New home studio project in Texas

Greetings from San Antonio, Texas! Been following this forum for several months and absorbing as much information as possible. It's like drinking from a fire hose! I'm in the early phases of designing a freestanding outbuilding in our backyard, which will serve double duty as a home office and project studio. (That's a fancy way of saying "man cave". 8) ) I am a composer, singer and instrumentalist so I will use this studio to record and mix my own compositions on a Mac using Apple Logic Pro X. My set up is lean and mean: A pair of Neumann KH 120 near field monitors, MOTU 828 interface, assorted mics, a USB controller, a fast MacBook Pro and a comfy chair. I have a number of keyboards, guitars and amps which will be cranked up during recording sessions, but since I play all parts individually Lenny Kravitz-style, I won't be generating full-on garage band noise levels. Drums are typically sampled so no real concerns about having to deal with the crushing levels of a full live kit. The style of music I create is hard rock and pop in the vein of Muse, Radiohead and Depeche Mode. The primary reason for this post is to seek some suggestions from the pros regarding optimal layout and design for the studio space as well as proper techniques for sound proofing BEFORE we launch into construction. Okay, I'm all about playing by the rules of the forum, so here are the details of the project: Total budget for this project: Not to exceed $70,000 USD Noise Isolation Studio will be in the backyard of our home, which is in a typical American suburban setting with single-family homes in all directions. Nearest neighbor’s house is 50 feet away. Our main home and master bedroom will be only 25 feet away. Our property backs up to a wooded greenbelt, which affords us some great isolation from other homes. My primary concern is to not annoy the neighbors or my family when I’m in the studio at night. At 1 AM, I don't want them to hear me belting a vocal lead into a mic, working out an amplified guitar solo with distortion, or listening to the same 16 bars of a rock chorus 95 times in a row during a late night mixing session. Loudest sessions could spike up to 95dB. Ideally, with some basic isolation techniques in place, I’d get the sound levels to the 50-60dB range or quieter. Outbuilding Specs The building is new construction on a concrete foundation. Footprint is 22’ x 16’ with the actual studio being 14’ x 15’-3”. Exterior: Brick and Hardi-Plank over Tyvek wrap and 7/16 oriented strand board (OSB) Exterior walls: 2 x 6 wood framing Interior walls: 2 x 4 wood framing Ceiling: 2 x 6 wood joists and rafters Floor: Stained concrete Ceiling height: 9’ plate with scissor truss to create an angled, raised ceiling in studio So here are my specific questions: Exterior Walls We're using a mass-spring-mass model with all walls and ceilings. My GC is telling me that he'll use 6" studs for all exterior walls in order to provide a wider air barrier and allow us to blow in more R19 insulation. The outer leaf of the exterior walls is brick up to the wainscot and Hardi-Plank to the roof. All masonry will be installed over OSB wrapped in Tyvek. Inner leaf will be "Soundrock" mounted directly to the wood studs. The ceiling and interior walls will be insulated with batting rated at R30. How do you recommend adjusting this initial strategy to hit our decibel reduction goal? HVAC Would you recommend putting a mini split in this studio vs. a conventional duct system with the furnace and air handler located above bathroom area? And if mini-split is the way to go, where would you put the wall unit? Cabling For recording sessions, I will often have several mics, an electric acoustic, electric guitar, bass, and keyboards all powered up at the same time. With such a small space, I need to minimize cables running all over the floor. I’d like to run cable in the walls for headphone returns, XLR, balanced/unbalanced ¼” jacks, MIDI, CAT 5, video and power. What are your recommendations for electrical wiring and cabling in this space? Number of cables per conduit? Location of the wall box(es)? Best materials to use? Monitor Placement Given the geometry of the room, what is the optimal position (angle, height, distance between speakers) for the monitors? I have a 27” cinema display that sits between the speakers, along with my Mac, so I’m considering mounting a flat screen TV on the wall to replace the cinema display and get out of the way of the KH 120s. But I could also wall mount the 120s if that provides advantages. Thoughts? Sound Management Again, given the room dimensions, I would appreciate some pointers on how to handle reflection points. Slot wall resonators or diffusers? Bass traps? Door and Windows During the day, I’m like a plant—I crave sun. The main entrance will be the primary source of natural light. From a practicality standpoint, I also want the main door wide enough to accommodate large furniture or gear, like oversized keyboards, amps and such. I also realize that the door (and windows) are going to be the primary sources of sound leakage, so I’m thinking of putting in a soundproof glass sliding door like this: http://www.soundproofwindows.com/doors.html Windows are currently spec’d at 2’ x 2’ aluminum cased, double paned sound studio windows. They hang at the 8’ header mark to allow me to use the wall below them for furniture and perhaps a wall mounted flat screen TV to replace my desktop cinema display as the main monitor. Am I on the right track with door and windows? Lighting We’re putting in a scissor truss to raise the ceiling at a 30-degree angle to an 11’ – 5” peak centered on the room (see dashed line on floorplan). As far as lighting the space, would you recommend using recessed cans or another type of ceiling mounted light fixture? Thank you kindly for your time and input! It is tremendously appreciated.

Hi there "johnnynav", and welcome to the forum!

It's like drinking from a fire hose!

I know the feeling! And if you've only been reading for a couple of months, just wait until we turn the fire hose on toe "high" setting.... :)

I'm in the early phases of designing a freestanding outbuilding in our backyard,

That's great, since you aren't limited by an existing building: you can build it any shape or size you need.

Total budget for this project: Not to exceed $70,000 USD

Sounds reasonable. Your total footprint is about 350 ft2, so you have about US$ 200/ft, which is very good. You are probably one of the few people to come on the forum with a totally decent budget! Normally you see comments here along the lines "You'll need to increase that", but in your case you should be good.

My primary concern is to not annoy the neighbors or my family when I’m in the studio at night.

OK, but have you also considered noise coming the other way? Wind, rain, hail, thunder, aircraft /helicopters flying overhead, traffic on nearby roads, railway lines, cars arriving/leaving, noise from the house: vacuum cleaner, TV, phone, radio, people talking, lawnmower, etc. There's an awful lot of stuff outside that can ruin your perfect take of a difficult vocal...

Loudest sessions could spike up to 95dB. Ideally, with some basic isolation techniques in place, I’d get the sound levels to the 50-60dB range or quieter.

You can pretty much do that with an ordinary wall: a 2x4 stud frame with a single layer of drywall on each side and insulation in the cavity will get you about "30-and-a-bit" dB of isolation. That would knock your 90 down to under 60. But I'm betting that this isn't really enough, and you probably need to get it down a bit lower than that to be comfortable, going both ways (in and out). 60 dB is normal conversation level, so if you are belting out your perfect vocal track at 90 dB inside, with 30 dB of isolation, that sounds like normal talking level outside your walls. Probably more than you wanted. I'd suggest aiming for at least 40 dB of isolation, which is very easily do-able with your plan and budget.

Outbuilding Specs

Hmmm, I see floor, outer wall, inner wall, and ceiling, but I don't see the roof...?

My GC is telling me that he'll use 6" studs for all exterior walls in order to provide a wider air barrier

You don't need bigger studs to do that! You just need more space. Meaning that you set your inner-leaf framing a few inches further away from your outer leaf frame, but both frames can be 2x4 (unless you need them to carry some huge load).

and allow us to blow in more R19 insulation.

I wouldn't use blown-in insulation: Unless it is done very carefully, it can pile up in some places, creating flanking paths, and leave unnoticed voids in other places. Both of which are harmful to your isolation. Ordinary batts are the way to go.

The outer leaf of the exterior walls

Hang on a sec! There might be a conceptual issue here. The exterior wall does not have an "outer leaf" and an "inner leaf": the exterior wall IS the outer leaf. Your exterior wall consists of one single leaf, and that is all. Then your interior wall also consists of one single leaf. That's how you get a 2-leaf MSM system.

How do you recommend adjusting this initial strategy to hit our decibel reduction goal?

I would say you are already there, but I'm confused: If your outer leaf is brick, then why is there also a 2x6 frame for it? A proper brick wall stands up by itself, and needs no frame. Maybe you are talking about some form of brick veneer? If you really are doing your outer leaf as a true brick wall, then there is no need for any frame. The inner-leaf needs a frame, yes, but if the outer leaf is brick, then no frame required.

HVAC Would you recommend putting a mini split in this studio vs. a conventional duct system with the furnace and air handler located above bathroom area? And if mini-split is the way to go, where would you put the wall unit?

It's basically a single-room studio, so a mini-split is fine. I would put it on the rear wall, up high, close to the ceiling. But a mini.split is only part of "HVAC". You still need the "V" part, which is "ventilation". A mini-split only cools and dehumidifies (some also heat), but does not bring in fresh air, nor exhaust stale air to the outside. For a normal house, that isn't an issue, but studios need to be sealed air-tight to get the isolation, so you do need to have some sort of simple duct system to get air in/out. Just a couple of ducts with a fan at some point, and silencer boxes where the duct goes through the wall. You could probably do all of that in the attic space.

Cabling For recording sessions, I will often have several mics, an electric acoustic, electric guitar, bass, and keyboards all powered up at the same time. With such a small space, I need to minimize cables running all over the floor. I’d like to run cable in the walls for headphone returns, XLR, balanced/unbalanced ¼” jacks, MIDI, CAT 5, video and power. What are your recommendations for electrical wiring and cabling in this space? Number of cables per conduit? Location of the wall box(es)? Best materials to use?

Keep your electric cables and signal cables very far apart. The common way of doing that in studios is to run all electrical stuff at the top of the walls, and all signal stuff at the bottom. Then drop down verticals from the wall top to get to switches, outlets, light fittings, etc. If the electrical and signal cables do have to cross at some point, then do so ONLY at an angle of 90°. They should NEVER run parallel and close together. If that were my room, I would use snakes for the signal cabling: put a couple of stage boxes on the rear wall, a couple on the side walls, and run everything to a patch bay at your desk. Simple, elegant, effective.

Monitor Placement Given the geometry of the room, what is the optimal position (angle, height, distance between speakers) for the monitors?

There's a pretty much "standard" layout for that, as defined by the ITU, EBU, AES and other organizations. They all have slightly different things, but very close. Basically, your speakers should be set up such that the acoustic axis of the speaker is 1.2m above the floor (about 47-1/4"). The speakers and your head make up a triangle, so the distance between the speakers is about the same as the distance from each speaker to your head. The speakers should be "toed in" at an angle of 30°, such that they are aimed at a position about a foot or so behind your head, and your head should be about 38% back from the front wall (38% the distance from front wall to back wall). Not that all of these refer to the acoustic axis of the speaker, not the top or bottom of the cabinet, and not the center of the woofer or tweeter. K&H has a document on their web site that identifies exactly where the acoustic axis is for each of their speakers. I'm designing a studio right now that uses K&H, so I have that document somewhere, if you can't find it. Let me know if you need it. There's more to it than that, of course (nothing about acoustics is as simple as it looks ! :), but that's the basic idea.

But I could also wall mount the 120s if that provides advantages.

Oh yes, totally, absolutely and unreservedly YES! Flush-mounting your speakers in the front walls (often also called "soffit mounting") is about the single best thing you can do to improve the acoustics of the studio, and your K&H 120s can indeed be soffit mounted. If you have speakers on stands, then the sound leaving he speaker interacts with itself as it bounces around off the front and side walls, the ceiling, etc. That causes "coloration" of the sound, comb-filtering, phase cancellation, SBIF, edge diffraction, and several other nasties. But if you flush-mount your speakers, all of that goes away: it just isn't there any more, because acoustically speaking the speakers are not in the room any more! So that would be my number one recommendation: flush-mount ("sofffit mount") your speakers. The K&H are great speakers, and they can really benefit from this. Your room is also a nice size, and can also benefit.

Sound Management Again, given the room dimensions, I would appreciate some pointers on how to handle reflection points. Slot wall resonators or diffusers? Bass traps?

That depends a bit on your design concept, but if you do go with flush-mounting then the obvious choice is RFZ design for your room, which basically means that the room is shaped geometrically so that no first-order reflections get to your ears: only pure, clean direct sound from your speakers. In that case, you treat the room so that all the reflections arriving at your ears are second or third order, and arrive at your ears later than 20ms after the direct sound, and 20 dB down, and are diffuse, not specular. There are ways of doing that, but it's a bit complex to go into right now. We can get to that later, if you decide to go the RFZ + flush-mount path. If not, then you will need treatment on your first reflection points (thick absorption) as well as between the speakers and the front wall, and across the rear wall. In either case you will need a lot of bass trapping, since it is a small room: typical candidates for that are the vertical room corners at front and rear, and Superhcunk style bass traps are really good for that. Very effective. Another possibility is hangers.

From a practicality standpoint, I also want the main door wide enough to accommodate large furniture or gear, like oversized keyboards, amps and such. I also realize that the door (and windows) are going to be the primary sources of sound leakage, so I’m thinking of putting in a soundproof glass sliding door like this:

Right: Sliding glass doors are great for light, etc., but in reality the actual opening is about the same size as a typical hinged door: only one side of the slider opens! Sliders are normally 6' wide, meaning that you get less than 3' of actual clear opening for a 6'. Some sliders are 8' wide, which does give you a bigger opening, but at a price.... both in terms of money (those things aren't cheap!) and in terms of acoustics: that's well over 8' of wall that is totally reflective and cannot have any acoustic treatment at all on it. Also, there's the issue that you don't just need ONE of those doors: you need TWO of them, back to back, with an air gap between them. One goes in your outer-leaf, the other in your inner-leaf. Also, beware when you see a manufacturer making claims like "Noise reductions beyond 75%". That sounds like a lot, but is actually not much at all. In fact, it is only 6 dB! :shock: Yup, do the math. The equation is 10 log x/y, where "x" is the measured level, and "y" is the reference level. So if it went down from the reference level of 100 to the measured level of 25 (a 75% reduction), that is simply 10 log 0.25 = -6.02 dB. So a reduction of 75% in sound intensity is exactly the same as a reduction of 6 decibels... I would seriously hope that your doors are waaaay better than 6 dB! When you see sound reduction expressed as percentage in claims about acoustic products, proceed very carefully... those numbers are meant to sound good in marketing hype, but turn them into useful acoustic numbers, and they don't mean much. "Our product reduces sound by 90%!!!!". Amazing. Not. 90% reduction is only 10 dB.... "Ours does 99% reduction in sound power!!!!" yippee. wonderful... Not. That's only 20 dB. I would hope that the doors you choose can get you at least 40 dB of isolation., and hopefully even more.

Windows are currently spec’d at 2’ x 2’ aluminum cased, double paned sound studio windows.

Whoa! Are you sure about that? "double pane" and "single frame" don't really go together with "studio window". Normally studio windows are built up from two separate panes of glass, each in its own frame, one frame in each leaf. Just like your walls, ceiling, and doors, you need one pane in your outer leaf, and the other in the inner leaf, with no mechanical connect between them.

Lighting We’re putting in a scissor truss to raise the ceiling at a 30-degree angle to an 11’ – 5” peak centered on the room (see dashed line on floorplan). As far as lighting the space, would you recommend using recessed cans or another type of ceiling mounted light fixture?

That's really hard to say, since you didn't mention anything about your isolation plan for the ceiling, and you didn't mention anything about the roof! Once again, what goes above you is done the same as what goes around you: there is an outer leaf (the roof), and an inner leaf (the ceiling), and they are on separate frames, not attached to each other at all. It would help if you could do your basic design in SketchUp, which is 3D software, rather than in flat 2D drawings. Sound moves in 3D, so it's necessary to have your model in 3D, to better understand how the sound interacts with the room... Hope that helps a bit! - Stuart -