects the STIPA result automatically with the ambient noise that was measured earlier and provides speech intelligibility values that can be expected with crowds present. The PA system can then be optimized for better speech intelligibility as required.

In this manner the XL2 Analyzer provides speech intelligibility values at realistic emergency conditions. This is important, as voice evacuation systems with good speech intelligibility may help to save lives.

Averaging Multiple STIPA Measurements

The standard IEC60268-16 recommends taking the average of three or more subsequent measurements at the same location. Multiple measurements increase accuracy and the reliability of the readings. The XL2 Analyzer offers such averaging of STIPA results, calculating both the arithmetic mean value and the statistical deviation.

Download the X2 firmware V2.50 at http://my.nti-audio.com.
Read more about speech intelligibility in the application note.
Guideline “How to Commission an Installed Sound Environment”

NTi Audio Logo
Also in this newsletter

STIPA Reporting Tool


You are welcome to meet NTi Audio at the following events:

29 - 31 Jan. 2013 
ISE 2013 
Booth # 1F117
Amsterdam, NL


STIPA Reporting Tool

The STIPA Reporting Tool creates measurement reports according to the IEC 60268-16 and VDE0833 standards.

Import the data directly from your XL2 including the ambient noise measurements. The corresponding speech intelligibility STI or CIS values are shown.

STIPA Reporting Tool

(Click to enlarge)

Login to My NTi Audio and download the STIPA Reporting Tool at the XL2 support website.

unsubscribe | update my profile | NTi Audio Homepage
© 2012 NTi Audio AG, 9494 Schaan, Liechtenstein