Summary of S4-260254: Proposed Update to Recording Scenario 3

Main Objective

This contribution proposes updates to recording scenario 3 in the DaCAS (Data Collection for Audio Systems) work to align with recent changes made to 3GPP TS 26.260 through the ATIAS_ph2 work item. The goal is to enable more consistent evaluation of DaCAS example solutions with the specifications in TS 26.260 and TS 26.261.

Background

Recent work documented in S4aA250123 proposed additional sound source angles for evaluating directional information, which led to updates in 3GPP TS 26.260. This contribution proposes reflecting similar changes in the DaCAS recording scenario 3 to maintain alignment between the two specifications.

Proposed Technical Changes to Recording Scenario 3

Sound Source Configuration

• Loudspeaker: High quality loudspeaker complying with clause 4.0.2 in TS 26.260
• Source Signal: British English single talk sequence per ITU-T P.501
• Male and Female speakers
• 20Hz-20kHz frequency range
• 35.4s duration
• -27 dB RMS level
• 48 kHz sample rate, 16-bit depth

Calibration Requirements

• Loudness: 75 dB SPL calibration according to clause 5.5.1 of TS 26.260
• Frequency Response: Equalized spectrum measured at 1m on-axis
• ±1 dB tolerance from 100-200 Hz
• ±0.5 dB tolerance from 200 Hz-20 kHz

Acoustic Environment

• Anechoic chamber (recommended per clause 4.0.3 of TS 26.260) OR acoustically treated room with short reverberation (compliant with ETSI TS 103 224 clause 6.1 or ITU-T BS.1116 clause 8)

Positioning Requirements (Key Changes)

For Hand-held and Headset devices:
- Source distance: 1-1.5m
- Source angles: According to Table 5 in Section 5.6.4.1 of TS 26.260
- Azimuth angles: 0°, ±30°, ±60°, ±90°
- Elevation angle: 0°

For Table-mounted devices:
- Source distance: 0.8-1.5m (aligned with clause 5.4.2.5 for Spatial capture arrangement in TS 26.260)
- Azimuth angles: 0°, ±30°, ±60°, ±90°, ±120°, ±150°
- Elevation angle: 26.6° (per clause 5.4.2.5 in TS 26.260)

Documentation Requirements

• Applied sound source, acoustic environment, and device mounting shall be clearly documented
• Depending on targeted capture capability, a subset of recorded sound source angles may be used for evaluation

Conclusion

The contribution proposes agreement on the updated recording scenario 3 to enable closer alignment between DaCAS evaluation procedures and the test methods specified in the latest release of 3GPP TS 26.260.