At a low setting, the SoundBed's vibrations are fairly inaudible in the room and the translation through walls or the floor is minimal.
At a high setting, SoundBed's vibrations are audible in the room and can be translated through the floor. In a room with ambient sound like an air conditioner running, music playing, or talking, the low frequencies are noticeable but not necessarily disruptive, even at a higher setting.
Generally the ambient noise depends on two main factors:
1) Acoustics In The Room
2) Floor Material
The greatest potential for disturbance is through wood floors. Depending on the frequencies being played, at a high setting a low rumbling could potentially be heard by downstairs neighbors. With concrete floors, this is generally a non-issue.
Placing SoundBed on a rubberized mat will dampen this effect considerably if not eliminate it. There are a variety of options on Amazon such as this mat.