Main speakers cut out when sub powered on


I'm seeing this weird phenomenon. I have connected my Velodyne SPL 800 II sub using it's high level (speaker) inputs. The main speakers and the sub connections share the same speaker binding posts.

If I have the music already playing, and I flip the master switch on the sub, the main speakers cut out for a very brief time (less than a second) and come back on. Is this normal?

The problem wont show up if I leave the sub on "Auto On" mode where it comes to life when it senses signal on the input.

Just not sure what's causing this behavior and probably affecting the amp and/or speakers.

Thanks in advance.
Do you have your speaker cables going from your integrated amp to the speaker cable binding posts on the sub; and then running speaker cables from the binding posts on the sub going to the speakers? Or do you have both pairs of speaker cables sharing the same binding posts on the back of your integrated amp and then connect them to each directly?
Hi Zd

I have the main speaker cables and the sub cables sharing the same binding posts on the integrated i.e. connected in parallel.
I think,
The Auto On circuit presumably brings up the other circuits in the sub, including the high power amplifier circuits, in a more controlled manner, because that is what it is designed to do.

Your sub contains a 1,000 watt Class D amplifier. From a technical standpoint my instinct would be to avoid turning a high powered component like that either on or off while a signal is going into it.
And please refer here: