Q: Bluetooth speaker makes mouse, keyboard and audio stutter

Mouse and keyboard connected to a top spec macbook pro mid-2014. Works fine. When I turn on a bluetooth speaker sometimes it will make all bluetooth accessories turn on/off every second, so the mouse stutters across the screen, the keyboard misses keys or keeps keys held down, and the audio is playing on/off every second.

I would have thought that oh, the mac simply can't handle 3 bluetooth devices... but sometimes it works fine and other times it does this stuttering, so I have no idea. Are there different frequencies of bluetooth and the mac is simply not giving each device its own one? And hence interference?

Any ideas greatly appreciated.

Ben