Building a Home Studio Ver 2.0

[BigHighLonesome]

Hello All,

As some of you are aware I have recently built a house and I'm planning on putting a home studio in part of
my basement. Well the plans have taken a drastic change and things have got a bit smaller (12*16). I will be moving in on the 26th, and I have have my PDI friday, in which I finally get a chance to take proper pictures
of my basement. I couldn't get out there this week at all, and I know a couple of you are waiting to see these. I apologize. I have made a new post to reflect the new design and direction.

With that being said, I have had to completely re do my design from scratch.
This is mainly due to some last minute unforseen expenses, in which I decided to upgrade some other portions of my house.
I upgraded to an insulated garage door and put slate countertops in the bathrooms. I just couldnt build my original design without making sacrafices so I have decided to build a smaller "one room" design properly.

I have used some floorplan software on my latest design (attached) and it is to scale. I have clearly labeled everything I could. I will take pictures
of the ceiling, but I dont (shouldn't) have anything major running through it except for one register duct. Anyhow if someone could shed some light on any mistakes I might be making or can comment
on how well the sound will be contained that would be greatly appreciated. I am shooting for only 15-25dbs of leakage to my second floor (there will be one floor between the studio and sleeeping level).

The main 1st floor above the studio is Maple and will have hardly any traffic during recording. Overall this house has been consructed above code and is SOLID.

I could have easily built another 700sq/ft into the house design and afforded it , but I built slightly smaller so I could build stronger and use better materials. I can basically jump up and down in my living room
and hear (not feel) a very, very tiny "thud" in my Bedroom, and thats with NOTHING on as far as TV's ect.



Details:

Walls/Ceiling/Floor
---------------------

South/West/North

These walls will be framed by licensed framers/me after the 26th.
- 2*6 Plates (2*4 staggered studs)
- Single (8*4*1/2) sheets of Sheetrock on each side of the wall with 6" batting of Roxul sound and fire insulation (Rockwool).
The SheetRock that faces the inside of the studio will be mounted on resilliant channel.

All joints sealed with acoustic sealant.


East

This is a perimiter outside wall that has been pre framed and drywalled/taped. I am planning on unscrewing the drywall and reworking this section of the basement.

- 2*4 Framing (original framing being kept)
- Single (should I go double thick?) 4*8*1/2" Sheetrock with with 6" batting of Roxul sound and fire insulation (Rockwool) retereofitted to get into the 4" space.
The SheetRock will be mounted on resilliant channel.

All joints sealed with acoustic sealant.



The rest of the stuff on the walls in the diagram are owens corning 703 ridgid fibreglass.

The rolling wall baffles will be 4*4 sections:

The cutaway would look like:

Ridgid fibreglass - Sheetrock - 2*4 frame/Roxul insulation - Sheetrock - ridgid fibreglass on heavy rubber/locking casters. The whole baffle being wrapped in "gold" nylon.

Question: Is this a three leif design? Is this over kill?




Ceiling
---------------
Double thick 4*8*1/2" Sheetrock on resilliant channel with roxul batting stuffed into the ceiling joists and insulation wrap/roxul
heavily around the one small register duct going through the ceiling.

Acoustic sealant in all joints.

Floor
-----------------

North West corner will be floated on 2*4's for drums and amps and anything else thats going to making a lot of noise.

The rest of the floor will be laminate over vapor barrier/small insulation (asphalt paper?).



Questions:

- Need a good link on how to install my resilliant channel ,and any advice would be appreciated.
- Need a good link/advice on building the floating floor section. Also, is it worth it to only float a portion of the floor? Will it increase sound deadening of the drums? In this case thats my goal of this floating floor.

Also, how does this stand up for sound proofing. Is my 15 - 25 db goal (On the second floor) a reality ?
BTW 3/4 of the basement walls are all freestanding and do not join up against other rooms/stairs/neighbors/garage ect ect. The 1 East wall is an outside wall so the layering would be :

Sheetrock - Resilliant - 2*4 filled with Roxul -- Cement foundatation, entire wall submeged underground except the top ft.


Hope you can help.

 

[frederic]

my basement. Well the plans have taken a drastic change and things have got a bit smaller (12*16). I will be moving in on the

As long as you're not making major changes during construction of your studio, its AOK.

This is mainly due to some last minute unforseen expenses, in which I decided to upgrade some other portions of my house.
I upgraded to an insulated garage door and put slate countertops in the bathrooms. I just couldnt build my original design without making sacrafices so I have decided to build a smaller "one room" design properly.

Just an irrelevent comment... I recall your original diagram having space for two rooms, so one thing you might consider if the space is still available, is to build out the larger room as you've designed just now, or at least similar, then down the road as funds arrive you can allocate some towards building out the other room, thus ultimately giving you the two-room studio. When done, move your console and related equipment into the other room. Just a thought, if that helps you plan at all.

- Single (should I go double thick?) 4*8*1/2" Sheetrock with with 6" batting of Roxul sound and fire insulation (Rockwool) retereofitted to get into the 4" space.

I would, the cost is not extreme and you can acquire additional isolation. I did that here in my little home studio and I do believe it made a difference. I used 1/2" for the first layer, and 1/4" for the second layer, based on recommendations I had received from others.

Question: Is this a three leif design? Is this over kill?

This is more Rick's area (and others) than mine. Let me know when you get to the wiring

The rest of the floor will be laminate over vapor barrier/small insulation (asphalt paper?).

If you're going to go laminate, I'd highly recommend Armstrong's swiftlock set of products. Everything from dark to light, oak to beech, even simulated stone. Many of the choices are pretty, its reasonably easy to lay down by yourself, and you don't need to glue them together. The pergo system tends to pull apart a bit as it ages, leaving miniscule gaps that can collect water, coffee, dust, cat hair, etc. Not that you're going to have coffee covered cats in your studio, but you know what I'm saying. The swiftlock system can be bought at Lowes and other home centers, and is reasonably priced. About 5% more than pergo - hardly a painful increase. Also, the surface is slightly textured which gives a nice wood-like look as not only is the impregnated grain pattern visible, but also the textured surface. From what I can tell, it doesn't expand and contract as much as the pergo with temperature and humidity. Be careful cutting it however, it dusts up with a microscopic dust much smaller than sawdust. Its very easy to get into your mouth, nose, ears and eyes. When I was helping my friend install it on the first floor of his house, I wore goggles, a simple paper mask, and put a cotton ball in each ear, and still got some of the dust behind the mask. But its a nice product to work with, and comes with a 20 year wear warranty. Not bad, huh?

- Need a good link/advice on building the floating floor section. Also, is it worth it to only float a portion of the floor? Will it increase sound deadening of the drums? In this case thats my goal of this floating floor.

Making a hollow platform won't deaden, but I presume you know that. You'll have to pack insulating materials (like rigid fiberglass, rockwool, etc) into the joists below the raised floor. You'll have to be extra careful to make this structure resonant free, as it is hollow.

Also, how does this stand up for sound proofing. Is my 15 - 25 db goal (On the second floor) a reality ?

I don't see why not. My studio is essentially a garage loft, with a hallway/bathroom passage to the main part of the house. I've mixed in here at quite high decibels, and my wife in her "office" on the other side of the hallway/bathroom, can barely hear it. My walls are 2x4 studded walls where I used deck screws instead of nails, a layer of plywood, then two layers of sheet rock, with double batts of home insulation installed. Certainly not ideal studio construction, but I do have decent sound isolation. If I "followed the rules" I probably would have achieved better results. I've been told the plywood is unnecessary, however I find it convienent as anywhere I need to mount something (wallmount TV/VCR thing), wall mount monitors, etc, I can just use deck screws instead of trying to find a stud behind two layers of sheet rock. The plywood is glued to the joists, and each deck screw was dipped in silicone before being zapped in. I did the same with the sheet rock screws too - they only reach the plywood, not the joists behind the plywood. Again, not ideal construction, but I am happy with the results.

There are some points in here where I do have sound traveling out of the room, some points I've fixed some I have not. The garage ceiling is plaster swadged over that wire mesh as built in 1941, so since I didn't tear the floor out up here, nor want to tear down the plaster down there, I rented an insulation blowing machine, and blew insulation into the floor. More consistant temperature in the room (the garage isn't heated) and in the garage I can only hear the subwoofer thumping on the floor. Noticably, but with the garage doors shut you can't hear my studio outside, through the floor.

I retained the three 1941 windows, which was a poor choice on my part. Sound does travel right through, though I've installed heavy drapes as a temporary solution but that by itself doesn't absorb all that much. I'm going to have to make rigid fiberglass panels and put them over the three windows, just have been distracted by baby stuff (we're expecting on the 28th) so this has taken a back burner. Something about making dust Soldering I'm allowed.

The other place I lose isolation is the shower stall on the other side of the one wall of my loft studio. Because of the plumbing that's right there, I had to leave the wall open for access, so I've attached a slotted door there temporarily until I figure out how to frame it out and seal it better. Bass travels right through the fiberglass stall into the bathroom next door. Doesn't annoy me, but walking through the bathroom you can hear the stall going thud.. thud.. thud.. in step with the subwoofer. Not too relevent to your issues, but I'm passing that long to indicate why my studio is not perfect.

 

[knightfly]

Only major change I'd recommend - if you're going to use RC, I wouldn't waste the materials to do staggered studs on the one wall - you'll get better results by making the frame stiffer. I'd recommend all 2x6 framing, RC on the inside, and put double layers of wallboard on both sides.

If ALL your inner surfaces end up on RC, this will go a long ways toward killing flanking noise to the rest of the house;

For the drum riser, don't go cheap on the top - higher mass (with the snug insulation fill Frederic mentioned) will lower the resonant freq and keep it damped. Stiffer is better, so if you can 16" centers on framing beats 24", and 12" beats them both... Steve

 

[BigHighLonesome]

Thanks for the advice Frederic,

Just an irrelevent comment... I recall your original diagram having space for two rooms, so one thing you might consider if the space is still available, is to build out the larger room as you've designed just now, or at least similar, then down the road as funds arrive you can allocate some towards building out the other room, thus ultimately giving you the two-room studio. When done, move your console and related equipment into the other room. Just a thought, if that helps you plan at all.

Yes that is the plan. I am basically building the live room now, and the control room later on, within the next year.

I will take your advice and go double thick with the drywall on the east wall. at 11.97 a piece for sheet rock, it will only cost and extra 50 bucks (47.88 to be exact). I just didnt know if it was worth it because the other side of this wall is concrete/oustide world.

I am also planning on stuffing the floated floor REAL good. I just cant really find clear, illustrated pictures as to how I can go about doing this. I have found some pics but they are prett sparse. Maybe I need to go to Chapters and do some research here... for free. Either way when I construct this I will be sure to have the digi beside me and take a lot of shots for future postsers

Same with the resilliant channel. I may just have to get instructions from the home builders and vendors but I really am looking for some clear precise steps on how to install and what to avoid. I dont know a lot about resilliant channel and how to install it.

Over all I am just exited to get hammering away on this. The planning is coming along well.

Congrats on the baby Frederic. Hopefully it wont take you away from the board too much

 

[frederic]

You're welcome.

I wasn't sure if you were going to still do the two room thing, or just bail and do a one room thing. That's why I made my comments on such. No such thing as too much space. I have a one room studio, and while I've maximized every square inch, somehow I do need a little more. I think the bathroom next door is about to become a machine room

I will take your advice and go double thick with the drywall on the east wall. at 11.97 a piece for sheet rock, it will only cost and extra 50 bucks (47.88 to be exact). I just didnt know if it was worth it because the other side of this wall is concrete/oustide world.

My take on this is yes... because sound goes through the sheetrock (two layers), hits the concrete wall, then comes back through the sheet rock (two layers). In the simplest of ways of looking at it, you have four layers for the sound to zing through. Add in the insulation you talked about, and you've increased the friction the audio waves will experience. Which is how absorbtion works - friction through 'stuff'.

I am also planning on stuffing the floated floor REAL good. I just cant really find clear, illustrated pictures as to how I can go about doing this. I have found some pics but they are prett sparse. Maybe I need to go to Chapters and do some research here... for free. Either way when I construct this I will be sure to have the digi beside me and take a lot of shots for future postsers

While not exactly the same thing, my vocal booth is partially over a stair well that exists to the outside, and the garage. I built a hinged platform over the stairwell, so I can still use the stairwell assuming the vocal booth isn't occupied by people or crap.

Essentially its a 2x6 frame, plywood glued and screwed on the bottom, as well as on the top, with hardwood on top of the top layer of plywood. Chaulked all the screws before zipping them in. Inside, is an awful lot of fiberglass insulation. I couldn't find 703 easily at the time so I just double stuffed it. Does it work? yes. Is it perfect? no. But with all the adhesive and screwing I've done to that section of floor (flip floor!), it doesn't flex AT ALL when you lift the side you can reach. Which means its one solid structure. I think that's what you need to do - one massive solid structure. You could put the plywood (or MDF) on the bottom, but you probably don't need something that heavy if its going to rest on the basement floor. You probably need something to make sure the fiberglass batts don't touch the concrete, and get wet should your basement flood, get damp, etc.

Congrats on the baby Frederic. Hopefully it wont take you away from the board too much

Thanks. I'm sure it will... as the preperations have taken up so much time as it is... I still have a ton of soldering to do, some more kick moulding to install, and a huge-ass twin-turbo engine to finish up to toss in my cranky truck.

And this past monday, just because I like to abuse myself with more projects than I can handle, I started machining components to make pneumatic actuators.

oy.

 

[mshilarious]

My only comment is do you really need two PA speakers in a 12' x 16' room? How about a floor monitor for the drummer instead? You've drawn the space pretty tight, so I've just trying to save floorspace here, plus reduce feedback hassles. Or you could even fly the PA speakers above your mix position and drum riser.

 

[BigHighLonesome]

Only major change I'd recommend - if you're going to use RC, I wouldn't waste
the materials to do staggered studs on the one wall - you'll get better results
by making the frame stiffer. I'd recommend all 2x6 framing, RC on the inside, and
put double layers of wallboard on both sides.

This is a go. I was originally planning on 2x6, and this strengthens my decision.
When you say "wallboard" do you mean 4*8*1/2 SheetRock. That may be a bit much.

To do this I would need :

32 panels for the 16ft walls)+24 panels for 12ft walls +24(ceiling) = 80 sheets of drywall .
You also need about 30 screws and 24" of tape per panel + compound and sealant. I also have budgeted for 5-7% waste which has
been the norm throught my house with Sheetrock, brick, stone, and flooring.

80 * 11.97ea (sheetrock price) = 957.60$
And thats not even taking into account RC at 3$ a sq/ft plus fasteners plus screws , tape and mud.
This escalate very quickly in $ and Its just not in the cards. I am looking at about 2000$ here.

If ALL your inner surfaces end up on RC, this will go a long ways toward killing flanking noise
to the rest of the house;

yes, they will be. I just need to find out how to do this properly. at 3 sq/f it isnt going to be cheap, but I am sure the results will be worth it. This is good, as I was hoping RC would really cut the noise flank issue down. So overall you think my goal of 15-25 dbs on the upper level of the house realistic?

Do I need 2 PA speakers in that room? The short of the long here is, NO. But, I wanted to see just
how much room I was working with so I measured my PA speakers 2*2 and plotted them in. When I record they may not even be in the room. Same with the baffles. The musicians whining wll determine where the wedges go and the monitoring set up.

This diagram shows the room at FULL capacity. I know it looks tight, think of how I feel, my plans went from 410 sq/f to 198..

Now to get back to work on researching that floating floor section where the drums will go... thats going to be tough... but after a few more hours of reading I am sure we'll be good. Any posters here install a floating floor or know where I can get step by steps?

So as a rule of thumb to all you studio planners, take the amount of studio space you THINK you can afford, divide that by .5 and that
should give you your REAL square footage ... Man, when it all came down to the number crunching I just fell out of my chair. All the little things dont add up, they pile up!!!

and a huge-ass twin-turbo engine to finish up to toss in my cranky truck.

NICE!!!! How many PSI are you shooting for. How are you going to calibrate your fuel system for this? Anyhow totally off topic but I am a pretty big tuner. I have a hopped up Mazda 3 GT (black 5 door 5 sp, leather) as a project car. I am currently looking at a turbo kit from HiBoost.

 

[frederic]

Poor smore... LMAO.

Why not spread the cost of this room out...

Do one wall, totally correctly, RC and double sheetrock, etc the first month.
Second month do the second wall. Third month do the third wall...

Then when it's all done, you can then take your gear out of there for the mudding/sanding stage so you don't ruin everything, and get the nasty debris over with in one shot.

that's what I did. I used a subset of my equipment and just worked around it. At least when there wasn't massive debris falling down.

Nothing wrong with phases my friend.

 

[DDev]

and while I've maximized every square inch, somehow I do need a little more.

Now that's an understatement

I think Big L, that your layout is cramped (which you already know) but it looks like a good interim solution until you can get your second room funded. For that space I would seriously consider using an electronic piano until you get your mixing stuff out of there as well (my opinion only).

I don't know if anyone has suggested this or not, but for your riser it might be good to fill the gaps with something like rockwool instead of the fiberglass products.

Anyway, just my 2 cents. Can't wait to start seeing construction photos.

Darryl.....

 

[frederic]

Now that's an understatement

heh-heh. actually that is a fib, there is open space under my console table, and one can stand in front of the closet door.

Not for long!

What is cool is once I build the new bathroom in this "widows walk" the hallway/bathroom next to my studio becomes part of the studio - permanently. I'll leave the sink and the toilet, but the shower stall is coming out and I'll frame that out to house 19" rack mount gear. I've already ran 48 TRS pairs, a wordclock coax, and 16 fiber optic pairs (32 strands total) all of which is coiled in the ceiling just above. Just wish I remembered to snake in 50ohm coax for the akai remote control (ethernet)

 

[BigHighLonesome]

Hehehe,

Why not spread the cost of this room out...

Although that is the smartest piece of planning advice I have got to date, it still makes me cry.

I want my jam room, yesterday....

I have the money for this venture as long as it doesnt stray to far from my design posted above. But the double sheetrock on both side PLUS RC is a stretch, especially if I am only looking for 15-25db's on the upper level of the house. The double sheet rock on both walls blows a crater in the budget.

I am actually only planning on living in this house for a few years before building again. I make good money doing this, but sooner or later its time to settle down. In the next house I build I will REALLLY be taking my time and building a studio as I build the house. Most likely the studio will be a free standing building on my property... dreammm.

I know the room is cramped, but I can always remove the PA speakers , push the piano against a wall or roll it out into the rest of the basement (theres over 1000 sq/f of unfinished basement outside this room.

I will also be building a bathroom where the "rough in" is and that will be a vocal booth too. Just an idea but it should work. The bathroom is right across the hall from the door. So basically, if need be, I will have a separated vocal booth across the hall until I can build my control room


PS: The piano is an electric piano (Yamaha CLP 50) and is 5*3, the illustration shows it around 5 * 5

I totally agree, I will be using rockwool batting to stuff the riser and the bottom of the riser will be sealed, and floated.

 

[BigHighLonesome]

I have found this write up on floating floor construction is case anyone is interested. Its a start..

http://www.diynetwork.com/diy/hi_family_room/article/0,2037,DIY_13912_3465241,00.html

 

[frederic]

Although that is the smartest piece of planning advice I have got to date, it still makes me cry.

So cry, get it over with, and start the first wall

I want my jam room, yesterday....

And I want a winning lottery ticket.

Anyway, not trying to break your balls, just wearing my Captain Obvious cape for a while ...

 

[knightfly]

Last year I paid $2.16 per 12' length of RC locally (drywall contractor supply) - what RC are you looking at and what's the cost per stick?

On the double wallboard - yes, that's what I meant. Where are you located that 1/2" drywall costs over $11 per sheet; is that 4x8 feet or 4x12?

If you can't afford that much wallboard, but still want better isolation and less need inside for bass trapping, one way is to double the EXTERIOR wallboard ONLY, then a single 1/2" layer inside - this acts somewhat as a panel bass trap, and can lessen the amount of bass trapping needed to balance the sound in the room.

For a lot more on floors, walls, RC, etc, check here -

http://www.johnlsayers.com/phpBB2/viewtopic.php?t=2125

HTH... Steve

 

[BigHighLonesome]

The resilliant channel is 3.50c for 12'. Something was noted on the tag about it being "furring" or something and then there was 12' sticks for 4.00. I thought this was the price by the foot, not 12 foot lengths. Wow, that free's up some dough.


The price for sheet rock in Ottawa Canada (Nations Capital) is 11.97ea and the dimensions are 4x8x1/2" Cheap? Expensive? Rip?

Sometimes it can dip down to 9 bucks but with reno season getting underway that price will most likely jump to 12.50 within the next 2 months.

Damaged Sheetrock prices:

4x4 4.25
4x2 2.50

Doing the double layer on the outside wall is completely doable, I was planning on the opposite though, double inner wall, single outer wall.

Thanks for the link, I will enjoy the read. I have learned quite a bit the last few weeks about this stuff. Thanks again.

Also, its about 13 bucks for a sheet of 4x8x1/2" ridgid acoutic fibreglass. Something about 75kph? Whats that stand for ?

Frederic, I have figured out a way to make me feel better if I have to do this in stages.... I simply think of my old days when I had 3 of my adjoining walls attached to asinine neighbors.

 

[frederic]

Damaged Sheetrock prices:

4x4 4.25
4x2 2.50

YOu pay for damaged sheet rock? Heck, my lowes puts it outside in a dumpster right out in front.

Usually not nice sized 4x4 pieces, but I got quite a few good pieces that way when I did the bathroom downstars. I lifted out the sheets, cut it on the tailgate of my truck, put the good part in and tossed the ragged crap back in the dumpster.

LMAO

 

[knightfly]

Price for 1/2" 4x8 sheet rock at Home Depot (Oregon store) last week was $6.79 US, 5/8 was $7.89, up from $6.89 a month ago, up from $5.90 2 months before that - sure wish my WAGES came half-ass close to keeping up...

Here's a serious wall document from your side of the fence, also linked from the earlier link I posted; tells how to fasten, how close, etc, along with 350 different BUILT and TESTED wall assemblies -

http://irc.nrc-cnrc.gc.ca/fulltext/ir761/

Once you get the pdf downloaded, it's pretty easy to compare for different designs - if you use the right/left cursor keys, you jump to the same spot in the next/previous page, so you can focus on one place on the page and jump through 350 walls to see what's different... Steve

 

[BigHighLonesome]

Thanks Knightfly.

Yeah, thanks for the link! I have been doing so much reeadin my eyes are bleedin' but wow things are getting very clear. Sound is almost like fire, you have to find any angle you can to stomp it out. Pretty cool stuff. A science.

Building materials are crazy up here too, but are seasonal. I am an experienced house building project manager. I know, the best time to build is through the winter. I usually make sure foundations are poured before the frost, but thats it. As I have mentioned before, if I would have built my house during the reno season I would have forked out an extra six grand for LUMBER (2400sq/ft 2 stry). Speaking of, you guys are really missing out on our softwood... The cold cold climate up here mixed with our summers makes for some unreal lumber. Just ask China

Frederic, I know... its unreal. Most of the damaged selection looked like it had been taken for a swim and backed over by Gravedigger...

YOu pay for damaged sheet rock?

Not me. NEVER. I cant figure that one out yet, and just thought I would throw it out there.

Weak. But what can I do? I am expecting a call from my builder any moment...... I may have the wholesale connection going on for SheetRock. We'll see.

Cant wait. T minus 9 days.

 

[JasonB93117]

Probably Not New Info...

You probably have already seen this stuff, but anyway there's a section on floors at http://www.saecollege.de/reference_material/index.html - the part on floors is found under the "construction" tab on the left and then the "floors" tab on the top. - Jason

 

[Dan Merrill]

BiGHigh,

I've built a similar room myself -mine's about 17x 11. And actually, it's part of a separate building that was built for studio purposes. I have a two room set up the other room is maybe 12x11. the control room has 3 walls and ceilings with RC and one staggered stud- (the wall which separates the two rooms). I can't say for sure which is better but i will say, i like the staggerd wall better for the purpose of hanging stuff. I'm not so afraid of breaking the acoustic seal when i put a drywall screw through the 2 layers of drywall straight into the stud to put up a String Swing guitar holder. I don't / can't do this with the RC walls.

Here are some of my other thoughts for consideration:

1. Although it all fits in CAD, that room is going to be packed! While I do use my control room to track drums, it gets VERY tight in here with drums, a synth and a guitarist (and me) . I can't imagine having a drum riser too, much less the flexibilty I would lose by putting one in. I'm always moving stuff around to form a vocal booth when needed. Maybe your place is for your band and the set up won't change, but I would (and did ) opt for flexibility. I dropped my plan to carve of part of my room for a vocal booth and am glad I did.

2. It's gonna be freaking loud in that room! It scared me the first time i went into my room after it was RC'd and sealed up. All the sound stays right there in the room- and drums will kill you. My point is: you gotta plan on acoustic treatment- which uses space- how high is your ceiling? While planning your soundproofing, I would try to incorporate as much sound treatment into the design as possible. John Sayer's reverse walls come to mind. My control room is now under control with: 8- 2'x4' panel absorbers, 6 cylindrical bass traps, some auralex foam, and perhaps some low end help from the floating floor. You gotta plan for it and i think maybe sacrificing some space to incorporate it into the design, rather than after, is something I might have done differently.

3. do you need a floating drum riser on a cement basement floor, what's the purpose exactly? I don't think there's much acoustic coupling going on with a cement floor. Although, If you have the room height, you might consider putting a full floating hardwood floor just for the bass trapping and acoustic sound qualities of it- and another place to lay cables.

4. Speaking of cables: Got all your wiring in those walls planned out? Audio snakes, wall panels, A/C, lights, also taking into consideration them being terminated in the right places for when control room 2 gets added? Once those walls are closed, they're closed... BTW, I use the furman HDS-6 for headphone distro. I installed cat5 connectors in the walls throughout and it works great . I've got 6 headphone stations throughout (total of 12 users at once) and no cables all over the floor. Nice to be able to do that stuff when building new walls.

The fun's just begining for you!