Battery backup/ surge protector and sleep power cycle on my iMac

I have a simple question regarding whether my iMac is going through a power cycle when asleep. The situation: my iMac and various peripherals are powered through an APC battery backup/ surge protector. The iMac is plugged into the master outlet on the battery backup of course.

I have a set of very good computer speakers which are plugged into the outlets controlled by the master outlet; these power down when the master outlet device (the iMac) goes to sleep. The strange thing is that while iMac is asleep I hear the speakes ocassionally power on (the bass cube makes a noise that indicates this). So it seems there is a powering down and on cycle going. Is this normal? Should I change anything in my setup. APC recommends plugging peripherals (like speakers, which they name specifically) into these controlled outlets to save energy.

It may be that I simply need to contact APC to change the threshold sensitiviy, however, it is currently set to medium (the recommended default).

Thanks for your help.