Logitech announced today that its UE Boom 2 and Megaboom speakers are being updated to add support for Google Now voice interactions. To use it, just press the Bluetooth button, and I'll let Engadget's explainer take away the rest:
Just do a quick press of the small Bluetooth button on the top of the speaker and wait to hear the audible prompt, which is the same as when you say "OK Google" or press the microphone icon for voice control on your phone. Both the Bluetooth button and the power button will flash during this interaction. If you're playing music while dropping into voice control functionality, it will pause and listen for your inquiry.