This thread may be old, but I have not seen any of these suggestions sooo OK, time to apply some old school audio tricks. The way houses are made today is cardboard. so sound proof your garage. ceilings are a pain, but options---if you have the $$ have your walls sound proofed by shooting foam in them,,, but for guy who doesn’t want to do that,,, acoustic foam
Auralex 2" StudioFoam Wedgies 1'x1'x2" Panels (24 pack) | Musician's Friend covers 96sq feet. around 106 bucks. Apply to ceiling and walls. for floor do what I have seen a few guys here do, cover the floor with the interlocking foam pads you can buy at big lots or home depot,,(look at baby resale shops, it may be multi colored but cheaper) and roll a carpet remnant over it or a big piece of walkway rubber. -cheaper still? Carpet padding and carpet. If you want to go a different rt, you can get area rugs and hang them from the walls. wife might like a nice oriental design they also have planin white ones that wont look out of place. Cheapest still, cardboard drink holders. Anything that will disrupt and absorb the sound wave. That is why old school studios like Sound City (probably the last of its kind and is now gone

) had thick pile carpet all over all the walls.