Sound proofing floor

I'm looking into the mass loaded vinyl and a few other options. I'm on the 4th floor of a 4 story building. I'm not playing my music extremely loud ( too me ) My neighbors on either side don't hear my music, I've checked with both. It's just the neighbor below. It's not extremely loud to my neighbor but just enough to be bothersome when trying to sleep.For a temp. solution I've turned it down a little, put a pad under my sub woofer and turned my spikes over so thet're not going through the carpet to the sub floor. I've ordered spike pads so I can turn the spikes back the correct way.

Are they "hearing" the bass or midrange/treble as well? It doesn't make sense that all frequencies are passing through unless the whole floor is hitting a resonance with your music. It's pretty hard to stop the long bass wavelengths. Isolating your floor from the concrete is not practical, but would help immensely. Have you set the volume to where you like it and gone downstairs to hear it for yourself? That might help develop a solution.

sometimes bass and other times music I'm told, not very loud, I turned up music 1 at a time and had her call when she could hear it. It was a little louder than I normally play it, but some songs can play a little louder than others and some the bass pops in. I'm just looking to decrease the sound traveling through the floor a little.

Just ordered the 1lb MLV, we'll see ho it goes.

Time for  headphones 🎧