I redid the ceiling in my basement mancave a little over two years ago. One of the things that I did that was a big improvement for relatively little money was stapling 30 lb roofing tar paper between the joists to the 1st floor flooring.It didn't change the SQ in the listening room by much, but it did drastically cut down on the sound leakage to the rest of the house, which was a big win in the marital harmony department.
The tar paper itself was pretty cheap (less than 1$100 did the whole room) But it was a bit time consuming cutting it and putting it up. If you do decide to do this I would strongly recommend getting either an electric stapler or a small compressor and an air gun because you will need a whole lot of staples and pulling on one of those spring loaded Arrow stale guns will get old in a hurry.
This method gives you tree separate layers of sound dampening (the tar paper, the ceiling itself and the air gap between them) and it really helped me out a lot. I don't know this from experience, but I did read that this works better than stuffing fiberglass insulation between the joists because the physical contact between the insulation and the ceiling and the insulation and the floor above and act as a sound conduit.I'm not sure how much more that insulation will conduct over and above what is getting transmitted through the joists, but that's what I read (Hey - it was on the internet, it
has to be true
) But I can say that the paper and the air gap worked really well for me.