Are you sure the Plantronics is bluetooth? I've never seen bluetooth specs
that claim more than a 10 meter or 30 foot range. I've used bluetooth
headsets for years and I'd have to say that 30 feet is really optimistic!
Add a wall or a corner to the physical setup and it won't be reliable over
even over 30 feet.

There are lots of proprietary wireless headsets using other technologies
that have a longer range. If your headset came with its own single it may
not be bluetooth.

On the other hand I seem to recall that there is a newer bluetooth spec
with enhanced range... help me out someone?