To soundproof your room you will need to use a combination of materials. The following video link is a brief demonstration on blocking sound: http://acousticsfirst.com/educational-videos-the-barrier-and-the-bell.htm We use a mass loaded vinyl called BlockAid. (http://acousticsfirst.com/blockaid-vinyl-sound-barrier.htm) This can be added to structural composites to increase mass without loosing valuable space and can be used in conjunction with resilient channel, isolation hangers and acoustical sealant. Always line cavities with insulation. This prevents resonant frequencies from ringing in the cavities and increases the STC (Sound Transmission Loss). To keep structural noise from transmitting through the structure, be sure to isolate materials using resilient clips or resilient channels. Sound and noise can be transmitted structurally through any materials that touch without some type of resilient material between them. Once your structure is complete, you can use acoustical treatments within your music room to absorb sound and improve the quality of sound in the room. Even though acoustical panels do not block sound, they will help reduce the overall sound pressure in the room, much like the fiberglass batting that is used with the barrier material in the video. A drywall ceiling may sag if the contractor did not use drywall meant for ceiling applications. Be sure to check with material supplies to confirm that you have the correct material for your application. Here is a link that might be useful: Soundproofing Demonstration

If you do a search, you'll find that there have been several threads on this topic recently. In terms of what it is called, you want to provide sound attenuation. You would never "sound proof" your house. It would be ridiculously expensive (if you could even manage it), and it would be very uncomfortable. I am an audiologist (although I no longer practice), and I find that being in a "real" sound proof room is a very weird feeling. Almost suffocating... So, what you would be looking for is a product that would help to decrease the transmission of sound between rooms. You need to determine what dB level of noise transmission would be acceptable to you and from there you can begin to plan the products and strategies to make it happen. You can work with an acoustical engineer to come up with the correct formulas, but you will need to take into account multiple factors, including but not limited to flooring materials, ceiling heights, room sizes, etc. Most homeowners never go into that level of detail...it certainly does not sound from your posting that you would very much attenuation. One very easy fix is to use carpet upstairs rather than a hardwood...much quieter.

There are many levels of sound transmission reduction designs. One of the simplest and most basic is to insulate all walls, floors and ceilings. This quiets down a home quite a bit. As you mention there are lots of other ways that will achieve better results but are usually more expensive or complicated. Because your recessed housings are IC you can blow insulation or stuff insulation in the cavity around them by sliding the cylinder down to access the space through the hole in the plaster frame. Make sure the ceiling is sealed to the housing by caulking where it meets the drywall if needed. Then buy and install airtight rated trims.

@ bry911 "We have had indoor toilets that spray fecal matter particles in our bathrooms for the past 100 years without any reported epidemics caused by this great imaginary health risk." "Who said anything about a health risk? I said something about the rather ridiculous assertion that if your toilet is separated from your sink by a door handle that you have an increased risk e.coli... -- Curb your arrogance. I did not mention you and I was responding primarily to the comment made by loobab regarding e-coli transmission in a home bathroom environment, however, your response to loobab "You can't really be worried about touching fecal matter on a door handle while not being worried about airborne fecal spores." suggests that airborne fecal spores would impose the same risk. I may be missing something, but in my mind, any concern regarding transmission of e-coli in a home bathroom environment would be a largely "imagined" health risk I cannot think of any other concern other than health that relates to the transmission of the e-coli bacteria. "you along with 99% of the population." I hate to be picky, but nope... First, only about 70% of the population even have toilets. Next, squat toilets are usually separated and since squat toilets outnumber sitting toilets 2 to 1... Most of the world craps in a different room than they brush their teeth in. -- Speaking as a statistical data analyst - A "statistic" (99%) is a characteristic of a sample drawn from a defined population. The "population" references a group of phenomena that have something in common. Since we have been discussing bathrooms with flushing toilets and I had stated "We have had indoor toilets that spray fecal matter particles in our bathrooms for the past 100 years" that would infer that the population that is being referenced is the population of households with flushing toilets.