Standard output impedance is about 150ohm

In terms of the actual voltage swing output by the unit, if you have on-board content recorded at full scale deflection, then a master volume of:

73% corresponds with the consumer-grade line level of 0.44V-peak aka “-10dBV level”

90% corresponds with the 0dBu reference level of 1.1V-peak

100% corresponds with the professional line level of 1.75V-peak aka “+4dBu level”

Because of these settings, the CUBE audio output is widely compatible in almost any situation.