In this paper methods for determination of perceptual quality of speech transmission and speech enhancement systems are discussed. The rating categories introduced in the listening test (7.) are not meant to replace existing "objective" or "technical" measures. They are meant to complement the description of a device under test and place more emphasize on the end-users impression of the system.
The rating categories introduced in this paper are complete and intuitive, even non-experts can understand their importance for successful and agreeable speech communication. Benchmark tests using these categories are much more informative for the non-expert and can still be presented "at a glance".
Furthermore, the comparison ratings serve to clarify the responsibility for quality losses, which the device under test cannot avoid, since their origin lies in the mobile network.