John Sayers' Recording Studio Design Forum Archive

Finally not living in a rental and have a house of my own to do what I want!

My goal is to have a room that's nice to mix and track in. I wont be doing live drums in the room and I track guitars direct. Isolation isn't a totally big deal for me, I am not tearing out all the drywall to insulate and decouple or anything like that, I just want a room that I enjoying spending a ton of time in. I'm never to loud in this room though if I am it can be hard to enjoy watching tv in the living room. Also my band practices with our entire setup in one of the upstairs bedrooms and the neighbors have never even complained about that, we play progressive metal. I'm DIYing anything I need because I enjoy building things and saving money.

As soon as we moved in, I selected room that was open to the main living room. It's 12 feet wide, 17 feet in length, and 8 foot ceilings. I framed the front wall that was open to the living room, and closed it up with 1/2" ply wood, and the wall in the living room was then cover with a layer of 3/4" ship lap.

Then I ripped out all of the carpet, to find the lovely previous owner, investor, did not care for the concrete floor to get covered in paint and wall texture. I love concrete floors so I am either going to rent a grinder to smooth them out and polish them, but may need to skim coat a layer of self leveling concrete over the floors first, they aren't completely flat and are actually pretty rough right now. I want to spend as little as possible, its a floor, so depending on cost I may just install some cheap vinyl plank flooring if the concrete is going to cost more. I already picked some out and the room would run me about $350, but I may be able to do the polished concrete for less.

LET THERE BE LIGHT!!

There was also ZERO lighting in this room, but a light switch that was linked to one of the outlets. I installed track lighting and surface mounted conduit to run the wiring, I love the industrial look and it was easy for me to do by myself.

The other side of the room is open to the entry way, as well, not having a door on your mixing room can be annoying, because there is literally no isolation from what ever I'm doing in this room. Yesterday I picked up an pre hung interior door so that I can keep the dogs out now that I'm actually putting my room together. I was going to frame it out today, BUT, it would be a pain to get my desk/small couch in and out for when I do the floors, so I am holding off as I plan to start the flooring tomorrow, and work on it this week. I can easily slide everything out of my studio into the dining room and get the floors done, paint, etc. before moving things back in and THEN putting the door in.

The portion of the front wall that I closed is still exposed to the studs, so I'm planning to rip out the rest of the drywall around the opening so that the entire front wall is exposed to the studs. Now I don't need to sound proof this room, but I'm thinking with the front wall already exposed I can insulate and drywall it so that watching tv in the living room is possible if I'm writing a song for 8 hours straight. I was thinking about treating that front wall as an inside out wall and using roxul, covering the front wall in a fabric but I just don't think that's what my room needs. So if I'm correct, I have no idea what I should get to insulate the front wall with before installing drywall over it.

I know I'm going to get input on this stuff but I'll proceed with my main questions for layout and design.

So at this point my floors will be done, lighting installed, room is closed and has a door, fresh coat of paint, and now I have a blank canvas of 204 sq ft to "treat". In the pictures you can see the existing panels that I have. A total of 6 - 4 feetx4feetx2inch thick 703. Planning to treat initial reflection points with these - 2 on front wall and 1 on either side of mixing position, as they currently are, and I was thinking to use the other two above as a cloud, not just directly above the listening position but above the speakers, with an angle as well. So side closest to the front wall would be a foot or so away from the ceiling compared to the other side being closer to the ceiling. I had read a post regarding the angle of cloud placement but can't seem to find it again.

So to touch on the listening position, I have spent endless hours on here and had originally planned to build a RFZ, soffit mounting my monitors, and doing an angled slot resonator on either side, and I would still love to do this, but would have to happen later next year. Then Barefoot released their footprint01s and that made me want to not build out the soffits because I'll be getting those in about 6 months. Right now I am mixing on yamaha hs8s and avantone mixcubes. With my current set up, I feel like I have some phase issues in the low end since the speakers are a few feet away from the front wall. These are obviously rear ported, so want to get them further away from me, put them on some stands I can build, and get them as close to the front wall as I can. I would also take my monitor shelf off of my desk, as it's really to high for my monitors and even my screen. I actually prefer mixing on monitors that are not so "near" to me, so I want/need to create that sweet spot for what I am currently using.

If I am correct about the front wall, what should i insulate it with and what thickness of drywall (if drywall) should I use to close it up?
What position and degree of angle should I place the cloud in?
What should my monitor placement be in my room? Putting the Hs8s on some stands and putting them as close to the front wall as possible, how far apart can/should they be?

My budget was to spend $700 on getting this room "together" to be able to let clients come over and get more projects moving, and then once this is complete I'll be willing to follow a plan on furthering my room treatment before any gear upgrades come.

Looking forward to responses.

Super excited on the progress I get to make in the next few days!

I'm going back and reading through a lot of my favorite threads on here and just wanted to drop in and leave these things here for other people who may have a similar situation and haven't spent as much time on here. Regarding the speaker placement, Stuart had typed up this rough guide, so thank you!

"So, a few "rules" and guidelines, in no specific order:

1) The speakers should not go in the corner, nor on the line that divides the corner. In other words, if your walls intersect at 90°, then draw a line out from each corner at 45°, and stay away from that: don't put your speaker exactly on that line, since it implies that you'll be getting the same artifacts from the side walls as from the front wall. Put your speakers either outside or inside of those lines. More commonly you'll want your speakers "inside" those lines (more towards the center line of the room).

2) The "38% of room depth rule" is not a rule, but it is a useful guideline for a starting point. You'll generally want to have your listening position a bit closer to the front wall than that location, but do be aware that you might be getting into problematic SBIR territory there. (You can treat that, to a certain extent).

3) Keep the mix position away from 25% and 50% of room depth, and try to stay between about 32% and 44%

4) You can angle your speakers differently than the "textbook" 30° angle: Anything in the range 25° to about 35° will work well under most circumstances.

5) Keep the speakers as far apart as possible, wile not violating rules 1 and 4.

6) Keep the mix position at a good distance from the speakers, within the range of about 1m to about 5m. Further away is usually better.

7) Don't put the speakers at 25% of the room width: that's a modal null for some frequencies, and a peak for others. Try something more like 28% to 34%.

8 ) Make the front baffle of your soffit as wide and tall as you can, within reason. The width should be at least three times the diameter of your low frequency driver. In other words, if you have a speaker with an 8" woofer, then you want the soffit baffle to be at least 24" (60cm) wide. Wider is better.

9) Do not put your speaker in the middle of the soffit baffle: Offset in both directions. In other words, the distances from the acoustic center of the speaker to each edge of the baffle should be very different, by at least 20%. So for example if your speaker axis is 30cm from one side of the baffle, it should be more than 36cm from the other side, less than 24cm from the bottom edge, and more than 44cm from the top edge. (Rough distances, for illustration only...). Larger differences are generally better.

10) Make the baffle as massively heavy as you can, and as rigid as you can.

11) Make the structure inside the soffit (the framing that holds the baffle and speaker in place) as rigid and massive as you can.

12) Mount the speaker inside an enclosure box that is either a very tight fit, in order to keep the speaker rigidly fixed in place, or mount it on suitable rubber pads, to completely decouple it from the the box. Carefully choose the properties and dimensions of that rubber, to make sure the speaker is still decoupled down to at least one octave below the speaker's low cut-off frequency.

13) Take into account that speakers need a lot of space behind them for cooling, and a path through the soffit for cooling air to flow.

14) Rear-ported speakers need special attention: Do not overload the rear port, acoustically, with an enclosure box that is too small, or un-ventilated, or un-damped.

15) Damp the hell out of the soffit interior! Fill it entirely with suitable damping if you want, except for the cooling path.

There's more to it than that, but it's a start!"

Now I wasn't going to soffit these right now, but I am going to get my speakers off my desk and up against the front wall on some stands. I don't believe I can afford to damp the soffit interior at this time, BUT getting the speaker stands and setting up the placement I imagine will remain the same. So think of this as the "pre-soffit" stage. I could easily build a super rigid frame and baffle around this speaker placement on the stand, that way the speaker is completely separated from the baffle itself, on a nice and heavy stand. Once they are in place I can order what I need to take the proper room measurements for you guys.

I like Johns modular design he posted that can be scaled to any room, not sure if I would need to have a modular design though, but I kind of want to use it as a baseline for my room design.

Would I not want to build the rigid frame out and install the baffle until I can damp the interior of the soffit correct?
I still want to damp the inside with something dense like roxul or 703?

but I am going to get my speakers off my desk and up against the front wall on some stands.

That's a great start! But you will also need some 4" OC-703 between the rear of the speakers and the front wall. The reason is simple: Placing the speakers against the front wall forces the SBIR issues up into the lower mid range, where they can be treated. If the speaker is too far from the front wall (but not far enough!), then the SBIR issues will be in the lows, where they are are very hard to treat. So force them into the "treatable" zone, then treat them.

I wasn't going to soffit these right now, ... I don't believe I can afford to damp the soffit interior at this time

Now I'm confused! If you don't build a soffit, then how could you possible put damping inside it???? If there's nothing there, then it's impossible to damp....

BUT getting the speaker stands and setting up the placement I imagine will remain the same.

Close, but not exact.

I could easily build a super rigid frame and baffle around this speaker placement on the stand,

That would be the frame of the soffit, but without the baffle, it isn't a soffit. It's just a frame.

Once they are in place I can order what I need to take the proper room measurements for you guys

You can find that here: http://www.johnlsayers.com/phpBB2/viewt ... =3&t=21122 .

Would I not want to build the rigid frame out and install the baffle until I can damp the interior of the soffit correct?

Once again: How can you put damping inside it, if you didn't build it yet? That's like saying "I'm going to take my friends for a ride in my car right now", but you don't yet have a car....

I still want to damp the inside with something dense like roxul or 703

When you actually build it, yes, you do want to damp it, and 703 would be fine, but NOT something denser than that. The problems inside the soffit will be low frequencies, so you certainly don't want dense insulation! You need light weight insulation. Dense would not do the job.


- Stuart -

That's a great start! But you will also need some 4" OC-703 between the rear of the speakers and the front wall. The reason is simple: Placing the speakers against the front wall forces the SBIR issues up into the lower mid range, where they can be treated. If the speaker is too far from the front wall (but not far enough!), then the SBIR issues will be in the lows, where they are are very hard to treat. So force them into the "treatable" zone, then treat them.

Alright, questions here if I'm not building the soffits now. How big does the 4" thick panel need to be and would it be centered behind the speaker? Do I mounted it to the front wall or do I leave a gap of air? Can/should the panel be angled into the corner?

Now I'm confused! If you don't build a soffit, then how could you possible put damping inside it???? If there's nothing there, then it's impossible to damp....

I've never built a soffit before, but I want to! I am under the impression that I would need a TON of 703 if I was going to build the soffits. So let me ask you, do you think I should just build the soffits and go for it completely? Is there a bare minimum of dampening I can start off with based on budget? i.e. Would it be 4" OC-703 floor to ceiling against the wall? I'd actually rather not upgrade my monitors if I could afford to properly build these now. (The barefoots cannot be flush mounted, so if I decide against flush mounting my current monitors, then I will focus on building out the panels and traps needed for a non soffit design.)

Close, but not exact.

So if I get things setup with the stands, I would NOT want to build the soffit around this speaker placement?

That would be the frame of the soffit, but without the baffle, it isn't a soffit. It's just a frame.

So if I add the baffle to the frame, it's now a soffit, but I would want to dampen it first right? Is there an option to not dampen it right away and open it up (unscrew the baffle) when I want to add dampening? Or maybe if I started out with some but wanted to add more?

You can find that here: http://www.johnlsayers.com/phpBB2/viewt ... =3&t=21122 .

Thank you!

Once again: How can you put damping inside it, if you didn't build it yet? That's like saying "I'm going to take my friends for a ride in my car right now", but you don't yet have a car....

I am talking about building it though! My concern falls within how much 703 or roxul I need based on what I can afford to do.

When you actually build it, yes, you do want to damp it, and 703 would be fine, but NOT something denser than that. The problems inside the soffit will be low frequencies, so you certainly don't want dense insulation! You need light weight insulation. Dense would not do the job.

So really the question is - how much 703 do I need in the soffits? Can I use something even less dense than the 703?

I have the modular design that John made but I'm not completely sure are where the insulation goes, and how much of it is needed for soffits. OC-703 (or any rigid fiberglass for that matter) is not stocked locally anywhere here and the shipping on this stuff literally eats my money. Not sure if there's an alternative you would recommend that I can buy locally, even if I have to use more of it, just for dampening of soffits that is.

How big does the 4" thick panel need to be

One full panel should be more than enough. Ideal would be to cover about three times the width of the speaker and twice the height, but twice the width and twice the height would be OK.

would it be centered behind the speaker?

Yes, roughly.

Do I mounted it to the front wall

Yes

do I leave a gap of air

No, because that implies that the speaker is further away from the wall than it should be. Don't forget that the number one problem you are dealing with here, is the SBIR associated with the front wall. The frequency where the fundamental SBIR dip occurs plays a large part in defining the overall signature of the room. The lower that frequency is, the worse it is for the room, and the harder it is to treat. There's a very simple relationship here: the frequency where that lowest dip occurs, is directly related to the distance between the speaker and the front wall. It's the front wall that causes the dip. If the speaker is far away from the wall, the dip forms at a low frequency, which cannot be treated with simple absorption. As the speaker gets closer to the front wall, the frequency of that lowest dip rises to a point where it can be treated with absorption, if it is thick enough. The highest frequency is when the speaker is right up against the wall, with nothing in between, but that means you can't absorb the SBIR problem, because there's no space to put the absorption in there! So that 4" space is what you need: it allows you to put in 4" of 703, which does a reasonable job of treating the SBIR. It would be nice to have a larger gap, filled with more 703, but that would push the frequency down lower again.... In other words, 4" is roughly optimal. Less that that and there's not enough treatment to be effective, ... more than that, and the frequency is too low to be treated...

Can/should the panel be angled into the corner?

You are confusing bass trapping with SBIR treatment. Yes, you ALSO need thick, large, deep, tall treatment in the corners of the room, but that has nothing at all to do with SBIR and the front wall, nor is it related to the reasons why you should soffit mount your speakers. Two different things. The treatment between the speaker and the front wall is purely about SBIR and related issues. The absorption in the corners is purely bass trapping.

It's important to know WHY you are doing certain things in your room, rather than to just do them blindly because someone told you on the internet, or because you saw it in a book...

I am under the impression that I would need a TON of 703 if I was going to build the soffits.

I think you are confusing soffits with bass trapping again! You need a ton if absorption for bass traps, yes, and the scrap bits of insulation that are left over after you do that can be used to dap the soffit interior...

The purpose of the insulation inside the soffit, around the speaker box, is the same as the purpose of the insulation inside the speaker cabinet itself: if you have ever looked inside a speaker cabinet, you'll see some insulation around the drivers, in the cavity. Same principle inside the sofft: it damps internal resonances that would be going on otherwise, due to the walls of the cabinet (walls of the soffit). That's all. So just throw in all your left-over scarp pieces of insulation, filling up the interior of the soffit as much as you can, and taking care to NOT block the air ventilation path up the back of the speaker.

do you think I should just build the soffits and go for it completely?

If you have the carpentry skills, and the money to do that, then sure! Soffits are the best single thing you can do to your room to make it great.

Is there a bare minimum of dampening I can start off with based on budget? i.e. Would it be 4" OC-703 floor to ceiling against the wall?

Once again, you are confusing problems and solutions here! The insulation against the front wall is NOT equivalent to the insulation in side the soffit! Those are two entirely different problems, and two entirely different solutions (that happen to use the same material). The 703 against the front wall is to deal with SBIR mostly, not to damp resonances inside a box. If you soffit mount your speakers, then there IS no SBIR associated with the front wall! It's gone. Not there. Impossible.So it does not need treating. However, by putting your speaker inside another box (the soffit), then you have created a set of resonances that did not exist before, so you now you need to damp those. It turns out that 703 is pretty good for that job as well, but it's a very different job. Different problem. Different solution. It's important not to confuse the problems you are dealing with in each situation. It's important to understand what is going on in every single case, so you can treat each individual problem suitably.

The barefoots cannot be flush mounted

Right. That specific model of speaker is one of the very few that cannot be soffit mounted, due to the side-firing woofer. If you do want to soffit mount your speakers, then you'd need to choose other speakers that can be soffit mounted.

So if I get things setup with the stands, I would NOT want to build the soffit around this speaker placement

Correct. Because the framing you need to build to create the soffit, and the internal structure, force you to move the speaker away from the wall and change its position. It would not be possible to set up your speakers in the perfect non-soffited location then just build a soffit around them, and you would not want to do that anyway. When you start designing your soffits and tweaking the structures, positions and angles, you'll see why.

So if I add the baffle to the frame, it's now a soffit,

Weeelllll...... only if the entire thing was designed that way!

but I would want to dampen it first right?

Once again: Why? And how? If you did not build the soffit, then there is no "box" to resonate, hence no need for damping. How can you damp a box that does not yet exist? You can't treat a problem that you don't have. You only have a resonant box if build a resonant box! If there is no box yet, then there is nothing that needs damping, and indeed just hanging the insulation around without the box would probably take out too much of the high end response from the room.

Is there an option to not dampen it right away and open it up (unscrew the baffle) when I want to add dampening?

Well you could do that, yes, but I can't see why you would want to! The box would be resonant as soon as you built it, and with no damping in there, the resonances would ring, loud and clear. Plus, the cost of the insulation to put inside the soffit is only a tiny fraction of the cost to actually build the soffit, so I don't see any reason for NOT wanting to damp the soffit, at the same time you build it.

So really the question is - how much 703 do I need in the soffits?

Ideally, you fill the cavity between the actual speaker cabinet plus it's surrounding enclosure, and the "box" that is the soffit itself, defined bu the front baffle, the shelf under the speaker, the front wall of the room, the panel on top of the soffit (or the ceiling, if there is no panel), and the side panels. It's not a large volume. Much less than you need for EACH of your bass traps. That's why I normally fill the soffits with the off-cuts that are left over after building the rest of the room, and all the rest of the treatment.

Can I use something even less dense than the 703?

Such as? What did you have in mind? Check the Gas Flow Resistivity numbers for the product you have in mind: as long as it's not much less than about 6,000 MKS rayls, that should be OK. And certainly not more than about 20,000 MKS rayls in the other direction.

I have the modular design that John made but I'm not completely sure are where the insulation goes,

It goes inside the "box" formed by the soffit panels, around the speaker, after it has been properly mounted. You might also need additional insulation for the hangers under the speaker shelf, and above the top panel. And of course you'll need a stack more for your bass traps.

OC-703 (or any rigid fiberglass for that matter) is not stocked locally anywhere here and the shipping on this stuff literally eats my money. Not sure if there's an alternative you would recommend that I can buy locally,

OC-703 is really good, but it's not the only product. Any type of porous insulation will work, to a greater or lesser degree. Pretty much type of fiberglass or mineral wool insulation will work, as long as the GFR is not too high or two low. Broad ideal range: roughly 9,000 to 18,000 MKS rayls. You can go a bit outside that on both ends and still get usable performance, but it starts tailing off outside that range.


- Stuart -

Making a ton of progress on on the room, I'll post some pictures after I get a top coat on the floor and am waiting for it to dry, about to make another run to the hardware store.

I decided I am not doing the soffits in this phase of my build. If I don't upgrade my monitors to a pair that cannot be soffit mounted, I would like to build them based off of John's modular design.

What I've done so far:

Obviously I had to empty the room, after that I prepped the doorway so that dust wouldn't escape into the rest of my house. (Some how, dust still managed to get absolutely everywhere... lol)

I put 1 rough coat of black paint on my ceiling, it's extremely textured so it didn't cover completely very well and I didn't edge in just yet. My house was renovated before we bought it and for whatever reason they decided to "re-texture" the walls, and it came out horrible. It's un even and razor sharp basically. In other rooms I fixed it by sanding the entire walls down with 60 grit fairly quickly.

Next up, rented a diamond grinder for concrete floors. I spent about 6 hours wrestling a 150lb machine to grind down my terribly rough and uneven floors. THIS is where the dust came from, though it was hooked up to a shop vac to pick up most the dust, which it did, there was just so much.

The next day it took about 10 hours to clean up all of the dust. Vacuuming, blowing out with an air compressor, more vacuuming, moping 3 times, cleaning off the walls. Seriously, if you have smooth concrete that didn't need this work, you are so lucky... Now that there is little to no dust left on the ground it was time to etch it as part of the prep for the stain. This included vigorously scrubbing an acid compound on the floor, follow by...... you guessed it! MORE MOPPING! After that, I had to let it completely dry over night. In the morning, you can tell the concrete is more open, but also there was still some dust left over. I vacuumed again, with a brush attachment and voila, 0 dust to the touch. I used 2 different colors of concrete dye, spayed on with a pump sprayer, and I have to say, it looks freaking awesome!

Today I am sealing the floor with the sealer, and I will be doing 2-4 coats. Also building my speaker stands that have been discussed on the forums here while in-between coats. Tomorrow when it drys, I will be masking off the floor ( have to paint the base boards... ) and finish painting the ceiling, which makes some of the rough texture fall off, so less mess if I put some tarp down. Painting all except the front walls white. While that's drying, I want to work on the front wall.

I was originally going to insulate the front wall and then sheet rock over it, but now I'm thinking about insulating the front wall with roxul safe n sound, and doing a fabric cover on the entire front wall, floor to ceiling. I found this comparison and know I've seen lots of people make panels out of this stuff, trying to find the GFR of it.

Product-thickness-density-125hz-250hz-500hz-1khz - 2khz - 4khz - NRC
703 - 3" (76mm) - 3.0 pcf - 0.53 - 1.19 - 1.21 - 1.08 - 1.01 - 1.04 - 1.10
S‘n’S 3" (75mm) - 2.5 pcf - 0.52 - 0.96 - 1.18 - 1.07 - 1.05 - 1.05 - 1.05

If this is not a bad idea, would I want to do a layer of plastic over it before the actual fabric? I will still hang my 4 foot x 4 foot 703 panels behind the speakers as well, so that would mean I'd have around 5 inches of absorption on the front wall behind the speakers, and 3 inches where my panels are not, thought its not as dense as 703.

I'll post pictures as soon as I get a break, and I REALLY appreciate the feedback and look forward to more of it.