Your USB speakers plugged into an external USB 2.0 hub do not play sound and Device Manager lists them as unknown devices?
Your speakers are NOT fully compatible with the USB 2.0 specification. This causes a 'stall' when the operating system attempts to enumerate them. After multiple 'stall' events, Windows stops trying and the device is marked as unknown.
To workaround this issue, either plug the speakers directly into a USB port on the computer, or unplug / plug them into the external hub until they install correctly.