John Sayers' Recording Studio Design Forum Archive

Hi all,

First, thanks for taking time to help me. This has been a long-time dream of mine, and hopefully--with the wife's approval--I can start making it a reality.

I'm looking to build a rehearsal studio in my house. Just a live room for now, as recording is very much a second priority for me. I will probably add a control room eventually, but it's not on my list for the moment. A picture of the space and a proposed diagram are attached. The picture is taken from the north-west corner of the below diagram, facing the center of the room.
The floor and walls are poured concrete. The walls are wrapped with 3-4 inches of fiberglass insulation. The ceiling has 1/2 inch drywall, screwed to 2 x 12 inch wooden "I" beams (I've never seen these things before and have a had time describing them) spaced 20 inches and running north-south on the diagram. There is no insulation between the beams. The ceiling is 7 feet, 9 inches off the floor. The blue boxes on the below diagram are ducts running along the ceilings (one of which is visible in the above picture)--they hang 8-10 inches below the existing ceiling. There is an escape window on the north wall about a foot from the western corner that is 4 feet wide and 4 feet tall; it sits 30 inches off the existing floor; it must remain unobstructed.

Acoustically, I need the inside to sound decent for electric and acoustic guitars, saxophone, and (one day) a baby grand piano. I know that is a subjective standard, but I cannot think of an objective way to describe it. As for isolation, the family room (which is directly above the proposed studio) has ambient noise at about 60 dbs. With a guitar amp generating 115 dbs in the basement (4X12 cab, placed near the north-east corner of the stairs and facing the center of the room), a spl meter in the family room registers 75 dbs. Ideally (and I understand ideal is usually not possible on a budget) I would like to keep the ambient noise in the family room at the same level with any of the above instruments generating those levels. I am very much an amateur at this, and if this is not in the realm of possibility, please let me know.

As for budget, I am looking at ~$1500 to $2000 USD; but this is a target and remains somewhat flexible. I can do most work myself, but will likely need to hire help with the high-voltage electrical. I plan to spread the construction out over the next year to 18 months. It will certainly be an on-the-weekends project.

No construction is done yet. I am in the planning phase.

Here's the plan I've developed so far: Walls adjacent to the outer walls will be studded 6 inches from the poured wall--wooden 2x4s with a layer of 1/5 inch drywall. Interior walls will be doubled with 4 inches between the studs--again, wooden 2x4s with 1/2 drywall on each face. An exterior door goes on the south wall of the diagram at the eastern corner of the studio. The current drywall on the ceiling will have to come down (to avoid a three-leaf system); I will install resilient channels and a layer of fiberglass insulation as the respective manufacturers prescribe. Floor will be covered with Delta-FL sheet, laminate padding, and a 12mm laminate flooring. As for acoustic treatments, I plan to build homemade bass traps (the ones made with two sheets of fiberglass insulation and steel studs--see Glenn Fricker's youtube channel) and pace them four per long wall, staggered so that they are not directly a cross from each other.
First question: Is this a feasible plan? Will it achieve the kind of performance I am looking for? Is there something I am overlooking or being naïve about?

Second question: How do I isolate and ventilate a room? How can I build any necessary features for the HVAC system into the design?

Final question: I am concerned about the concrete floor; will adding a layer of 1/2 inch tongue-and-groove chipboard offer an improvement? Would it be worth the price?

Thank you again, and please excuse any spelling errors.

Hi Dan, and Welcome!

2 x 12 inch wooden "I" beams (I've never seen these things before and have a had time describing them)

You mean something like this? If so, those are engineered wood joists, or I-joists.

spaced 20 inches

You mean spaced 20 inches ON CENTER; or 20 inches measured between adjacent joists? With framing, the normal way of measuring is from the center of one joist to the center of the adjacent joist, often referred to as "OC". I suspect yours might be 24" OC, or some such.

The ceiling is 7 feet, 9 inches off the floor.

Ouch...

Acoustically, I need the inside to sound decent for electric and acoustic guitars, saxophone, and (one day) a baby grand piano.

It can probably be OK for the guitars, maaayyyybe for the sax, but I can't see a baby grand sounding good in a room with a 7' 6" ceiling. I'm not trying to be a wet blanket here, but that's the sad truth. Pianos, drums, and several other instruments need height (and space in general) to sound good.

As for isolation, the family room (which is directly above the proposed studio) has ambient noise at about 60 dbs

Not sure what "dbs" is, or how you measured that, but we'd need to know the measurement in dBC, slow response. Pretty much all SPL measurements in studios are done with dBC and Slow.

With a guitar amp generating 115 dbs in the basement (4X12 cab, placed near the north-east corner of the stairs and facing the center of the room), a spl meter in the family room registers 75 dbs.

Once again, you'll need to repeat those measurements using dBC and Slow. I've never heard of dbs. Based on that, it seems that you have about 40 dB of isolation right now, which is unusually high for just a typical house floor on I-joists with no insulation, so that's suspect to start with, .... and you need at least another 15 dB, to get down to 60 dBC upstairs.... but 60 dBC for ambient is also unusually high, so you likley need more. Assuming that you want to play screaming guitars downstairs, and don't what to hear it at all upstairs, you'd probably need about 55 dB of isolation, or more.

Ideally (and I understand ideal is usually not possible on a budget) I would like to keep the ambient noise in the family room at the same level with any of the above instruments generating those levels. I am very much an amateur at this, and if this is not in the realm of possibility, please let me know.

It might be possible, but it will be a tall order. And first we'll need to get those measurements in dBC Slow, not dbs.

As for budget, I am looking at ~$1500 to $2000 USD; but this is a target and remains somewhat flexible.

Assuming that upi do need 55 dB of isolation, your budget is not realistic. Your room floor area is about 280 ft2, and you plan to spend US$ 2000, so that implies US$ 7.42 per square foot. Assuming you want to use something like ordinary laminate flooring in your finished room, US$ 7.42 per square foot is roughly what that would cost. Just for the flooring: no walls, ceiling, doors, windows, HVAC, electrical, room treatment, etc. That's JUST for the flooring. The installed cost for JUST a single layer of drywall all around your room (four walls and ceiling) would be around US$ 1,500, but you will need at least two layers, since you need high isolation, so figure at least US 3,000 for that. That does NOT include the stud framing or the insulation: that's additional. It's JUST the drywall itself, plus installation materials and labor. Allow about US$ 8 to US$ 10 per square foot for framing (very rough estimate), so with 280 square feet, that would be around US$ 2,800. Then there's doors, windows (if any), the electrical system, the HVAC system (yes you do need it), and the acoustic treatment. For what you want to do, I would estimate that you'd need a budget of around five times what you are estimating right now. Somewhere around US$ 10,000 would be about right. Ball-park. So roughly US$ 35 per square foot of floor area. If you really shop ver, very carefully for your materials, and do most of the work yourself, you MIGHT be able to get that down to maybe US$ 25 per square foot, with a bit of luck, but I don't see it going lower than that....

Sorry to be the bearer of bad tidings...

Walls adjacent to the outer walls will be studded 6 inches from the poured wall--wooden 2x4s with a layer of 1/5 inch drywall

Why did you choose a 6" air gap, and what is "1/5 inch drywall"? I have not heard of that rather unusual thickness. And that's VERY thin! No use for isolation. Normally, you need at least two layers of 5/8" drywall.

Interior walls will be doubled with 4 inches between the studs--again, wooden 2x4s with 1/2 drywall on each face.

That sounds like you are wanting to build a four-leaf wall? Two stud frames, and each of those has drywall on BOTH sides? That would trash your low-frequency isolation. Only ever build two-leaf walls. Never one leaf, never three leaf, or anything else, unless you absolutely have no choice. And if that's the case, then you'll have to compensate or the greatly reduced isolation by increasing the mass on the leaves, and using larger air gaps. That's the only way to get the resonant frequency of the wall down low enough. 3-leaf anf 4-leaf walls are a problem. Avoid.

An exterior door goes on the south wall of the diagram at the eastern corner of the studio

... you are planning on having TWO stud-framed walls, so you will need TWO doors: back to back, one in each frame.

The current drywall on the ceiling will have to come down (to avoid a three-leaf system); I will install resilient channels and a layer of fiberglass insulation as the respective manufacturers prescribe

If you need high isolation, you won't get it with RC. And the manufacturer of the RC won't specify anything at all about the insulation that you need to use. That's a function of the isolation system that you design. The insulation must be the correct type for the job. In this case, for the wall and ceiling cavity, and since you already decided that it must be fiberglass (as opposed to any other type), it will need to have a density of around 30 kg/m3, or a little less.

Floor will be covered with Delta-FL sheet, laminate padding, and a 12mm laminate flooring.

.... and there goes your entire budget! Just for that. Go down to your local Home Depot and quite 12mm laminate flooring, installed, including slab leveling and underlay...

As for acoustic treatments, I plan to build homemade bass traps (the ones made with two sheets of fiberglass insulation and steel studs- see Glenn Fricker's youtube channel) and pace them four per long wall,

I'm not sure who Glenn Fricker is, but I'm guessing that he is not an acousticain.... If you found acoustic treatment design advice on YouTube, chances are about a million to one that it is not very good advice. To start with, you talk about making "bass traps" that you will place against your walls... well you can't have it both ways! If they are along the walls, they are not bass traps. If they are bass traps, then they are not along the walls. The simple fact that someone told you that bass traps are panels that can be hung on walls, shows that you have been mislead. You can have acoustic absorption panels on the walls of your room, and will certainly need them, yes, for various purposes, but none of those purposes is bass trapping. Bass traps go in corners not against walls. Bass traps are huge, massive, deep, thick, and are at their most effective when placed in corners. You CAN put them on the walls if you want, as long as you don't mind things that stick out a couple of feet from the wall, and are about 50 times less effective anyway due to being in the wrong location.... Or you could put them in the corners, where they can be anywhere up to 18 dB more effective than against a wall...

staggered so that they are not directly a cross from each other.

So you are planning to treat flutter echo with those panels? So they aren't bass traps? The type of treatment that is usually "staggered" (more correctly "checke-rboarded") is the type that treats flutter echo. Why do you think you will need to treat flutter echo? Did you find that on YouTube?

First question: Is this a feasible plan? Will it achieve the kind of performance I am looking for? Is there something I am overlooking or being naïve about?

It is achievable to get high isolation for a basement, yes. Many forum members have achieved that. But it can't be done on seven dollars per square foot of floor area.

I would start be re-measuring your SPL levels, using a calibrate meter set to dBC and Slow. Take many measurements, all around the house, not just directly above. Then turn everything off, wait for the quietest time of night, when it is deathly silent, and measure that level as your real ambient level, at all the same places where you measured before. I can guarantee that it is not 60 dBC.

Then compare your highest number (level inside the room with the cap on max, puffing out smoke along with noise...), against your lowest number. That's how much isolation you need. That's your most basic number, and defines how you need to build your walls, ceiling, doors, windows, HVAC and electrical. IT defines your budget.

Second question: How do I isolate and ventilate a room? How can I build any necessary features for the HVAC system into the design?

You will need to build silencer boxes that allow the air to flow through but block sound. You need to do a lot of math to calculate how to design those. They are large, and heavy, and take up a lot of space, so they DO need to be incorporated into the design. In some studios that I have designed, I have managed to fit those up in the joist space above the room, so they don't actually take up any space from the room itself: it MIGHT be possible in your case... It might not.

Final question: I am concerned about the concrete floor; will adding a layer of 1/2 inch tongue-and-groove chipboard offer an improvement?

An improvement to what? What are you trying to improve by adding chipboard?

Summary: It is feasible to build an isolated room in that space. It's a decent size. The ceiling is very low, and places limitations on the final acoustic response. It might be suitable for acoustic guitar, electric guitar, perhaps for vocals, perhaps sax, but not drums and not piano. The budget is way short. If you increase the budget, and plan carefully, then yes, it is possible.


- Stuart -

Also, to add to what Stuart replied:

You said your current ceiling height is 7' 9". In order to achieve the high levels of isolation you've stated, undeniably you're going to have to build your space as a room in a room type design. As Stuart said, the RC will not provide you with that amount of isolation at the troublesome lower frequencies as the system ultimately does couple your drywall to the joists above.

Building a room in a room means building a fully de-coupled MSM system. That means that your inner leaf ceiling (the ceiling of your inner room) cannot touch the joists above, period. The way you build this is by installing new ceiling joists that sit on your inner leaf wall frames. Now, in order to legally span your 14' distance (the shortest distance in your design), I'd put money on it that you'd have to use 7 1/4" deep LVL stud. By the way, legally, you need an engineers stamp for this. Often, suppliers won't even sell you this stuff without the stamp. And the first thing your framing inspector will ask for is the paperwork with the stamp on it.

So, to take any deflection of your existing floor above into consideration, let's leave a 2" gap between the existing joists and your new LVL stud. Here is your new visual ceiling height:

7' 9" - 2" (deflection) - 7 1/4" (LVL stud) = 6' 11 3/4"

Now, this is assuming you're building your ceiling using John Sayer's "inside out" method which is the best way to save ceiling height. Inside of the LVL stud skeleton, you would install modules that have OSB (for structural integrity) and 2 layers of 5/8" drywall on them. Sealed to hell and back of course!

If you go the "easier" route, add 1 1/4" (for your two layers of drywall) and then 5 1/2" (which is the depth of 1x6 dimensional lumber that you'd probably use to frame up acoustic panels for your ceiling). First off, this wouldn't look as nice, wouldn't perform as well acoustically, and it would drastically lower your ceiling height both acoustically AND visually.

Here's the "easier" method's finished visual ceiling height
6' 11 3/4" - 1 1/4" - 5 1/2" = 6' 5"

So, know that those are your finished ceiling height options.

The ceiling for the spots of your basement with the HVAC trunk running along it need to be addressed. Those will cause a major issue with your plan. This is because you will need your walls to hold up your LVL stud joists and the trunk will prevent you from having those walls structurally hold up the joists. You'd either need your wall frames designed and approved by a structural engineer such that they could "reach out" and hold up the ceiling weight "around" the trunk, OR you have to build your entire ceiling below that trunk. Therefore your new ceiling height would be the figures I wrote down above minus 10 inches. Yes, do that math

Lastly, I feel I should point out some things regarding HVAC since I've transitioned to that topic in the last paragraph.

Stuart said that the silencer boxes you'll need are large. I'm not sure if you realize just how large these things are. And I'll tell you this: I will put money on the fact that you won't be able to fit them above your room in the existing joist spaces. You MIGHT be able to fit one of the 4 needed up there if you split it up into 3+ individual boxes. The other 3, or maybe all 4, will have to live either inside your inner leaf, outside your outer leaf, or between your leaves. Chances are, this will add another foot or so to your overall footprint. That means your room either gets smaller by a foot, or bigger by a foot.

Regarding heating and cooling, supplying fresh air and removing stale air, tapping into your existing HVAC system may or may not be an option. First off, your silencer boxes are going to drastically increase the static pressure of your system. Now, if you design them wisely, you can decrease the static pressure, but in order to do so, the footprint of the boxes becomes much larger -- to put that into perspective, basically consider the fact that doubling the size of the box will halve the static pressure. Now, the fan in your existing air handler unit was sized according to what is currently in your basement. That probably means a single 4" duct that realistically introduces next to nothing in regards to static pressure. Around here, even though we have extreme heat and extreme cold, every house I've seen has horrible HVAC implemented. Personally, my basement is ~1000 sq ft and it has two 4" ducts. Crazy crappy. My in laws house has 3.

To have the recommended 6+ air changes per hour for your room, chances are, you're going to need a 6 or 8" duct. If you figure out the CFM and cross sectional area of those ducts vs a 4", you'll realize that their size increases exponentially. What I'm getting at is that if you tap into your existing house system, chances are you will overload the fan in regards to static pressure and you will also cause the rest of your house to not be supplied with it's designed flow rate as you'll be stealing so much of it for your room. Most home studios use ductless mini splits or designated air hander units.

As a tip, ductless mini splits work great in situations like this because the silencer boxes can be much smaller. This is because the silencer boxes are only exchanging ~30% of the air in the room as where a ducted system is exchanging 100% of the air. Where I live, mini splits cost a small fortune. Where I live, I couldn't buy and install a brand name (like LG) mini split for your room for under $5000 Canadian. Sadly, a good AHU will run me about the same. That leaves no-name crappy brands as an option for us and trying to do everything but pressure testing and commissioning the units ourselves. Food for thought anyway!

Note: don't think you can just not do the HVAC of your room. First off it's illegal and secondly, it's very unsafe. A lot of YouTuber's builds are like this and they think they can just open the doors now and then, but physics proves that doesn't work.

Have you ever looked into www.two-notes.com

That could be a cheaper solution for recording loud guitars. Piano, well, that never going to sound good in a basement anyway. And sax and acoustic would be the only problem remaining. Depending on how great you want them to sound, you could build a smaller, cheaper room in an area where the HVAC trunk isn't hanging down and you can maintain ceiling height.

Greg

Thank you both for the replies. As I'm sure you anticipated, this looks like it is not possible at the moment, given the low ceiling height especially. Maybe when we build a house I can make a few small adjustments that will make this much easier--not having the hanging ductwork or the low basement ceiling, for example, or building the HVAC system to properly ventilate the basement and make it easier to tap into. But I am where I am for the next few years.

I really appreciate both of your thoroughness. I know lots of people come here and react like children when their dreams of an in-home studio are dashed by reality, but I would much rather find out now, before I've spent thousands of dollars on a plan that will not work. Now I will be much better prepared for the next time around.

Thanks again.

No problem, Dan! That's what the forum is all about: bringing studio designs to reality, but also bringing reality to studio designs.

If it is any consolation, that space would probably be usable for a control room, much more than for a live room / rehearsal room. Control rooms can survive with lower ceilings, albeit not ideally. I've done a couple with low ceilings, and it's a real challenge to get right, but they can be made usable. They also generally don't need as much isolation as live rooms, so less hassle with multiple layers of drywall, large air gaps, and massive silencers. So that might be one option: make this your CR, and have your LR elsewhere. I know you mentioned that the CR is not a high priority for you, that you need the LR much more urgently, but when the time comes, this area is a possibility.

You also have another option you might not have considered. More expensive, but probably do-able if you REALLY need that room down there: Instead of trying to make your ceiling higher, make your floor lower! In simple terms: dig! It might be possible to cut out the slab in that area, dig down a foot or so, and lay a new slab, lower down. There's a couple of forum members who have done that, with good results. It sounds scary, but it's not THAT bad. Worth considering.

- Stuart -