Cadence Q DRIVE SERIES - Manual (Page 11)

Please note that the minimum impedance load for single
Cadence Q Series amplifiers is 2 ohm stereo and 4 ohm
mono bridged.
Lower impedance loads will cause overheating and may
damage the amplifiers.
Do not mix different type and different impedance
speakers in the series and/or parallel combinations, as
unequal power sharing and acoustic outputs will result.