Read all of this, it goes into a good amount of detail, certainly enough to get started.
Almost nothing will stop bass, because it transmits very well via flanking, bass contains a LOT of energy.
It will travel through beams, through the ground, through a rooftop, it travels through almost anything. Lots and lots of mass (like cement) on all 6 sides 8inches thick with zero gaps or holes is the only way to stop it.
The quietest room in the world is like 60ft underground, with a room made out of 6 feet of solid cement on all 6 sides, and in side that room, is another room made out of cement that floats on springs, and then inside that room, it is coated on all 6 sides with 4 foot wedge absorbers.
It will not be cheap, expect $6-20k to only PARTIALLY
solve the bass problem.
Building an underground theater building in your backyard is the best solution, above ground is the next bass, an adjoining structure is the next best, a structure under your driveway is the next best, and the worst: is a room inside your house made of normal-build construction techniques.
I went with an above-ground backyard structure solution, it has 90db of noise rejection above 200hz @ 1ft, and at a combined distance of 75ft of air and/or dirt with an additional 12" thick wall of soundproofed wood & drywall I get about 40db of bass reduction, if not slightly less.
I had to, when my system was in the basement of my main house I was breaking dishes upstairs, and nobody could hear the living room TV (which was powered with a 600watt 5.1 speaker system).
My system is one of the loudest systems on AVS. With OVER 35,000watts and OVER 22 SI-18inch subwoofer-equivalences of bass, for starters...
A bassheads gotta do what a bassheads gotta do!
So, 8inches of solid cement on all 6 sides (yes including the ceiling) with no physical attachments to the main-house is the MINIMUM to get good bass reduction, depending on exactly how much of a basshead you are.