scope:

The present document describes auditory and instrumental testing methodologies, which can be used to evaluate the perceived listening effort in the following speech communication scenarios at acoustical interfaces in the presence of acoustical near-end ambient noise.

Similar to other instrumental quality prediction methods like e.g. ETSI TS 103 281 [4] or Recommendation ITU-T P.863 [i.2] valid objective predictions can only be made based on a specific listening test design and on auditory results obtained in such tests.

The present document specifies the test design and reference conditions used to evaluate listening effort subjectively.

The objective prediction model specified are based on this test design and validated against the results of the underlying subjective tests; only normal hearing listeners are considered. The usage for hearing impaired listeners is for further study.

Several application scenarios and types of terminals are covered:

• (Mobile) Handset.

• In-car communication systems.

The following applications are for further study:

• Headset (including active noise cancelling devices).

• Group audio terminals.

• Mobile handheld hands-free.

• Vehicle hands-free.

• Fixed, mobile and IP-based networks (including impairments).

Binaural as well as monaural recording situations are covered. The listening effort prediction model utilizes binaural signals for acoustical recordings and monaural signals for electrical recordings.