Synthetic soundfields for the rating of spatial perceptions

This paper focusses on new listening tests and their results for the quantities apparent source width (ASW) and listener envelopment (LEV). In these tests, binaurally recorded sound fields are compared to synthetic sound fields. These synthetic sound fields can be fitted in real-time to the sound field under test by the test person. Thus the sound fields under test can be measured absolutely for ASW and in relation to the synthetic sound field in case of LEV. Investigations on the suitability of the synthetic sound fields and test signals for the rating of ASW and LEV have been made. The results of these investigations lead to limits for ASW and LEV as single number quantities for the characterization of sound fields in rooms. For listening tests concerning spatial hearing, binaural recording techniques are state of the art even though different recording and playback techniques led to better or worse localization abilities of the test persons. Therefore recordings from three different artificial heads are compared. Playback with headphones sometimes evoke in-the-head localization and front-to-back inversions which are said to appear less frequent for sound field reproduction via cross-talk-cancellation. In order to examine these influences the listening tests were made with both, equalized headphones and cross-talk-cancellation (CTC) techniques.