How much room is there below a sedan's rear seats?

I was thinking about building a subwoofer enclosure beneath the seats. I could check myself, but I thought it would be a lot easier if I asked on the forum instead of ripping up my car's seats. Would there be enough room for me to build a compartment beneath the rear seats of a sedan while still leaving the seats functional?

There is precisely nope amount of space below the rear seats in a sedan.

the cushion mounts to the floor in 99% of newer cars. You might be able to fabricate something small under the front seats.. but you used the term "bass" and i don't think there is room there for a box and big speaker.