ETSI TS 103 224

The quality of background noise transmission is an important factor, which significantly contributes to the perceived overall quality of speech. Terminals, networks, and system configurations including wideband, superwideband, and fullband speech services can be greatly improved with a proper design of terminals and systems in the presence of background noise. ETSI TS 103 224:

• describes a sound field simulation technique allowing to simulate the real environment using realistic background noise scenarios for laboratory use;
• contains a database including relevant background noise samples for subjective and objective evaluation.

The present document describes the recording technique used for the sound field simulation, the loudspeaker setup, and the loudspeaker calibration and equalization procedures. Furthermore the document specifies the test room requirements for laboratory conditions.

The simulation environment specified can be used for the evaluation and optimization of terminals and of complex configurations including terminals, networks and others. The main application areas are: outdoor, office, home and car environment.

The setup and database as described in the present document are applicable for:

• Objective performance evaluation of terminals in different (simulated) background noise environments.
• Speech processing evaluation by using the pre-processed speech signals in the presence of background noise, recorded by a terminal.
• Subjective evaluation of terminals by performing conversational tests, specific double talk tests, or talking and listening tests in the presence of background noise.
• Subjective evaluation in third party listening tests by recording the speech samples of terminals in the presence of background noise.