Sennheiser's are wireless. Bose are bluetooth. Sennheiser is like wearing
a walkie talkie on your head.
Wireless audio devices that come with a "base" have a longer range because the radio uses DECT, not Bluetooth. It's the same technology used in cordless landline phones.
I know visualization "breaks the rules", but it's awfully hard to ignore a walkie talkie on someone's head!