I can't give an EXACT answer just my opinion. I upgraded 10 to 11 a couple of years back. During that same time I installed several bios updates. I don't use usb speakers but some of my external drives that had given no problems started giving me hell at every restart. I would always have to unplug and plug them back in. I think it's something to do with the way 11 and/or the bios handles power & sleep. I solved my issue by installing a powered usb hub for all my devices.
If per chance your speakers are plugged into a usb 2.0 port, see if using a 3.0 port makes any difference. 3.0 has more power.
You might also go into device manager, right click each of your usb controllers>properties>power management tab. Uncheck box that allows computer to turn of the device to save power.
