952 Studios Design Planning

[Soundman2020]

once you account for the 2x6 outer wall, the 1" air gap, and the 2x4 inner wall, I lose 100ft2 of space. So really, I only have about 400ft2 to work with.

... unless you do the inner walls "inside out"...

With inside-out walls and ceiling, you don't loose the width of the inner-leaf studs and joists: that air volume is still inside the room. You lose a lot less space like that. Yet another trick that can be used to save space in small studios.

- Stuart -

[eightamrock]

once you account for the 2x6 outer wall, the 1" air gap, and the 2x4 inner wall, I lose 100ft2 of space. So really, I only have about 400ft2 to work with.

... unless you do the inner walls "inside out"...

With inside-out walls and ceiling, you don't loose the width of the inner-leaf studs and joists: that air volume is still inside the room. You lose a lot less space like that. Yet another trick that can be used to save space in small studios.

- Stuart -

That’s a good idea, but how does it impact isolation? Reducing the air gap reduces the ability to trap the sound, no?

[Soundman2020]

Source of the post That’s a good idea, but how does it impact isolation? Reducing the air gap reduces the ability to trap the sound, no?

With 2x6 outer-leaf studs plus a 1" gap to the inner-leaf, you have 6 1/2" cavity depth. With sufficient mass on both leaves, that can still get you substantial isolation. The equation for 2-leaf MSM resonance depends on three factors, mainly: The mass on each leaf, the cavity depth, and the insulation fill in the cavity. You can compensate for lack in one of those by changing the others. So if you reduce your cavity depth, you can increase the mass to compensate.

If you want to gain even more space (squeezing out every last square inch), then you can user "thinner but higher density" material for your sheathing: For example, instead of using drywall, use fiber-cement board, which has about twice the density, so you can use half the thickness. Do that on both leaves, and you gain even more.

But it is important to do the math and make sure your MSM resonance is low enough, and your isolation is high enough, for your goals.

- Stuart -

[eightamrock]

Source of the post

Source of the post That’s a good idea, but how does it impact isolation? Reducing the air gap reduces the ability to trap the sound, no?

With 2x6 outer-leaf studs plus a 1" gap to the inner-leaf, you have 6 1/2" cavity depth. With sufficient mass on both leaves, that can still get you substantial isolation. The equation for 2-leaf MSM resonance depends on three factors, mainly: The mass on each leaf, the cavity depth, and the insulation fill in the cavity. You can compensate for lack in one of those by changing the others. So if you reduce your cavity depth, you can increase the mass to compensate.

If you want to gain even more space (squeezing out every last square inch), then you can user "thinner but higher density" material for your sheathing: For example, instead of using drywall, use fiber-cement board, which has about twice the density, so you can use half the thickness. Do that on both leaves, and you gain even more.

But it is important to do the math and make sure your MSM resonance is low enough, and your isolation is high enough, for your goals.

- Stuart -

I might actually have to do this in the live room. I spent the weekend playing around with the design trying to get the most out of it. I have 180ft2 in the live room and 200ft2 in the control. If I do the inside out walls in the LR I can gain another 12-15 sq ft. That gets me damn close. The LR will also have 12' vaulted ceilings, so I will have well over 1500ft3 of volume in the room.

Updated layout here. I was also able to move things around to make sure I had sizable allocation in the CR for bass traps.

[eightamrock]

Ok I have moved on to doing the control room planning, but I am already hitting a wall (both figuratively and literally)

A bit about my design. The sofit faces are 2' 9" wide. They are angled at 35 degrees. My listening position apex is about 6' from the wall (38%) of the room, and my ears are about 18" in front of that. I have positioned the chair about where I would be sitting in the room.

Following all the best design guidelines 25-35 degree sofit angles, 38% of room length for listening, and position the speaker neither on the 45 degree line from the corner of the room, nor at 25% of the room width, (Im at 20%). I am already having issue with first reflections hitting my listening position.

My options that I can see are:

A. go wider with the speakers and angle them even more, but that takes me closer to the 45 line from the corner of the room.
B. Go narrower with the speakers and soften the angle, but that gets me closer to the 25% of the room width mark which is bad.
C. Build the soffit faces wider to catch that first reflection and throw it somewhere else
D. Build absorbers and move the window
F. Give up and keep mixing in headphones.

Any advice on the above? Also, am I even approaching this correctly? Ive only done the first few ray traces and Im already seeing issues.....it is discouraging.

[eightamrock]

Here is some updated modeling. Moved the speakers wider, soffits now angled at 30 degrees. The first reflections off the side wall are now behind my head, but I am now getting some reflection from the rear wall that will be problematic. I suppose in this case I just treat the rear wall and I'm close to ok?

Still dont know if I am even approaching this the right way.

[eightamrock]

I guess I could build another bass trap in the middle and that might catch those rays?

[Starlight]

Here is the rear wall trap from Gareth's Garden mix room near Nottingham, UK. Gareth mentions the largest hanger is 64cm deep and 2m tall, that is over two feet deep.

Regarding your posts 21 and 22, I struggle to see from your plans how the rear wall traps will be anywhere near effective enough. If you don't need the windows I would remove them or block them off so that you can use the whole of the rear wall as a trap. If you need the windows then I would be looking at leaving them but covering every other square inch of the rear wall with a suitably deep trap.

[garethmetcalf]

Thanks for sharing my picture Starlight! It’s nice to know my thread can be of some help to others. In my case I intentionally picked where the windows and door would be to avoid reflections, rather than choosing their location first.

Gareth

[eightamrock]

Source of the post Regarding your posts 21 and 22, I struggle to see from your plans how the rear wall traps will be anywhere near effective enough. If you don't need the windows I would remove them or block them off so that you can use the whole of the rear wall as a trap. If you need the windows then I would be looking at leaving them but covering every other square inch of the rear wall with a suitably deep trap.

So based on this feedback I need something more like this. It would be 2' at the corners. I need to do the real math on the depth and density I'd need. Can I do that without actually testing the room fully stood up?

Source of the post Thanks for sharing my picture Starlight! It’s nice to know my thread can be of some help to others. In my case I intentionally picked where the windows and door would be to avoid reflections, rather than choosing their location first.

Yeah I have options to move things around because it is a new building. I took the windows out, can try to find another place for them.

[eightamrock]

I'll tell you what, the more I stare at my design, the more I dislike it. This process is exhausting!

I like where I have landed with the layout for the most part, though I still feel like I could free up floor space for the live room I just cant figure out how. Im wondering if I should give up the airlock and the iso booth, just have the bathroom entrance and the main entrance all through the live room. I'm just concerned of foot traffic (mostly my kids) interrupting sessions coming through... the airlock was a functional and practical add to the design...

[Soundman2020]

This process is exhausting!

Welcome to the world of studio design! It is, indeed, a tough job, and not easy to do. People think it's just a matter of "copy/pasting" a few standard bits into a rough outline, and you are done.... Nothing could be further from the truth. Good design takes time: Months, usually, from an empty page to a workable final design with good acoustics built in, along with good functionality and good aesthetics. It ain't easy!

My listening position apex is about 6' from the wall (38%) of the room, and my ears are about 18" in front of that.

You seem to have things a bit backwards! The theoretical 38% spot is where your EARS go, not where the triangle apex goes. The reason for that is because the 38% spot supposedly has the least-terrible modal response. If you figure out all the major modal issues for modes related to the front-back direction (including axial, tangential, and oblique modes associated with that dierection), superimpose them all on one another, then 38% is where the ugliness is least ugly. So that's where you want your ears: where the modal response is minimally bad.

In theory.

In practice, it's just a starting point. In real-life there are many other things that can affect the "best" spot, which is why I recommend using the "walking mic" process to help find that spot. The "walking mic" test, using REW ... and to help avoid unpleasant spots.

It is often the case that the "best" spot (or more correctly, the "least bad" spot) is a few inches in front of the 38% theoretical ideal... but not always. The most important point about the 38% rule, is that it is not a rule at all! It is a guideline, or a starting point.

Following all the best design guidelines 25-35 degree sofit angles, 38% of room length for listening, and position the speaker neither on the 45 degree line from the corner of the room, nor at 25% of the room width,

Those, too, are guidelines, not carved in stone. When I wrote that, I was of two minds of publishing it, or not, for the same reason Wes later regretted publishing his 38% rule: People see that, and think that they absolutely must follow the "rules" exactly, in order to get a perfect layout in the room. In reality, there is no "perfect" layout: Just a bunch of really bad ones, a few not-so-bad ones, and maybe one or two "acceptable" ones. That's part of what studio design is about: identifying the most acceptable spot in any given room, based on that room and that set of speakers, not necessarily a set of "rules" that might not be totally accurate for the room in question, or for the speakers actually used.

I'd encourage you to do the walking mic test, identify the good and bad spots, then do some critical listening in the room to confirm if that really is the case, then choose your listening position based on that.

If you want to get extra fancy, then once you have your listening position decided, then do the same thing with the speakers. I've been meaning to add a "walking speakers" test procedure to the forum, similar to "walking mic", as that can also help avoid trouble spots for speaker placement.

And if you really want to go "extreme overkill" on this, then, with the speakers in their new "optimal" position, repeat the walking mic test, to see if there might be an even better spot. Rinse. Repeat.

Of course, you have an empty room right now, so doing the above isn't easy to start with, and the conditions will change once there is treatment in the room, but this process can usually get you to a pretty decent arrangement of speaker locatio and mix position. Then you can adapt the speaker position to the soffit design, trying to keep a similar position and relationship.

Ive only done the first few ray traces and Im already seeing issues.....it is discouraging.

Your soffits have no "wings" on the outboard front faces. Right now, you have a sort of "reverse wing" that is just perpendicular to the wall, but proper wings can be adjusted to help with reflections.

Also, your window seems to extend too far forward, as it is catching the first reflections and preventing you from adding the soffit wing. I would move the window backwards a bit.

Another issue:; If you do insist on splaying the side walls of the room, then splay them at a greater angle and don't extend the splayed part so far back into the room. Your splayed wall end very far back in the room, and are not accomplishing anything useful like that. I'd still suggest just building the room as a rectangle, and adding soffit wings to accomplish the same purpose as splayed walls would, far more simply, cheaply, and with a greater chance of being able to predict modal response correctly.

but I am now getting some reflection from the rear wall that will be problematic.

Then your rear wall is badly designed! as Starlight and Gareth mentioned, your rear wall acoustic treatment needs very careful design to deal with those issues you are encountering, as well as with a whole series of other issues. The real wall of any control room is always the one that needs the most treatment, by far, and that treatment needs to be deep, wide, high, and properly tuned to deal with the problems. Rear walls should not be reflective at all, or if there are reflective surfaces back there, then the necessary precautions should be taken to minimize the problems, and absolutely to ensure that there are no specular reflections back to any listening position in the room.

One of the key design concepts for RFZ style rooms, is the "20-20" issue (hence, my screen name...). Your goal should be to ensure that there are no reflections at all arriving back at your ears within 20 ms of the direct sound, and the ones that do arrive should be -20 dB down in intensity. That 20 ms "initial time delay gap" followed by a smooth, even diffuse decay across the entire spectrum, and the overall decay time should then meet the criteria for critical listening rooms: you don't want it decaying too fast for the size of room, or the room will sound "dull" and "dead", and you don't want it decaying too slowly for the size of the room, or the room will sound "harsh", "live", "reverberant". The decay time is chose in accordance with the room size: there's an equation for doing that, but in most typical home studios, a decay time of around 200 ms is about right. To avoid yet another "carved in stone rule", let's rather make that a target range of somewhere between 180 ms and 250 ms.

Achieving the 20-20 criteria and a smooth, even decay across the board, of about 200 ms, is the "holy grail" of control room design. If you can do that, then chances are, your room will be pretty good. This is NOT easy to do, however! If it was, people like Glenn, Andre, and myself would be out of a job! Designing the room up front with these goals in mid, is a tall order.

I guess I could build another bass trap in the middle and that might catch those rays?

At the most basic, the entire rear wall should be one huge bass trap. But it should also NOT trap too much of the mids and highs, and has to create that diffuse, smooth, even decay that arrives back at your ears after at least 20 ms, and it also needs to attenuate the levels such that the above "smooth, even etc." arrives at a level that is 20 dB down, then decays over a period of 200 ms. A single bass trap "wedge" in the middle of the rear wall is not going to do that. It might help with the bass a little, and also with deflecting some of the mids, but it simply isn't big enough to do the job.

I need to do the real math on the depth and density I'd need. Can I do that without actually testing the room fully stood up?

You can do the standard REW measurements in the empty room ( How to calibrate and use REW to test and tune your room acoustics ), and the data you get from that will help you understand what the rear-wall issues are, and thus guide you in what you need to design to get the treatment to achieve what you want it to achieve.

though I still feel like I could free up floor space for the live room

I agree! I still think there.s probably a better overall layout that would trade off some of the CR space for a better LR, without losing the "lobby", bathroom, or booth/storage.

- Stuart -

[eightamrock]

Source of the post Another issue:; If you do insist on splaying the side walls of the room, then splay them at a greater angle and don't extend the splayed part so far back into the room. Your splayed wall end very far back in the room, and are not accomplishing anything useful like that. I'd still suggest just building the room as a rectangle, and adding soffit wings to accomplish the same purpose as splayed walls would, far more simply, cheaply, and with a greater chance of being able to predict modal response correctly.

It does sound like some of these things cant be accomplished until I land on general dimensions and build the room. The walking mic test sounds like one of these things. I took your advice and decided to un-splay the walls entirely. Getting as close to a good mode as I can and then treat from there with sofits, etc.

Here is the updated sketch, I was able to free up a few square feet in the live room by removing the splay. so that helps. Its still not huge, but I think for a small at home tracking room it will do. Especially with a high 11' + ceiling.

[Soundman2020]

That looks better!

I had forgotten to post this link before: Maybe too late now, but still pertinent to the conversation. Angled walls: What are they for? Do you need them?

Question: Do you need your control room to be so big? It's nice to have a big control room if you have the space to do that, but going smaller might be a good option. For example, have you considered swapping the two rooms? Put the control room in the room you currently have marked as "LR", (facing left with a direct through that front window), and then put your LR in the one currently marked as CR... Then re-arrange the lobby, toilet and store room for a better fit...


- Stuart -

[eightamrock]

Source of the post That looks better!

I had forgotten to post this link before: Maybe too late now, but still pertinent to the conversation. Angled walls: What are they for? Do you need them?

Question: Do you need your control room to be so big? It's nice to have a big control room if you have the space to do that, but going smaller might be a good option. For example, have you considered swapping the two rooms? Put the control room in the room you currently have marked as "LR", (facing left with a direct through that front window), and then put your LR in the one currently marked as CR... Then re-arrange the lobby, toilet and store room for a better fit...


- Stuart -

Thanks, I had been struggling with that version of the layout for a while. It really puts the control room under 200ft2, but I guess in some cases that's ok. Here is a re-tooled design where I really maximize the live room at 16' x 14' (224ft2) which will also take full advantage of the 11'+ vaulted ceilings. I think that is a really respectable live room.

In this design, I shrink the control room to 13'x11'x9' which is still a very good mode ("M. M. Louden: 1971: 5th best ratio" 1 : 1.2 : 1.5). The door is in the middle of the room so I have plenty of options to plan soffits and bass traps. It would be tight for anyone coming in and listening back or working on the mix with me, but not impossible.

What I LOSE in this design is a dedicated storage closet/iso booth. In this case I have to really maximize the entry way by putting up shelving. It's also too narrow to do full room in a room construction. I would have to use resilient channel or iso clips and hat channel to hang the drywall for it to serve double duty as an iso booth in a pinch. Assuming that both the live room and control room doors have glass in them, I don't need to add any windows for line of sight.

This design works well if I really think of that entry/lobby as the iso and storage facility. Those shelves are 18" deep which is respectable as well for most things. You could fit a snare drum and most toms on them.