The floor of the Cochlea has the Basilar Membrane on which are four rows of hair cells.
The vibrations, generated by the third ossicle, set up waves in the fluid which proceed to the back of the room (top of the snail shell), down the stairs, and to the front oval window of the room below.
The floor that separates these rooms is hard (bone tissue) except for a long strip that runs lengthwise up the side. The consistency of this strip is reminiscent of a trampoline. It is called the Basilar Membrane.
In the top classroom, there are four rows a chairs that occupy the area we are calling the Basilar Membrane. If you imagine students sitting in these chairs (with scuba gear, of course), these would be analogous to the four rows of hair cells in the Cochlea.
In our model there might be space for each row to be 40 chairs deep each. In the Cochlea, however, the depth would number in the thousands.