Building a stereo room and ran into some problems, help!

I am in the process of building a dedicated sound room and have a couple of situations that have arisen that I cant find a suitable solution to (within threads of through google searches) so I am seeking advice here... background details:
1. Of course I want absolutely 0 sound transfer but I realize that isn’t possible as I haven’t won powerball as of this typing.. So, my goal is to let as little sound out of the room as possible (particularly bass) so as not to bother my wife and kids (that are either one floor above during waking hours or two floors above late night) or the neighbors whose walls are about 20-25 feet away... on a tight budget of course... Obviously I also want qualty sound inside but first things first...

2. The room is in the basement and I went with the "room-within-a-room" motif as the walls are about 3-6 inches from the actual walls, the ceiling is about 18 inches or so below the subfloor above. There is a crawl space below the basement floor so the floor is plywood, not concrete. The room is 11x15 with a 7 foot ceiling (low, but there’s a lot of duct work and piping so it was easier this way..)

3. Sound proofing/isolation: I floated the framing on top of some styrofoam I saw while buying the lumber.. From what I have read styrofoam isn’t the best sound proofing material but having something between the 2x4s and the actual floor sounded logical so I went for it in an effort to keep the crawl space from acting like a giant drum... At worst, I took a chance and blew 15 bucks... There are concrete walls surrounding about 1/2 the room and they are insulated, the rest of the interior area is pretty much open (walkout basement so the front 1/2 is underground sloping down so the back 1/2 is above ground..). There will be insulation between the studs (R13 I believe) and two layers of higher R rating (attic level stuff if memory serves...) in a crossing pattern between the "ceiling" of the room and the subfloor of the floor above. The walls will be 2x drywall with green glue in between the layers with regular drywall on the backside (outside of the room facing the rest of the basement.) Obviously will be sealing the gaps between the sheets of drywall, between the drywall and floor, around outlets, etc... Two cases of green glue have already been purchased...

3. On the table... as with most construction budgets, what you think it will cost and what it actually costs are two completely different things... So just like everyone else, money exists but supplies are diminishing.... I’m looking for effective and as affordable as possible...

The questions:
1. I am considering using the aforementioned styrofoam as a buffer between the studs and drywall.. adding the styrofoam means three layers of "wall" (styrofoam, drywall, green glue, drywall) on the room side of the studs. Thoughts?

2. I don’t plan on finishing the drywall so am curious about how to "finish" the walls and have the makings of a good sound space and also contain sound as much as possible...this is a dedicated room so functionality is the important part... My original intent was to put industrial carpet on the walls and call it good (then add panels as necessary)... I am also considering curtains or large panels that are similar to moving blankets but made specifically for the purpose of absorbing sound... The curtains I am seeing are marketed as black out curtains but the sound isolation benefits are mentioned.. and it’s relatively cheap... I doubt their sound absorption capabilities are "all that" but it is an option... Thoughts or other recommendations?

3. The ceiling... In theory I was/am going to do the 2 layers of drywall and green glue here as well... Ran into logistics as that gets REALLY heavy really fast... So, out went the 2x4s and in came the 2x6s... So now that I have the capability; considering I already have (from high to low) subfloor above, about six inches of open air between the joists, the two thick layers of insulation, and at least 1 layer of drywall.. is the double drywall and green glue necessary?
3a. All of the web sites have begun to blur together but I believe I saw information that stated 2x6s can hold the weight of the two layers of drywall

4. I need to get air in and out of the room, without negating all the aforementioned efforts.... I am blocking off the air vent (physically stuffing the vent with a blanket and not connecting it to the room at all as it is above the ceiling) that would go to the room in an effort to not funnel sound directly to the rest of the house.... So far, I have come up with something along the lines of flexible tubing (dryer vents?) with baffling similar to a muffler inside to simply circulate the air from the basement in and the room air out... this isn’t even an educated guess as I have no background knowledge whatsoever... obviously any thoughts on this would be greatly appreciated as I have found no information anywhere on this issue...

5. The drywall itself... Pretty much everything I have read has stated that 5/8 drywall is far superior to 1/2 inch and one would be a fool not to use it... However, the research presented on the green glue website pretty much contradicts this as the thickness of the drywall had no impact in the final rating (I believe the acronym is SRA). Thoughts?

Any thoughts on on these ideas would be greatly appreciated!!! Also open to suggestions as well but at this point cost is becoming more and more of a factor as I am pretty much already 2x the intended budget so please keep that in mind...

staggered 2x4 walls, not 2x6

use this too:

carpeted walls might be too dead - QRD diffusors are good if not too ugly

buy & read: Master Handbook of Acoustics before going any further

also start doing searches on concert hall designs & recording studio DIYer sites
Did you set up the system in the room before any work was done, play it at desired volume, then go upstairs and outside and evaluate what you heard?

A closed room traps more sound than you think. 
If I’m reading #4 correctly, stuffing any kind of blanket or such into the inside of an air vent as a longterm solution would be a big fat no-no. There will be far too much moisture buildup inside the vent system during normal use and it won’t be long before you can have a serious mold problem on your hands that will require professional remediation that would likely not be cheap.

The best ducting from a noise transmission pov, that is, noise transmission along the length of the duct itself, is the foil kind. They are cheap and quiet, a bit delicate maybe, but if anything happens to it, it can be replaced easily enough...much quieter than the sheet metal, boxed ducting which would require all kinds of noise insulation on the outside of the ducts and they still might not be as quiet as the foil type. But, that only concerns noise transmission along the duct material itself, not along the airway inside it. For that, I’m not really aware of a workable solution unless you’re able to reroute your ducting to a degree and can exit your room air to another area of the house least bothered by the noise, either straight to the HVAC return, or, if there is sufficient return airflow from it, to another room.
Go to Home Depot, and get ROXUL, insulation , to install between 
the studs, great product, and not too expensive, just finished my room, about six month ago, and is a garage convert, dead quiet,
my wife don't even know when lm in the room playing music,
have a concrete floor, that helps, but very happy with my decision,
to use roxul instead of regular insulation,also used 5/8 Sheetrock boards,
good luck:
the walls are 2x4 and are already built so that part is what it is.  The 2x6s came in to play as joists for the ceiling of the room to make sure they are strong enough to support whatever ceiling solution I end up using..

The carpet I am looking at is that superthin industial carpet that you see in businesses and such with minimal pile (maybe 1/8 inch thick overall.)    The exact one I am considering is 50cents/square foot at Lowes so that should speak towards its overall thickness/durability as carpet...  Do you still think that might make it too dead?

I've looked at recording studio solutions but so far the general idea I got from most of that is since one is building a studio they must be pretty serious so spending a few grand on the walls is on the table...  I'm trying to take this seriously but not that seriously....  Admittedly I have avoided concert hall stuff as I didn't think it would apply enough...  Will continue to investigate...

As for the book, I just found some recommendations toward that end yesterday (but noooo, couldnt have found that within my past three months of snooping around the innerwebs.... 😡) unfortunately time is of the essence...  

There was no room to begin with as the basement is unfinished.  I hope you are right when you say the room will trap more sound than I think but this is pretty much a one-shot deal (not absolute but you get the gist) so want to be as effective as possible the first go around... My goal is to be able to listen to the music as loud as I want (just shy of making myself go deaf) whenever I want without a complaint from my wife or neighbors..  I could very well have a nervous breakdown if I finish this project and the neighbors hear anything, bass included..  You wouldn't believe the number of hours I have spent trying to educate myself about sound isolation the past three months.. I knew next to nothing when I started this project...  not that I know anything now but my eyes dont glaze over like they used to when reading this stuff..   I would be more open to "playing" around with different ideas but changing things around once built is pretty cost prohibitive 

good point on the blanket to plug the existing duct..  you wouldn't believe the occupation of the person that suggested it but based on your comment that is definitely out!  Thanks for the save!!!  

As for the foil for the airflow, that's exactly what I was thinking so it seems I am on the right track..  The basement is cool year round so at this point I am not worried about getting a/c in (although we did frame an opening for one for future use if needed.. ounce of prevention, ton of cure!) and I think between the insulation and the heat from the electronics it will be warm enough so all I am worried about is getting fresh air in and circulating it through...  At this point, my intention is to have an opening near the front of the room to draw "fresh" air from the basement in and a small fan and opening at the back of the room to suck the air out and blow it into the basement...  Lot of comments I have read mention that the slightest air leaks (even from unsealed outlets) negate all the other sound proofing efforts so I am wanting to be careful here...  At this point I am looking at building some sort of an insulated box around the openings to mitigate sound escape but haven't come up with a solid plan as yet..

thanks for your comments and keep 'em coming!
looked into roxul but bought regular insulation... cant remember exactly why but there was a reason (I bought the insulation a while ago to help spread out the cost of the project...)  At any rate, I already have rolls upon rolls of insulation sitting in the corner waiting to be used...  Hopefully I can match your sonic bliss with what I have.. thanks for the recommendation! 

As for the 5/8 drywall, like I said in my op, general consensus is definitely use it but the green glue research made me question the efficacy... not to mention the weight when hanging from the ceiling...
just reread your post and noticed your recommendation for soundbreak.. will look into it.. I will say Im not a fan of websites that make you give information in order to access basic information such as test results (to get STC rating) and price....
Mass loaded vinyl is a very sound proofing material, but: it is expensive and it isn't that easy to handle. You don't need two layers of drywall, or for that matter any green glue to make it work. Think of it as lead sheeting in the form of thin vinyl.
Not sure what to do about the ceiling, particularly because that's where you really need to prevent "sound transfer" between floors, according to your original post. 
I've done a little soundproofing to isolate my air compressor for my tone arm from the listening room- it one case, it meant soundproofing a large walk in closet, which was just time consuming, and I wasn't worried about the "above" because it was an outside roof; the other was the construction of a silencer box for the same compressor--I moved--in a customer enclosure I had built. I used a variety of materials for sound proofing, including the aforementioned mass loaded vinyl. It does need at least a mild absorber layer over it, since it is reflective. 
Have you considered using your main system on weekends and headphones at night? BTW, how loud do you play your speakers? Is your lower-level listening room below your living room? Unless you go nuts with the volume control, normal listening shouldn't be a huge problem. Finally, Be sure to spike your speakers/subwoofer for vibration control. 

I helped my brother build his recording studio and some of the things we incorporated are as follows:

It was a room inside a room.  The outside wall was insulated with Corning 703 insulation.  There was an air gap between the outside studs and inside wall.  The inside wall insulated with 703.

Everything had double sheetrock with all air gaps filled with acoustic calk including the framing where it met the floor and ceiling and all walls.

The ceiling was double sheet rock.  It's very important to "float" the ceiling using channel strips designed for this purpose.  It you attach directly into the rafters or joists the sound will directly transmit to whatever is above regardless of the number of sheetrock layers used.  This is critical.

All venting was insulated.  We built collector boxes in the venting runs which were nothing more that a square box lined with 703 insulation.

Yeah, that MLV is out of my league overall but thanks for the input

have a headphone set up I actually really like but this room has long been a dream of mine so am chugging forward... as for the spikes, yup!
As for listening levels... I do like it loud but that is a relative term... when all is said and done with this room it is my inderstanding that once you addrss sound quality within the space louder volumes aren't necessary ...  Regardless, measures will be taken to make sure no hearing damage occurs....  
placement of the room was actually decided based on the facors you mentioned...  it is as far away from the family room as possible and as i mentioned, two floors below the bedrooms with the kids rooms being the furthest away..

room within a room - check!
double sheetrock on the ceiling - care to elaborate on the joists? As I stated, I now have 2x6s for the joists but thats all I have room for and one of my original questions realted to them being strong enough to hang two layers of drywall from
vent boxes - sounds like I am on the right track then

Ok, so a reucrring theme I have seen (through continued research and suggestions) is channel strips.. any recommendations on a DIY method instead of buying commercially available?
Just to clarify.. here is what has already been done/committed to:
2x4 studs, typical application
"room within a room" design..  no walls are touching structural walls and the ceiling is not connected to the subfloor above
styrofoam between the bottom of the studs and floor
johns manville r13 for use between the studs
johns manville r30(?) for use in/above the ceiling of room, 2 layers
2x6 joists on the ceiling 
green glue (2 cases worth) and double drywall on the walls.. already purchased and shipped so committed to this
hopefully double drywall on the ceiling as well but the jury is still out on that
solid core door with yet to be determined sealing
there are some rubber insulated hangers or spacers for drywall that may be useful - forgot the name of them tho, but try a search

la10slgr, the channel material attaches to the ceiling joists and the sheet rock attaches to the channel.  This in essence "floats" the ceiling.  If you search the DIY studio sites it's discussed.  It's also important to stagger your second layer of sheet rock and seal the joints on the first layer.  Doing it right is very labor intensive and most contractors don't get it so whatever you can do will be better in the long run. 
Re: floating the walls away from the studs and ceiling from the joists/2x6s...

Sooooo...  spent the morning looking up isolation channels and by the time I outfit the room (11x15x7) that gets to be pretty spendy

plan b: looked into lining all of the studs with neoprene or rubber stripping...  got to be pretty spends as well... as much as, if not more than the isolation channels...

Plan c:  so at this point I am looking into seeing what they have at lowes, be it styrofoam or other material, that comes in 4x8 sheets that can be cut down in to strips


la10slgr, If your room is an actual room inside a room you wouldn’t need any channels on the walls. If you can leave an air gap between the existing wall and the newly framed inner room, that would be ideal. The actual build up from the outside wall is as follows: rock wool bats, Corning 703 panels, air gap, inside wall with rock wool bats and two layers of 5/8 sheet rock. The ceiling is the only place you would need the channels. There are YouTube videos on resilient channel. You can see the studio we built below.

Sound proofing was the primary design criteria for my listening room. It was designed by ASC using their iso-wall approach.

I think reviewing the design principles here could be helpful. However I should note that even with this specific design and a host of other acoustic and soundproofing features the room does still transmit low bass (albeit very severely diminished) - there's only so much you can do while still being in the same building

ps no discussion of doors yet? This could be one of your main issues for sound leakage. Proper sound proof doors are expensive. This ASC kit is an option for an existing door but is a bear to install properly
will watch tonight, thanks!

will look into that as well... as for doors, mentioned that briefly... solid core door with sealant of some sort and hope it works as $2k for a door isn't in the plans 
Thanks for the contributions... kinda had a day of spinning the wheels in the mud trying to figure out some logistics....  it appears acoustic sealant/caulk is going to be the answer for "isolating" the drywall from the studs...  at this point can't afford other options as covering 40 some studs adds up...  lowes had acoustic something or the other on clearance for $6.50 for a 30oz tube so I grabbed what they had
speaking of mud...

a surface finish with drywall mud or plaster that is rough will be fine - just tell the guy "rough finish"

2 or more coats of primer, then the top coat of paint

you will add absorbers and diffusors later - the former can be manf'd so they look like art prints (of course, they want you to pay for that...)
BTW, it is labor intensive and the panels are heavy but it is not rocket science - you can DIY

plastering is an art (or artisan craft) so hire a good guy after you tape it all up

we should discuss flooring at some point...
those rooms are amazing!  Well done!!!  Wanna come out to Colorado for a "vacation???!!!"

that walldamp is exactly what I am envisioning... now if only they were having a 75% off sale...  i do get that you are only pointing out the design principles and that is exactly what I am trying to accomplish... I'm gonna keep searching but as I mentioned, it looks like the acoustic caulk I got today is going to be what I use...

i mentioned i am planning on using very thin industrial carpet to cover the walls (some dampening but not too much is the idea...) and so far no one has poo-pood that idea...  and you are right, sound correction will be addressed in the future

as for flooring, the current plan is thick or double padding and carpet...  within this, the speakers will be on spikes at minimum but more likely placed on something (i saw some "speaker isolators" yesterday and the concept made sense) to allow the soeakers to make as little/no contact with the floor

Alright, some background knowledge might be helpful here... soap opera coming up

in rereading the posts (and rereading, and rereading some more) it does kinda look like I am being stubborn and not wanting to utilize the resources that have been suggested...  believe me, I would love to implement these awesome suggestions/recommendations but I got some bad advice prior to beginning the project and it set me back a few steps...  

the advice came from a home theater installer I know personally and when this project was in it's infancy he was willing to help and was confident building the room would be about $1000... maybe $1200... $1500 max.. yeah.... so based on this, that is what i planned on and budgeted... you can quit laughing any time now....  not to mention different people have different definitions of "willing to help" but thats for a different day..  needless to say, he's out of the picture..

so now here I am getting indoctrinated in acoustical engineering and realizing that the original budget is absolutely laughable, yet still trying to not go completely overboard, yet still do the room as properly as possible...  Not to mention eventually realizing things I didn't even think to consider beforehand and dealing with them as they pop up...  dilly of a pickle it is!  This is about the point where y'all came in...

So know I have tremendous gratitude for all of the suggestions but at the end of the day, an additional $800 here and another $1000 there just isn't feasible... (keeping in mind I Started with the impression the entire room could be built for $1500 or less...)

Now don't get me wrong, I didn't come in to this totally oblivious and I do expect this to cost some money, which I am willing to spend, but like I said, I have to draw the line somewhere.. hopefully this sheds some light as to why I am always looking for the DIY/inexpensive as possible options...

Again, deepest of gratitude for your help...  Obviously I continue to look forward to any assistance y'all are willing to provide

whew!  I feel like i should go get a 6 pack and watch arm wrestling for a while in an attempt to get some points back on my man card!!!
I'll poo-poo the thin carpet right now then - it will not provide dampening at all; it will diffract a tiny amount at a high freq. but not much.

IIRC, 3/4 inch is the wavelength for 20 kHz - so forget the thin carpet
put points on your man card by tearing the rear suspension off an old Porsche with a big big crowbar without a lift (advanced age & spinal issues add pts.); then put a newer one back on
after posting about the carpet I went back and saw you did poo poo it earlier but it was too late to edit... duly noted....

i dont happen to have any old porshes lying about, or any other spare autos for that matter, so I may just have to go find that arm wrestling... sounds like you put some points in the bank utilizing this method.. ouch!
Just for reference USG sheetrock brand acoustical sealant is really good.  Also if you go down the sealed solid core door route, Zero International has a bunch of threshold hardware.
thanks for the leads!  I already have a door (new for $20! Thanks Craigslist!!!) but will look in to the threshold stuff.. will look into the seals as well
Nothing wrong with DIY. When I had to deal w/ sound proofing issues, a lot of the bargain stuff really didn't do much attenuation. There is a lot of confusion between acoustic treatment and soundproofing. Also, some of the stuff for sound proofing is just expensive. But then, so is labor, and that's something you can do yourself. I wonder if there are any threads on DIY Audio on soundproofing. Never looked. (They have some pretty intense threads on other stuff). 
Good luck with your project- sounds like you are going in the right direction.