Yamaha Nexo NXAMP4X4 User Manual page 59

INSTALLATION RECOMMENDATIONS
If the MAIN SYSTEM phase reading appears to be superior to the SUB phase reading, then
MAIN SYSTEM will have to be delayed with a value close to the one given by the
geometrical alignment.
If SUB appears to be in advance to MAIN SYSTEM, then SUB will have to be delayed with a
value close to the one given by the geometrical alignment.
Phase alignment can be considered as correct when phase is coincident over the entire
overlapping range (typically an octave from 60 Hz to 120 Hz), and when the overall
response is always superior to SUB's and MAIN SYSTEM's individual response.
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