First Post - Basement Studio Finishing Materials and Design

[Museth]

Hello all,

This is my first post here. First off, want to thank the forum for existing and all it's contributors! A ton of useful detailed and useful information shared here has been extremely helpful in the planning and use of materials for my music basement workspace. After about a year and a half in the planning and I'm now I'm less than two weeks away from starting the basement finishing. I've got some specific questions I could use an experts' ear and thoughts on. I will try to be as detailed as possible in giving account to where I'm at at this point, (as well as how and why I got here) and where my 'open ends' still are that I could use some helpful advice on.

Space usage / purpose:
I'm a full-time musician (performer / teacher). The uses of this basement space will be four fold:
1. Recording / Mixing - most of this will be direct or close-microphone recording (vocals, guitar / bass DI, sequenced drums, keys), so it's more important for this space to act like a control room than have the dynamics of a tracking room. Acoustic accuracy, neutrality and a strong, uncolored stereo is really important, especially in the mixing chair.
2. As an environment for teaching. I teach guitar, voice, bass and uke to students young and old. Soundwise for this, I want it to function similar to a control room, so 1 and 2 are very similar, but this is where the aesthetics really come into play. I want it to be a warm welcoming environment that feels like another room of the house and not a 'basement' (what it is now). I also use recording as a teaching tool, so again emphasizing the tracking room mentality.
3. As a backdrop environment for a YouTube channel.This piece doesn't have as much to do with sound as aesthetics but there may be some live room recordings where the acoustics of the room come into play here, especially with dialogue . The channel will include blogs, teaching videos, acoustic / voice (maybe live) covers of songs and full-on arranged covers of songs (ex. heavy metal cover of Britney Spears, country version of something by LMFAO. Outside the box stuff).
4. Occasionally as a band rehearsal space (very infrequent) and even more infrequent (but possible) tracking space for drums.

Existing construction of the room:
(include room diagram)
Dimensions: 24 x 12 x 7. Foundation - poured concrete walls, concrete floor. Stairs at the back of the room.

BasementCadDrawing.png

Ceiling is unfinished, wooden floor joists are 7 1/2 inches deep x 1 1/2 inches wide with 14 inches between. When we moved in, the room was wood paneled and wood-studded behind w no insulation. Ceilings were an older type acoustic tile. Had some water issues when we moved in down here and had those taken care of by one of the state's top waterproofing companies (new drainage system outside, foundation addressed / resealed, drain pipe installed inside, sump pump for ground water. All existing finishing that came with the house down here is getting ripped out.

I'm the kind of guy that wants to do something, once, right and never have to worry about it again when it comes to house remodeling. I also have a mold allergy and wanted to make sure that I cured the existing problem (there was mold growth behind the old wood panels and a continuous musty smell) and then took steps to prevent it from happening again. Had the waterproofing done, but you still have to control the inevitable humidity and water vapor that will come from climate variances and the concrete 'sponges' surrounding me on the walls and floor.
I'm going to be using a Sani-Dry dehumidification system for water vapor / humidity control and air purification. Air quality and smell is also very important for my students and parents and for my own children as well.

SaniDry dehumidifier (for anyone who cares):
http://www.basementsystems.com/basement ... nidry.html

This philosophy of a be-all end-all once and done led me straight though to prioritizing and selecting finishing materials for this basement that are highly moisture resistant, inorganic and durable (because this is the one and only time I want to do this). Mold won't grow on materials that don't hold moisture and it can't feed on. In other words, no wood, drywall or paint if it can be avoided, especially regarding the floor and walls. This eliminated a lot of the more 'conventional' finishing materials that folks typically use in home studio construction and led me into having to do a lot of research, especially on their sound properties. Given my sensitivity to mold, coupled with the fact that basement environments have different 'needs' and the fact that I needed this room to be just as 'cozy' (if not more so) as any other room in the house, figuring out this part of the equation became priority and had to be taken care of first.

OVERALL GOAL
To maximize use, layout and design of the existing basement space using the most durable inorganic finishing materials available to its' fullest potential along the four guidelines:
1. FUNCTION - Basement Specific: again, have to be inorganic (as much as possible) and not support mold growth whatsoever. Durable, and hopefully provide some energy efficiency to the house.
2. FUNCTION - Sound: With the dimensions of the room and inorganic materials prioritized, the finishing layout, construction, design and use of those materials within have to work FOR the sound physics of the specific space as much as possible, prioritizing my four usage goals. (treatment will be added after all the initial finishing work is done).
3. FORM - Aesthetics: I have to LOVE the way the space looks and feels. It's my office, my studio, my place of business (and relaxation at times), and where I will be spending a ton of my time. The aesthetics of the room represent me to my students / parents as well as am to the larger internet video world / YouTube channel. Needs to be comfortable, functional, inviting, universal.
4. FORM & FUNCTION - Future Proof: easily manipulatable. Not closed off, or a pain in the butt to run, for example wire through the wall or ceiling later if needs change. Walls durable enough for 8 year olds accidentally banging guitar cases into them and not dent. Ideally, flexible enough to hang anything anywhere (acoustic treatments, tv's, etc) without having to worry about where studs are.

The way that I look at the goals as a square. All sides need to be balanced, and as equal as possible in my case and as you guys can see, I really need to maximize every inch of this little space and what I do with it's blank canvas.


To where I'm at with this now:

I spent about two years looking at different finishing options (drywall, wood, carpeting, different tile, leaving the bare concrete etc..). I weighed using a company / contractor vs doing it myself. I spent a ton of time on this and other forums which have been helpful beyond words. In the end, I decided to use the Total Basement Finishing System. I'm not much of a DIY guy and can't afford to shut down my teaching biz as I work on things here and there and need it done pretty quickly and efficiently. They roll it out in about a week. The finishing materials they use are almost completely inorganic and help to satisfy a lot of the goals mentioned above simultaneously, and their system has a very comprehensive warranty.

Work is scheduled to begin in about a week 02/22/16 and I'm meeting with the contractor tomorrow (02/12/16) to nail in some of the last minute details and pricing things.

There's a lot of options in their system for finishing products, and my goal is to maximize a combination of their materials to get the best balance for the four goals (again, 1. basement specific, 2. materials used don't hurt the room for the usage goals as they relate to sound and even help where possible, 3. aesthetically pleasing, 4. future proof). The following is a breakdown of what and where materials will be used. Most materials I'm pretty locked in on, and others I'm not sure about. I'll provide the names of these products within their system and be as detailed as I can, as I'm sure it will come in handy when we address the sound questions and concerns. After balancing everything, here's where I'm at as of today.

Walls:
Insulation - I'm using their Basement to Beautiful wall panels. These are 2 1/2" thick EPS graphite-infused (drives R-value up a little) panels that will be mounted directly to the existing concrete which are prefabbed with electrical chases, (vertical chase every 32' and two horizontal chases at 16' & 64') and and 1/2' metal studs engineered to the front of the panel (don't go all way through so there's no thermal break). These are tongue and groove, much like some of the Owens or Dow stuff. Very rigid.
Finishing Panel - Their Everlast wall panel. It is a 1/2 inch cement board mounted to the EPS foam, covered with a washable off-white / beige 'slightly alligator-textured' vinyl finish. Harder than drywall, easy to clean, impossible to dent, anything can be mounted anywhere - rigid enough to mount a flat screen or bookshelf from, regardless of stud placement. Screw holes can be patched with putty.

Basement to Beautiful video link:
https://www.youtube.com/watch?v=B24pDEMQ-lw

Floors:
Carpet Tiles - They call it ThermalDry. Tiles are polypropylene base with polyolefin carpet top. It's a modular, floating interlocking carpet tile floor matting system that creates a airspace between concrete floor and your feet with spacers on the bottom of the tile. The company also has regular tile and wood planking options which I considered and hit later..

Product Link:
http://www.mateflex.com/products/carpetflex

Ceiling:
Unfinished Ceiling Painted with black Dryfall w recessed lighting cans installed and painted to match ceiling.


Question 1:

The ceiling. I've done as much research and read through as much as I could find on forums regarding how to address one of my biggest acoustic issues. the low ceiling. The height from floor to unfinished ceiling is just shy of 7 feet. The living room to the house is right above where the mixing area will be and I have a 4 and 6 year old with heavy feet, so impact noise is a bit of a struggle, but something I can deal with based on how and what I'll be recording.
Taking everything into consideration, I need a solution for the ceiling that ideally balances:
A. Isolation - (impact noise from above and my noise from below at 3AM in the morning w late night mixing session),
B. Absorption - high / mid freq absorption, some bass trapping would be a bonus.
C. Doesn't look horrible
D. Doesn't sacrifice precious ceiling height and close off duct work and wiring.

As far as the impact noise, I plan to eventually add some thick carpet in the living room to soften footfalls but I realize that without adding mass, I can't do much on that end (except maybe training them to walk like little ninjas). Drywall for the ceiling is not an option. Closes off ductwork / electrical and absorbs very little, which is a high priority for my control room-esque environment. Keeping with one of my inorganic materials priorities, I want to try to avoid drywall as a whole. Contractor also does not offer it as an option so I'd have to do that myself.

Regarding TBF (Total Basement Finishing - company I'm using), they offer a drop ceiling option with 2 x 2 foot .55 NRC mineral fiber tiles from USG. From most of the folks in a similar situation on these forums, it seems the recommendation if there is a choice is to skip the drop ceiling entirely in favor of ceiling height. Also read that these tiles are great for office environments, but poor for high-frequency absorption. Aesthetically, I don't like the way the tiled ceilings look and it's even less favorable to me to lower the ceiling 4 inches. On the other hand I've seen mention of ceiling tiles topped w the fluffy or Roxul being a potential bass trapping option. I've run across another ceiling tile system mentioned in the forums (which I could probably install myself) called CeilingMAX that flush mounts the frame under the joists so you would only lose about 1/2 inch of ceiling height instead of 4 inches.

Regarding leaving the ceiling unfinished, I ran across a post from a fella named Craig John on the AVS forum who had a pre-existing drop ceiling and was looking for the best way to treat it. Ethan Winer suggested, " pull out the grid, which will give you more height, and pack the cavities between joists entirely with fluffy fiberglass. Then you can staple fabric to the joist bottoms, and add thin wood trim strips to cover the staples. This will be much more absorbent at high frequencies than any ceiling tile, and all that fiberglass will give a nice amount of bass trapping. It will also cost less than replacing one grid with another, and is probably less work too."

A member of the John Sayers' forum, beautyfish, posted, "With my seven foot ceilings, I would like to make the control room ceiling "disappear" as much as possible, both acoustically and visually" where he mentioned the insulation / cloth idea as well. I've seen this idea echoed by a few others.

Out of all my research, this solution seemed to me to be the most logical, balanced solution to construction / treatment of the ceiling. Mentioned this to my finishing guy with TBF I'll be working with and he said they could just paint the ceiling with black Dryfall. I like the aesthetic of the industrial look and the idea of the ceiling disappearing visually.

So…with the desired sonic goal of the space (control room dynamics -acoustic neutrality, pretty dry), and the 'givens' (aforementioned wall materials, carpet floor tiling,) am I on the right track with the solution of insulating the joists and then stapling fabric to the joists? If so, is it better to use Roxul (and specifically what kind), the pink fluffy, or rigid pink? Is there anything that I am missing? Also, regarding aesthetics, does anyone have a picture of what this looks like as a finished product?


Question 2:

My decision to use TBF's carpet tiles was based on several factors:
A. Again, inorganic. The polypropylene construction and carpet material they use have nothing for mold to feed on. Also if there is ever a plumbing leak, the floor doesn't have to be torn up.
B. Sound. Absorptive w high (and some mids?) frequencies.
C. Aesthetics. I like the color and it blends well with the wall tones. I can walk around barefoot if I wanted to.
D. Future proof. Modular system - you spill coffee and stain it, you can replace the specific tiles if they are beyond washing. If a tile is damaged, you replace that tile.

The company has three other options - wood plank vinyl flooring, vinyl tile (ceramic look), or vinyl subfloor system that carpet can be laid on top of. All options create the air pocket off the floor which provides the thermal break.

Video link to their flooring options:
https://www.youtube.com/watch?v=WO-9XFxaLpw

From what I understand, a reflective floor is favorable in a tracking room, (esp if recording drums), but absorption as a mentality for a control room (esp a smaller one with low ceilings) is favorable. If I do the ceiling with the Roxul and fabric and use the carpet tile from the floors, there would be a good deal of absorption from that. From what I understand, you don't necessarily want any room TOTALLY dead. The wall vinyl coverings are hard, reflective and probably insignificantly diffusive because of their slightly raised varied alligatored texture. Given the materials they offer, am I on the right track with these carpet tiles for what I want to accomplish with the space?


Question 3:

From the basic diagram of the basement, you can see that it's pretty much a 12 x 24 rectangle. Early on with the design, I was considering dividing this space into a control room / tracking room, and getting the dimensions of the control room to closely match one of the ideal room ratios. This idea was also of value from a teaching perspective, as students (especially vocal) become embarrassed when the next lesson shows up because their mistakes can be heard and so on. Control room would function as the lesson room and tracking area as the waiting area. When I investigated the potential sound physics / consequences of the splitting idea however, (standing waves, room nodes, sound pressure), the general wisdom seemed to be, it may look / seem cool in your head, but better to have a big space the LF big waves.

Don't know anything about Brandon Drury, but I came across an article of his titled, 'Top 11 Recording Studio Construction Mistakes.' Regarding splitting the room, he posted, "I never understood why people don’t just take a chainsaw and cut their car in half to make two cars. Two cars is better than one. If you have tried this OR you have taken a perfectly good 10′x20′ room and cut it into two horrible sounding rooms, you know that neither approach works. There is a critical mass when it comes to cubic volume of a room. If you nail it, you avoid all kinds of acoustical problems."

Based my research of this area in relation to the propagation of sound in a small room, this advice seemed sound. The two room idea is cooler and costs more. I sacked it, but construction hasn't begun yet. The question is, based on my goals with the space, is this (one big room instead of two smaller ones) the right starting call pre-treatment to achieve the best acoustic neutrality and least pressure issues?


Question 4:

Doors. The entire basement is a square, divided by a poured concrete support wall that divides the square into two equal rectangles with 12' length - the finished room (the topic) and the unfinished laundry room. There is a bi-fold door that opens to the unfinished side where the washer, dryer, sump pump, dehumidifier, and furnace are. I would describe noise coming from this room at its' loudest point as moderate at most - not horribly loud or annoying at all. TBF uses standard hollow-core doors for their projects unless otherwise specified. There is another standard door at the top of the stairs that opens to the basement.

I am looking for one or two steps above the basic here. Best value for the dollar above standard hollow-core. Believe it or not, the hollow core will give me more than the flim-flam door that's there now. Any suggestions and or links you guys could give in this regard where a few extra bucks will go a much longer distance in terms of sound isolation?


Question 5:

Stairs and cavities above and below. Two potential issues here.

A. The stairs come down at the back of the basement to a 3'1/2" squared floor landing. Right now the area under the stairs is walled off with the old cheap wood paneling with a door that opens to the area under the stairs for storage.

IMG_1290.jpeg

The mixing console is moving to the other side of the basement once it's finished. The plan as of now is to open the space totally up under the stairs into a 'Nevada' shaped area for storage under the stairs in which I could put my various guitar, bass and other cases / things. Storage areas in the basement, even with the unfinished side, are going end up being a premium. I know I will want to bass trap the corner of this area. I was also thinking (hoping) that the different sized guitar cases could double as a bit of diffusion and the finished Nevada cove under the stairs would give me a small amount of bass trapping. Regarding diffusion, another thought I had was maybe I don't want to open it all the way up - just use a taller door than what's there with the new finishing and use the other half of the wall with it's back to the stairs as flat surface for a diffusion panel as it will be the wall in the back of the room. Any thoughts on how to best maximize the potential of this area in all directions (bass trap, storage) would be much appreciated.

B. The stair area. Right now, my mixing desk is temporarily on the stair wall, and I've noticed that the stairwell area acts as as sort of resonant 'sound cave.' The slanted surface directly above the stairs is the underside of the stairs that go the second floor.

IMG_1291.jpeg

I want to leave the general space at the bottom of the stairs how it is with the new finishing. Any great (hopefully inexpensive) DIY solutions come to mind for treatment of this area?


Question 6:

General treatment direction and order of priority. Once I get this area set up and all squared away with the finishing side of things, when it comes to treatment (traps, mid / high freq absorbers / diffusion) I want to make sure I'm on the right track. I haven't done as much homework on the treatment end yet and may start a separate thread after researching this area as much as I can, but so far this is what I've got, in order of priority.
Bass traps first priority - in the corners, larger gap from corner to trap the better. Bigger traps the better, especially for my environment.
Absorption on first reflection points - still not 100% on proper placement, and size of these absorbers.
Diffuser - on wall opposite mixing desk (mixing desk will be on wall opposite the stair wall)
My monitors are K-Roks. These should be on stands and make an equilateral triangle to my ears with tweeters (or bass drivers?) being eye level. Should be decoupled from stands if possible. I've seen a bunch of information on proper placement and distance of monitors but it seems there is a degree of subjective 'play' with this to get the best distance ratio for stereo image?


Question 7:

Drywall. I know I've said this whole thread I'm trying to stay away from it, but TBF also offers an option where they do the concrete / vinyl panel on the bottom, a chair rail and then use purple board (most moisture resistant drywall) on the top.

IMG_0519.JPG

From the finishing end, this looks really cool. Not as durable. Not as easy to repair.

I've read that drywall the ability to absorb a small amount of bass. The drywall in this case would be mounted directly to those Basement to Beautiful EPS foam panels, which are mounted directly to the concrete, so I don't know how much the purple board would resonate and/or absorb bass. From a sound perspective, would there be ANY advantage to using this 1/2 purple board, 1/2 cement / vinyl option? Again, no finishing done yet, no materials ordered as of today.

I think that about covers all the bases for now. Want to thank you guys for being a place where this information is available in public forum. Thank you in advance for any and all help / advice you can give on my project!

[Museth]

As an aside, just found a decent resource if it can help anyone else in my situation, (or anyone else who wants documentation on this sort of thing). The document is called "Controlling the Transmission of Impact of Sound through Floors." Gives a pretty comprehensive coverage of approximate IIC ratings for different floor assemblies and materials. Looks like it was published by the Institute for Research in Construction - National Research Council of Canada. Seems largely fact based / field test minded.

Link:
https://www.nrc-cnrc.gc.ca/ctu-sc/files ... 35_eng.pdf

[Soundman2020]

Hi "Museth", and Welcome!

After about a year and a half in the planning

Please post your complete plans here! If you are that close, and have been working for so long, then you must have some very detailed plans by now. Hopefully, in SketchUp format!

Dimensions: 24 x 12 x 7. Foundation - poured concrete walls, concrete floor. Stairs at the back of the room.

Nice! Except for the height.... 7 feet does not give you much to play with....

Ceiling is unfinished, wooden floor joists are 7 1/2 inches deep

When you say the room height is "7 feet", is that measured to the bottom of those floor joists above you, or the bottom of the sub-floor above the joists?

joists are 7 1/2 inches deep x 1 1/2 inches wide with 14 inches between.

Spacing for joists and studs in construction is always measured "on center", abbreviated "OC", not the gap between them. So you measure from the center of one joist to the center of the next joist. It seems that your spacing is therefore the common standard spacing, of 16" OC.

It is important to use the right terminology and correct conventions in studio design and construction! If you told your builder you wanted joists 14" apart, he would assume you meant 14" OC... Big difference!

I'm going to be using a Sani-Dry dehumidification system for water vapor / humidity control and air purification. Air quality and smell is also very important for my students and parents and for my own children as well.

You want to use this studio for recording acoustic instruments and vocals. Therefore your dehumidifier will have to sit OUTSIDE the actual isolated studio space, and be integrated into your HVAC system for the studio (yes, you do need one). It cannot go inside the studio. Considering that the HVAC system itself will dehumidify the air (that's part of what it does anyway), it would probably be a good idea to wait until the room shell is completed and the HVAC system is in place, then test it to see if teh HVAC by itself is doing a good enough job for your goals. If not, then you can incorporate the additional dehumidifier into the HVAC circuit.

In other words, no wood, drywall or paint if it can be avoided,

That pretty much limits you to metal framing and fiber-cement or engineered wood sheathing, but it's going to be a challenge to do most of the rest without using wood! I noticed that your desk is wood, and has a wood platform for the computer... what will you be using for your final desk, that is not made from wood?

(treatment will be added after all the initial finishing work is done).

It seems to me that you are setting unrealistic goals without yet understanding how the studio design and construction process works. Saying that you can only install treatment after the room is finished is like saying you want to build a car but insist on only deciding what chassis to use once the engine and gearbox are already installed...

for example wire through the wall or ceiling later if needs change.

Not a problem: run all your cabling through conduit. Make it large diameter and keep the curves gentle. Not an issue. Chepa, simple, effective.

2 1/2" thick EPS graphite-infused panels ... prefabbed with electrical chases,

That won't work very well for adding or changing wiring!!!! Conduit provides a direct and smooth path: you can pull new wires or cables through any time you want, and pull old ones out. But not with the system you show there... that's a permanent system. Zero flexibility.

Walls durable enough for 8 year olds accidentally banging guitar cases into them and not dent.

Unrealistic. Acoustic treatment is frequently soft, light-weight, and fabric covered. That can usually be protected with wood slats placed at strategic locations to minimize damage, ... but you have rejected wood as an option. I would suggest painted MDF slats, but you also rejected paint.... I guess the only answer here is aluminium or steel slats, but that's going to make your treatment extremely heavy, and extremely expensive...

I spent about two years looking at different finishing options (drywall, wood, carpeting,

Carpeting ? In a studio? Nope. Bad idea. Especially if you have health issues related to air and humidity.... And even worse acoustically. Carpeted floors have no place in a control room.

They roll it out in about a week.

Color me skeptical on that one! I have NEVER heard of ANY studio being built in a week. My personal best record is three months, from first contact with the customer up to the day the studio opened for business. And that was 3 months of hectic hell, with a 6-man construction team. It took a week just to tune it....

These are 2 1/2" thick EPS graphite-infused panels

What are the acoustic specs on those? Specifically, the coefficients or absorption at 1/3rd octave intervals? Without that, it's impossible to say if they would be any use in studio walls or not.

wall panel. It is a 1/2 inch cement board

That's fine. No problems there. I use that stuff occasionally in studios. Heavy, expensive, brittle, nasty to work with, but good high density.

impossible to dent,

Actually, that's not true. I use fiber-cement board frequently in my builds, and it CAN be dented. Drop a hammer on it, for example...

anything can be mounted anywhere - rigid enough to mount a flat screen or bookshelf from, regardless of stud placement

That's not true either. Light-weight objects can be mounted like that, but heavy things would need additional support. Fiber-cement board is brittle.

Floors:
Carpet Tiles - They call it ThermalDry

Carpet???? On a studio FLOOR??? You are kidding, right? Are you not aware that carpet does the exact opposite of what a studio needs, in terms of acoustic treatment? this is a REALLY bad idea. Skip that, and use laminated flooring instead, or ceramic, or vinyl.

Floating interlocking carpet tile floor matting system that creates a airspace between concrete floor and your feet with spacers on the bottom of the tile.

So let me get this right: You plan to have resonant cavities under your flooring? Are you serious?

A. Isolation - (impact noise from above and my noise from below at 3AM in the morning w late night mixing session)

The best, easiest and cheapest way to deal with impact noise is at the source, not the destination. Put some type of thick resilient floor covering in the room above. Problem solved at low cost.

If you don't want to do that, there are other options, but the cost skyrockets.

B. Absorption - high / mid freq absorption, some bass trapping would be a bonus.

You have that completely backwards! You do NOT need high or mid absorption in your ceiling. You absolutely DO need bass trapping. Abundant bass trapping. It's not a "bonus": it's the main purpose!

This is the same reason why carpeted floors are a terrible thing for studios. Carpets are excellent at absorbing highs, mediocre and random at absorbing mids, and don't absorb any lows at all. What studios need is major, big-time, huge bass absorption, some controlled mid-range absorption, and little to no high absorption.

D. Doesn't sacrifice precious ceiling height and close off duct work and wiring.

Unrealistic. If you want isolation for your room, you have zero choice here. The ONLY thing that stops airborne sound from getting from point A to point B is hermetically sealed mass. The more sound you need to stop, the more mass you need. the lower frequency the sound is, the more mass you need. That is simple mass law: ( Tl = 20 log (F * M) - 47 dB (where F is the frequency (Hz), M is the mass per unit area (kg/m²) ).

So you have to decide: Do you want to have all the noise from your house getting in to your studio, down through the floor above you, piped through the HVAC ducts, and through the electrical system? Do you want to have all your own studio sounds from getting back up into the house through the same paths? If your answer to both of those is "", then you WILL have to put some type of reasonably massive ceiling up there, on resilient mounts. It does not have to be extremely thick, but it will take up a couple of inches. Less than an inch is impossible. If the answer is "yes" to the above, then you can skip the massive ceiling, and just use fabric. No isolation, but great acoustics.

As far as the impact noise, I plan to eventually add some thick carpet in the living room to soften footfalls but I realize that without adding mass, I can't do much on that end

You DON'T need mass there. That is impact noise (structure borne) not airborne. Thick carpet on a good acoustic underlay will be an excellent method of sealing with the impact noise from footfalls.

Drywall for the ceiling is not an option.

Then isolation for your room is not an option. Sorry. It really is that simple. No sealed mass = no isolation.

It closes off ductwork / electrical

Yes. Which is exactly what it needs to do in order to isolate! HVAC ducts are a MAJOR source of flanking paths. That's why studios need their own separate HVAC system that is independent of the building HVAC, or tied to it through silencer boxes and vibration decouplers. If you have the house HVAC ducts exposed to the studio, you will have all the house sounds getting into your studio, and all your studio sounds getting into the house.

and absorbs very little,

Huh??? "Dyrwall absorbs very little"???? I don't agree with that at all. Drywall makes a great absorber, when used in panel traps.

Contractor also does not offer it as an option so I'd have to do that myself.

Contractor DOES offer 1/2" fiber-cement board... you said so yourself. Hang that on resilient channel (or better still, on hat channel in RSIC clips), and your ceiling isolation problems are solved.

they offer a drop ceiling option with 2 x 2 foot .55 NRC mineral fiber tiles from USG.

Useless. NRC is not about isolation: it is about treatment. That shows you how much sound the tiles absorb, overall, not how much transmission loss you can expect for sound passing through them, which is a very different thing. NRC of 0.55 will give you a TL of maybe 3 dB or so, if you are lucky. A properly done drywall or fiber-cement ceiling will give you at least 40 dB, perhaps 50 dB. Real isolation.

From most of the folks in a similar situation on these forums, it seems the recommendation if there is a choice is to skip the drop ceiling entirely in favor of ceiling height.

Yes: Correct. And also because "acoustic drop ceilings" are useless for studios. That's not what they are meant for.

Also read that these tiles are great for office environments, but poor for high-frequency absorption.

Wrong. They are great for high frequency absorption, and lousy for low frequency absorption. Yes, they are great for office environments, for the same reason: offices don't have low frequency transmission problems, and they do have mid and high frequency problems, where acoustic ceiling tiles do a good job.

Ethan Winer suggested, " pull out the grid, which will give you more height, and pack the cavities between joists entirely with fluffy fiberglass. Then you can staple fabric to the joist bottoms, and add thin wood trim strips to cover the staples. This will be much more absorbent at high frequencies than any ceiling tile, and all that fiberglass will give a nice amount of bass trapping. It will also cost less than replacing one grid with another, and is probably less work too."

True. But that's treatment that Ethan is talking about, not isolation. They are two very different things. that will help with your bass problems, yes, but it will do nothing at all to solve your isolation problems. You will still get all the noise from upstairs, all the noise coming through the HVAC duct, and all the noise coming through the electrical system, plus all your noise will still be taking the same paths in reverse, up into the house.

"With my seven foot ceilings, I would like to make the control room ceiling "disappear" as much as possible, both acoustically and visually" where he mentioned the insulation / cloth idea as well. I've seen this idea echoed by a few others.

Same issue. Great acoustically, but zero isolation.

and he said they could just paint the ceiling with black Dryfall.

Why bother painting it, if it wll be covered in fabric? You won't see much through the fabric....

So…with the desired sonic goal of the space (control room dynamics -acoustic neutrality, pretty dry),

It cannot be both! Ether it is acoustically neutral, or it is acoustically dry. They are mutually exclusive terms. Saying a room is both "dry" and "neutral" acoustically is like saying it is both filled with warm sunlight but also pitch dark inside....

Control rooms should indeed by acoustically neutral, and they should never be dry. Even "half dry" turned out to be a terrible idea, as evidenced by the failure of the LEDE concept, decades ago.

am I on the right track with the solution of insulating the joists and then stapling fabric to the joists?

No. And yes. If you are happy to forget about isolating your studio form the rest of the house (in both directions), and ONLY want to treat your room, then yes, that would be a small part of providing the bass trapping that you will need on your ceiling, since it is so very low. You would also need to have a layer of plastic between the insulation an the fabric, to prevent fibers filtering down all over you and your gear over time, and also to reflect back some of the high-mids and highs that would otherwise have been over-absorbed by the excessive insulation.

If so, is it better to use Roxul (and specifically what kind),

The type that has a density of around 50 kg/m3, if you are taking about mineral wool, or the type that has a density of around 30 kg/m3, if you are taking about fiberglass. Better still, look for stuff that has a gas flow resistivity of around 10,000 to 15,000 MKS Rayls, since that is the actual parameter that defines acoustic absorption.

My decision to use TBF's carpet tiles was based on several factors:

... perhaps, but the one you forgot to include is "good control-room acoustics". Carpet has no place as flooring in a control room, for the reasons mentioned above. It does the opposite of what you need.

The company has three other options - wood plank vinyl flooring, vinyl tile (ceramic look),

All of those would be fine. Except....

All options create the air pocket off the floor which provides the thermal break.

... so all of those would NOT be fine! Air cavities are resonant systems; they RESONATE! You do not want a bunch of resonant systems under your floor.

Just lay plain old laminate flooring over plain old closed-cell laminate underlay: It has all of the advantages you mentioned, is cheaper, and is also excellent acoustically.

but absorption as a mentality for a control room (esp a smaller one with low ceilings) is favorable.

Yes, provided that it is controlled absorption, and provided that it is NOT on the floor. Having acoustic absorption on the floor is also a bad idea psycho-acoustically: it messes up your brains ability to determine directionality, as well as ambiance. Studios almost always have reflective floors, for this reason.

Besides, with your highly absorbent ceiling, your floor should be reflective anyway...

If I do the ceiling with the Roxul and fabric and use the carpet tile from the floors, there would be a good deal of absorption from that.

Way too much in the highs, not controlled, random, not balanced, not neutral....

From what I understand, you don't necessarily want any room TOTALLY dead.

Absolutely not! The acoustics of a control room should meet the ITU, AES, EBU, etc. specs for control rooms. That sets out exactly what the decay time should be, as a function of room volume and frequency band, as compared to the "standard" reference room.

The equation is:

0.2 < Tm < 0.4 s,

where:

Tm = 0.25(V/V0)1/3 s

and V0 is the volume of the 100m3 reference room.

The spectral decay is then tuned like this:

"reverberation times between adjacent 1/3–octave bands should not exceed the following limits:
< 0.05 s for 200Hz < f < 8 kHz
< 25% of longer time for f < 200 Hz"

The wall vinyl coverings are hard, reflective and probably insignificantly diffusive because of their slightly raised varied alligatored texture.

Which is why they make for a terrible control room wall....

Given the materials they offer, am I on the right track with these carpet tiles for what I want to accomplish with the space?

No.

you can see that it's pretty much a 12 x 24 rectangle.

... which implies that it will have severe modal issues, since the length is exactly double the width. All the even order modes in one direction will line up exactly with the odd-order modes in the other direction: modal hell. That's why control rooms are never designed with dimensions that are directly related mathematically.

Control room would function as the lesson room and tracking area as the waiting area. When I investigated the potential sound physics / consequences of the splitting idea however, (standing waves, room nodes, sound pressure), the general wisdom seemed to be, it may look / seem cool in your head, but better to have a big space the LF big waves.

You have 288 square feet of floor area to play with. the above-mentioned specs say that a control room should have about 200 to 650 square feet. You have plenty of space. John has built excellent control rooms inside shipping containers! I have built successful control rooms in less than 200 ft2. It can be done. Especially when you would otherwise have major modal issues due to the problematic ratio.

The "other" room does not have to be big: jut large enough to seat a couple of people who are waiting their turn, with their instruments. Taking off a small space just a few feet wide and 12 feet long would be an option. Taking 4' 11" off for that and allowing 6" for the dividing wall, would give a CR that is 18'7" x 11' x 7'7", which is very close to Volkman's ratio, passes all three BBC critical tests, has smooth modal distribution, and a room volume of over 1500 cubic feet, which some designers use as acceptance criteria. The floor area is 204 square feet. Not a problem.

The question is, based on my goals with the space, is this (one big room instead of two smaller ones) the right starting call pre-treatment to achieve the best acoustic neutrality and least pressure issues?

You could go either way. Personally, if that were my room and I had a need for a waiting area / storage area, I'd do it like that. It also takes that acoustically terrible stairwell out of the equation

The entire basement is a square, divided by a poured concrete support wall that divides the square into two equal rectangles with 12' length

So how are you going to remove those walls, to get the full 24' length? Or maybe you are not describing this very well....

I would describe noise coming from this room at its' loudest point as moderate at most - not horribly loud or annoying at all.

That's a subjective assessment. You are going to need a sound level meter to check the actual levels, in decibels.

Best value for the dollar above standard hollow-core.

Hollow core doors are never used for serious studio isolation. They are low in mass, resonant, and lousy at isolating. Solid core doors is the only way to go. You will need two of them, placed back to back, with a small air gap between them. One goes in the outer leaf, the other in the inner-leaf. If you don't what to use two, then you can do it with one "superdoor" instead. That is a very massive door (extremely heavy) that is built up from a standard solid-core door, with extra layers of mass on it, and heavy-duty hinges to handle the huge weight.

Any great (hopefully inexpensive) DIY solutions come to mind for treatment of this area?

Use that as your waiting room area. It's an acoustic nightmare, and excluding it from the actual studio with a dividing wall is the only realistic solution.

Once I get this area set up and all squared away with the finishing side of things, when it comes to treatment (traps, mid / high freq absorbers / diffusion) I want to make sure I'm on the right track.

Treatment is not an after-thought that you can sort of tag onto the end of a control room building project!!! This is a CONTROL ROOM we are talking about! It needs to have the acoustic properties of a control room, as laid out in those documents I mentioned. That does not happen by accident, nor by throwing in a few bits of treatment after the fact. It starts by designing the room to actually be a control room. The treatment starts with the initial layout and geometry of the room. The complete room must be designed from the start, with the treatment included. When you initially said that you had spent a couple of years on designing the room, that's what I though you meant, since that is about how long it typically takes a project studio builder to do it. About 6 to 8 months to learn the basics of acoustics, another 3 to 4 months to learn the basics of construction, then another 3 to 4 months to do the actual design. Roughly a year to a year and a half in total. But it seems that your year and a half has been spent in researching materials that you like, and builders that use them. So it seems you still have another stretch of learning and designing ahead of you!

I haven't done as much homework on the treatment end yet and may start a separate thread after researching this area as much as I can,

To get you started, I'd suggest two books: "Master Handbook of Acoustics" by F. Alton Everest (that's sort of the Bible for acoustics), and "Home Recording Studio: Build it Like the Pros", by Rod Gervais. The first one ("MHoA") will give you the basics you need to know about how sound actually works in the real world, with the basic math you will need to calculate your room acoustic. the second one gives you the details of how to actually design the structure of the studio itself.

Bass traps first priority -

No. Room layout and geometry is first priority. Get your mix position, speakers, desk, chair, rack gear, and furniture in the optimal locations. then adjust the location of doors, windows, and HVAC to fit around that. THEN you can start thinking about bass traps. It makes no sense to prioritize bass traps when you don't yet know where they will go...

Bass traps ... in the corners, larger gap from corner to trap the better. Bigger traps the better, especially for my environment.

Do superhcunk bass traps. The best, by far. And try to hit as many corners as you can (there are twelve...). Allow for covering the bass trap faces with plastic or a similar type of membrane, to reflect back most of the highs and mids, so that the room is not over-damped, and you get get the response balance outlined in the documents I mentioned above.

Absorption on first reflection points - still not 100% on proper placement, and size of these absorbers.

Once you get your room layout done (correct geometry), and considering the angels and the Q of your specific speakers, all of that falls into place automatically.

Diffuser - on wall opposite mixing desk (mixing desk will be on wall opposite the stair wall)

Why do you think you need a diffuser there? What type will it be, and what range will you tune it to? What coefficients are you looking for? How will you take into account the fact that you'll be playing instruments close to that? You might be able to get it far enough away from the mix position that the Cox and D'Antonio parameters are met, but I doubt you'll be able to do that with respect to the locations where you'll be playing....

My monitors are K-Roks. These should be on stands

Yes: Very massive stands that are tight up against the front wall, except for a 4" gap to allow for the SBIR absorption panels.

and make an equilateral triangle to my ears

False. The apex of the triangle needs to be about 12" to 18" behind your head, such that the acoustic axes are pointing just outside your ears, not into your eyeballs! That maximizes the sweet spot, and gives you a good sold sound stage with clear stereo image.

with tweeters (or bass drivers?) being eye level.

False. The acoustic axis of the speakers needs to be be at ear level. Sort of obvious when you think about it, but so many "expert" sources on the internet get it wrong. The acoustic axis of the speaker is the point from which the sound seems to emanate, and is on the imaginary line that joins the center of the woofer to the center of the tweeter. It is much closer to the tweeter than the woofer. Most manufacturers provide diagrams that show where the acoustic axis of their speakers is. Imagine a line extending out from that point, perpendicular to the front baffle of the speaker. That is the acoustic axis, and that is what needs to be at the same level as your ears, which is 1.2m above the floor for most people, when seated. It's obvious that the speaker needs to be aimed at your ears, so I just don't get why so many "experts" think it should aim at your eyes... That would be fine if your ears were located inside our eyeballs, but humans are not made like that...

Should be decoupled from stands if possible.

Not "if possible". They MUST be decoupled from the stands, and the stands must be very massive.

I've seen a bunch of information on proper placement and distance of monitors but it seems there is a degree of subjective 'play' with this to get the best distance ratio for stereo image?

Not really. It is to get the smoothest frequency response and time domain response form the combination of speakers + room, at the mic position. There are guidelines on where to place the speakers (in terms of distance from side walls, and angles), and where to place the mix position (in terms of distance from front wall). You start from that location and test slight variations on it, such as seeing if the response is smoother at several points a few inches apart going forwards and backwards from that initial location, then adjsuting the distance of the speakers slight further apart and closer together, also in increments of a few inches, to find the optimum position, then adjusting the speaker angles back to the correct geometry for that final location. You do all of that with the REW acoustic software package and a proper acoustic measurement mic, analyzing the data, moving things around, then confirming the final position with your ears.

Not as durable. Not as easy to repair.

Actually, drywall is dead easy to repair! Patch with drywall "mud", sand, paint. Done! It's a lot easier than trying to patch fiber-cement board that has a patterned vinyl laminate finish on top....

I've read that drywall the ability to absorb a small amount of bass.

And large amounts too....! Drywall actually makes a great membrane trap, when tuned correctly.

The drywall in this case would be mounted directly to those Basement to Beautiful EPS foam panels, which are mounted directly to the concrete,

Then it won't do much like that. And it is impossible to calculate without knowing the acoustic properties of the foam panels... If you can show the test results from when those panels were tested in an independent acoustic lab, then I can tell you how well drywall would work as a bass trap over those.

From a sound perspective, would there be ANY advantage to using this 1/2 purple board, 1/2 cement / vinyl option?

There might be, but you seem to be confusing the issue of isolation and treatment again. The walls of a room will absorb a small amount of bass, yes, but the MSM system is tuned so that the resonant frequency is an octave below the lowest frequency that you need to isolate, so the effect is minimal at best, regardless of the materials used. It' the design that counts, not the materials. The design takes into account the properties of the materials, and uses them on such a way that the do the job that is needed. Not the other way around.

The document is called "Controlling the Transmission of Impact of Sound through Floors."

That's a good basic overview, yes. It's one of many similar documents put out by the NRCC, most of which go into a lot more detail. Others that you should look at are: IRC-761, IR-25, IR-56, IR-766, IR-802, IR, 586, IR-693, and IR-754, IR-832, : All of those are pertinent to the questions you have asked. You should work your way through all of them, to better understand the issues and factors involved in isolating a room.

- Stuart -