Originally Posted by creepy coupe
I think I'd sooner go this route rather than Rockwall. It would save you having the floor up and you'd only need to have the bottom of the doors planed.
That would work too.
If you want it done semi properly. Rockwool between the joist. Then neopreme rubber strips laid on the top of the joist with the floor board place on the neopreme.
Sound is one cause but machinery will and it's frequencies will vibrate the joist. All three would work best. But be aware of raising the floor high as doors will then need cuttin to size.