I got these data
Sony experia z3
Loudspeaker
Voice 69dB / Noise 66dB / Ring 67dB
Audio quality
Noise -86.4dB / Crosstalk -86.6dB
Sony xperia xa ultra
Loudspeaker
Voice 88dB / Noise 79dB / Ring 82dB
Audio quality
Noise -92.9dB / Crosstalk -92.5dB
is not xperia xa ultra better for call quality
Sony experia z3
Loudspeaker
Voice 69dB / Noise 66dB / Ring 67dB
Audio quality
Noise -86.4dB / Crosstalk -86.6dB
Sony xperia xa ultra
Loudspeaker
Voice 88dB / Noise 79dB / Ring 82dB
Audio quality
Noise -92.9dB / Crosstalk -92.5dB
is not xperia xa ultra better for call quality