There are different ways to handle sound transfer short of carpeting.........sound is transmitted through floors most often with direct contact of hard surfaces. Example: floor joists contacting sub floor, sub floor contacting hard wood.........sound has a direct transmission path from the attic to the floor below, with the space between the attic sub floor acting as a diaphragm to amplify the sound.

If you haven't laid any sub floor yet in the attic, one simple step is to put a neoprene strip on top of the floor joist, then put down your sub floor. Then if you want to go with hardwood or a manufactured floor system, I would put an isolation pad on top of the sub floor as well and go with a floating system. Actually, some manufactured systems come with a sound isolation layer already attached on the individual planks.

This will minimize most of the sound transfer.........true sound attenuation is a process that to get the best results you need to include them in the original construction (i.e. resilient furring strips used to attach the first floor finish ceiling, sound attenuation blankets in the air space, etc., etc..)

A very good informative response by S Thomas Kutch. Pity we can't stick this info up somwhere on Houzz as a permanent feature.