To add more details. I run a yamaha avr with a simple 3.1 system. the sub is powered by a TBI sub amp and cross over which has the power switch on the rear and is diffcult to turn on and off. I would normally just leave it powered on, but i had to have the amp; repaired a few years ago after leaving it on continuously.
So i would just like the sub amp to switch on when i turn on the avr. I would put everything in a manual power strip and turn it off manually but my kids would forget and leave it on..