House built around studio design/build thread

[Soundman2020]

It looks interesting, but hard to understand from just a single 2D plan view...


- Stuart -

[Gregwor]

Does this make more sense?

Cloud 3D.jpg

I'm really having to think through light placement so that it covers everywhere well but doesn't screw up my RFZ!

Greg

[Gregwor]

I also called around/looked around at different insulation available in my area and wanted to compare price differences.

There is no 701 around. There is only 1" and 2" thick 703. I can get FRK 3" 703 but it's super expensive in comparison. So anywhere I need 3" I will use a layer of 2" and a layer of 1". For 4" needs, I'll use two layers of 2".

Where I need super thick insulation (like in my inside out ceiling skeleton where I will need 5 1/2" of insulation) I'll use OC R24. For places I don't need amazing acoustic treatment (like inside wall cavities), I'll use 3" Rockwool Safe'n'Sound.

Dimensional lumber is always 1 1/2", 2 1/2", 3 1/2", 5 1/2". For the smaller dimension wood, I can't get exact sized insulation. So, this will force me to get creative with what lumber I use where and how I will frame fabric cover frames. I'll try to eliminate gaps where possible, but I think it's inevitable in spots. This is just making the design process harder

Here are the prices I can obtain the three different models of insulation for:

$0.916 per 1” 1’x1’ for 703 with no discount
$0.209 per 1” 1’x1’ for OC R24
$0.300 per 1” 1’x1’ for Rockwool Safe’n’Sound

Now, for the 703, I can get a discount based on how much I buy at once. So I'm going to figure out roughly how much I need and buy it all at once. The place doesn't carry R24 or Safe'n'Sound as they only carry industrial grade insulation.

I'm also able to get Roxul ProRox SL960 (which is the new name for RHT80) or ProRox SL930 (which is the new name for RHT40) from a 4th place (I've bought some in the past) but I don't have those prices handy.

Anyway, sorry if this hasn't been an interesting post, but it's what's on my mind.

Greg

[Soundman2020]

Does this make more sense?

OK, that makes a bit more sense. I was actually looking at it backwards! But now I got it.

Have you thought of putting small hangers above parts of your cloud? Like this?

Hangers-in-ceiling-example-ENH-SML.jpg

Not sure if you have enough space for that, but it might be an idea.

I'm really having to think through light placement so that it covers everywhere well but doesn't screw up my RFZ!

Be careful with light glare on your front window too. You can ray-trace for light glare just like you do for speaker reflections. There should be no direct light that is visible from the mix position as you look through the window, AND ALSO nothing that is illuminated directly, visible in the window. If you have things that are visible directly in the window (such as your own head, for example!) try to only get indirect lighting on those, or diffuse lighting (not a direct spotlight, for example). It's surprising how annoying light glare can be: especially seeing your own reflection in the window as you try to look through it.

I also called around/looked around at different insulation available in my area and wanted to compare price difference....

Your insulation plan sounds about right, except maybe for this part:

For places I don't need amazing acoustic treatment (like inside wall cavities), I'll use 3" Rockwool Safe'n'Sound.

You are talking about your MSM cavities? Between inner-leaf and outer-leaf? Those should always be filled with insulation. If you have a 6" air gap, the you should have 6" of insulation in that, for maximum isolation.

Also, this:

Dimensional lumber is always 1 1/2", 2 1/2", 3 1/2", 5 1/2". For the smaller dimension wood, I can't get exact sized insulation.

Right! So for treatment devices, either go one size larger with lumber and leave an air gap behind the insulation, or rip the lumber down to the same size as the insulation. In general I prefer to use larger lumber than the size of the insulation, and leave a small gap on BOTH sides. The gap at the front is to ensure that any insulation bulging out a little too far does not also cause a bulge in the fabric covering. So, for example, if you need 4" thick insulation for a hypothetical wall absorber, then use 1 x 6 lumber to frame it (which is 5-1/2"), and leave a half inch at the front for "bulge" factor, and an inch air gap at the rear, which will help extend the effective frequency range down a bit lower.

And if you are talking about wall cavities, then you can overfill them SLIGHTLY, with care. Eg. if you have a 5-1/2" gap, then you can put 6" of insulation in there as long as it it not rigid. You can compress the insulation up to about 10% with no flanking problems. (some say 20%, but I'm not too keen on that...)

I'll try to eliminate gaps where possible,

Gaps are your friends, not your enemies! An air gap behind the insulation helps extend the frequency, and an air gap at the front helps aesthetics.

- Stuart -

[Gregwor]

Have you thought of putting small hangers above parts of your cloud? Like this?

I was planning either hangers or super chunk style. I have 3 cloud portions before the flat hanging cloud (the one that I'm trying to design the cool shapes on). The first cloud portion right above the window will not be hard backed. The next two will be hard backed. All 3 will have insulation above them.

I think I've decided to frame the first 3 cloud portions out of 2x4's and the big flat one out of 2x3's. Then I will take some 1x2's and make the fabric face frames out of those and brad nail them on. This would make a depth of 2.5" + 0.75" = 3.25". Just shy of a 2x4 on edge.

Be careful with light glare on your front window too. You can ray-trace for light glare just like you do for speaker reflections. There should be no direct light that is visible from the mix position as you look through the window, AND ALSO nothing that is illuminated directly, visible in the window. If you have things that are visible directly in the window (such as your own head, for example!) try to only get indirect lighting on those, or diffuse lighting (not a direct spotlight, for example). It's surprising how annoying light glare can be: especially seeing your own reflection in the window as you try to look through it.

Thank you for mentioning the ray tracing idea for lights and the indirect lighting idea. I've angled my control room window to help with this, but I'll do everything I can to prevent glare. It would drive me bonkers to see myself!

You are talking about your MSM cavities? Between inner-leaf and outer-leaf? Those should always be filled with insulation. If you have a 6" air gap, the you should have 6" of insulation in that, for maximum isolation.

That's what I meant. I can rip Safe'n'Sound down to size if need be to fill the MSM cavity as precisely as possible. Pink fluffy might be harder to rip accurately (my last attempt ripping it for a drum riser didn't yield very clean/accurate results). The R24 is the cheapest though, so I guess I'll have to make that decision.

Right! So for treatment devices, either go one size larger with lumber and leave an air gap behind the insulation, or rip the lumber down to the same size as the insulation. In general I prefer to use larger lumber than the size of the insulation, and leave a small gap on BOTH sides. The gap at the front is to ensure that any insulation bulging out a little too far does not also cause a bulge in the fabric covering. So, for example, if you need 4" thick insulation for a hypothetical wall absorber, then use 1 x 6 lumber to frame it (which is 5-1/2"), and leave a half inch at the front for "bulge" factor, and an inch air gap at the rear, which will help extend the effective frequency range down a bit lower.

Thanks for the words of encouragement! My current treatment is 1x6 lumber with 4" insulation. Since I'm going all out on this build, I was planning on avoiding the air gaps, but it makes sense to consider fabric bulge. I'll be lenient with thickness.

And if you are talking about wall cavities, then you can overfill them SLIGHTLY, with care. Eg. if you have a 5-1/2" gap, then you can put 6" of insulation in there as long as it it not rigid. You can compress the insulation up to about 10% with no flanking problems. (some say 20%, but I'm not too keen on that...)

That's awesome to know. I certainly don't want flanking or the compression to raise the density too much.

As a small update, I've started to design the centre section of my front wall as it will have the first section of cloud anchored to it. Playing around with the REW speaker placement simulator, I'm really wondering where I should fit my sub (I know I won't know for sure until I run acoustic measurements in real life). My from section certainly is not deep enough to hold my 12" sub. It's really going to be a trade off of bass trapping below the window, or sink the sub into it. I wish the REW program had flush mounted speakers on their simulator Any words of wisdom on this topic?

And, Stuart, I never showed you the updated hanger configuration for the my soffit. Here it is. Thanks for the suggestion on this as well!

Bottom Soffit Hanger Config.jpg

Greg

[Soundman2020]

Thanks for the words of encouragement! My current treatment is 1x6 lumber with 4" insulation. Since I'm going all out on this build, I was planning on avoiding the air gaps, but it makes sense to consider fabric bulge.

Also, if you are going to put fabric on those frames, then bevel or round the inner edges of the frame, so that they don't make unsightly lines in the fabric, Route or sand, or even run it through the table saw at an angle.

Playing around with the REW speaker placement simulator, I'm really wondering where I should fit my sub (I know I won't know for sure until I run acoustic measurements in real life). My from section certainly is not deep enough to hold my 12" sub. It's really going to be a trade off of bass trapping below the window, or sink the sub into it. I wish the REW program had flush mounted speakers on their simulator Any words of wisdom on this topic?

I'm giving away all my secretes here! Don't plan on any treatment under the center section of your soffit, between the two actual soffits. Leave that totally empty for now (you'll add the treatment right at the end. That's the zone for "playing" with your sub, to find the correct spot with the smoothest response. You can project and predict and calculate all you want, but there's no substitute for actually nudging it around the floor in that area, while you use your ears (and REW) to optimize the position, orientation (yes, that matters too!) and adjustments (phase, level, cross-over). You can also use the "reverse" trick: put the sub on a tall stand at the location where your head will be, and move your head around the floor until you find the best spot. Bass works in both directions...

Once you have found the perfect spot THEN fill in that area between the soffits with hangers, insulation, or whatever. And AFTER you have done that, try tweaking the position again, since you will have changed the tuning by adding that treatment.

It's quite surprising the difference that just a few inches move of the sub can make to the low frequency response. Worth spending time on. And frustrating, too! Do the moves in small steps.

Stuart, I never showed you the updated hanger configuration for the my soffit. Here it is. Thanks for the suggestion on this as well!

- Stuart -

[Gregwor]

I've been working and studying very hard on this stuff lately! Here is the cloud module framing I've come up with. It's a lot busier than Id like, and maybe too messy. It's just hard to hit ideal anchor points on both the centre frame as well as my inside out modules on the ceiling. I've thought about building actual modules and just hanging them off of wire but I decided that I don't want to do that. I want clean lines. The downside to the framing scheme I have here currently is that hanging hangers will be hard and I might just have to stuff insulation batts in there the best I can. I have ideas to maybe clean things up though.

Cloud Modules 1.jpg

In other news, I came across a recent thread that mentioned Tim Perry's diffuser design. That lead me to ditch my current studies and jump in head first into diffusion. After reading all of the QRDude info I could find, I played around with his calculator and thought I had a plan of attack with a 5 panel N13 array with a constant introduced into the mod operator, having 1 inverse panel as per the Barker Code.

Then I read Tim Perry's thesis paper and it threw me for a loop. Initially I was under the impression that the fins were crucial. Tim's thesis says otherwise. I really dig the benefits of fractalization even though it will make the build way harder.

So, now I'm leaning towards Tim's design purely due to the increased bandwidth. Does anyone have reasons why I would build a QRDude version with fins over Tim's design? I can easily fit a 5 panel version of Tim's on the back wall of my control room. I want the room to sound awesome for me. If it doesn't sound amazing for the people at the back of the room, I'm okay with that.

Greg

[Soundman2020]

It's just hard to hit ideal anchor points on both the centre frame as well as my inside out modules on the ceiling. I've thought about building actual modules and just hanging them off of wire but I decided that I don't want to do that. I want clean lines.

Why? I don't mean "Why do you want clean lines?". I mean "Why would hanging the cloud NOT give you clean lines?". Look at at Studio Three: That's a multi-segment cloud, that is hung on chains. I think it looks like "clean lines". In fact, you can't even see how it is hung at all! It's all hidden, and it just sort of seems to "float" there. Rod was originally planning to put concealed lighting on top, but he didn't do that in the end.

If you try to frame up your cloud support, you'll use a lot of wood, you'll connect it to your soffits (!), and you won't have any way of adjusting the angle after it is hung, if it turns out that you are getting an unexpected reflection from it, or maybe light glare, or some other unwanted issue... Chains work very well, you can attach them wherever needed up above, and you can adjust them. Of course, do follow all the usual safety precautions for stage rigging.

Initially I was under the impression that the fins were crucial. Tim's thesis says otherwise.

Right! Not just his thesis. People have been building them without fins for quite a while. Even ordinary QRD's do not need fins either. Here's a view of the QRD's that I did for the rear wall of Studio Three:

BUILD-31st-construction--QRDs--in-place--2014-07-27-photo2-SML-ENH.JPG

They work just fine. It isn't necessary to have fins.

I really dig the benefits of fractalization even though it will make the build way harder.

It's not really that much harder: just tedious. All of the strips for Tim's design can be cut on a table saw very easily, then assembled into sub-modules that get assembled in other modules that get assembled into yet others... Use a dado blade, or even a router, for the smallest elements. Make a jig to help you assemble the parts, and it goes fairly smoothly. Smoother than assembling a QRD, actually: With a QRD it's too easy to accidentally put the wrong length piece in the wrong place without noticing...

Does anyone have reasons why I would build a QRDude version with fins over Tim's design?

Having used both, I would go with Tim's design. Here's a pic from a studio I'm working on in New Orleans right now:

STVNO-USA-REAR-WALL-DSC00299.JPG

Guess what goes in that large empty hole in the middle of the rear treatment section ?

Yup, a full 7-panel version. Currently under construction. Should be done in a week or so...

I want the room to sound awesome for me. If it doesn't sound amazing for the people at the back of the room, I'm okay with that.

In a small room there's always going to be bass issues at the rear of the room. There's just not enough space to be able to fully treat that. The bigger the room, the easier it is. You can get it sounding pretty decent in a small room, for sure, but the back isn't the best spot, and you aren't tuning the room for the couch anyway! You are tuning it for the mix position, where it MUST be perfect. So having a large diffuser back there isn't going to "destroy" something that was otherwise going to be fantastic: it never was going to be fantastic back there. The diffuser just adds some uncertainty to the mid range, in addition to the less-than-tight-but-too-powerful bass. It's probably not a big deal. If you have a producer or musician back there who isn't happy with the mix, saying it's too "heavy" or not "spacious" then let him sit in your chair for a couple of minutes, and explain that the entire room is focused on that chair, not his chair. He can stand behind you or next to you if he wants a more even sound. It's only in fairly large rooms, where there is space to pull the couch a few feet forward, away from the wall, that you can get good coverage back there as well, in addition to the mix position. In the room above (which is still small, but larger than many) the ear location for people on the couch is over 4 feet from the actual rear wall, and over two feet from the diffuser. The bass is fine for them, that far in, but the mid range is going to be a bit off.

But as you say, you can live with it. It's not a huge issue for a WAG just sitting in, listening, and for someone who need to do critical listening, he can always take a few steps forward to where you are. It's not the end of the world!


- Stuart -

[Gregwor]

After some thought, messing around, and getting advice from the pros, I decided to just hang the front 3 cloud modules. I also did a quick framing of the top cloud. I need to adjust it as I want wood trim. Here are some pics.

Front Clouds From Above.jpg

Front Clouds.jpg

Overview 1.jpg

I've also started drawing up the diffuser. Hopefully I have some more design progress pics to share soon. Slowly but surely!

Greg

[Gregwor]

I snuck away to get a bit more done on the design this evening. I finished the diffuser.

Here's some info on the design:
- Based on Tim Perry's Leanfractal A1-Frac diffuser
- Built around his imperial measurements (1/2" thick wood) found on his FAQ page (one of the 7 wells ends up being 2 5/16" instead of 2 9/32". I put the 2 5/16" well as the middle one)
- The base structure (or LF module) depths were built around Tim's fabrication specs, just converted as 10mm being 1/2". So, that is 0", 2", 2 1/2", 1 1/2", 2 1/2", 2", 0"
- The fractals (or HF modules aka 2nd Stg. of Fractal) I built according to "Schaap's" sizes as per Tim Perry's instructions on his FAQ page. These sizes are 0", 13/16", 1", 9/16", 13/16", 0"
- The profiled modulation for the 5 panels follows Tim's fabrication design, but imperial as: 0", 2", 2 3/8", 2", 0"
- I took resonance and weight into consideration and removed as much material in behind as I could while retaining stuctural integrity. I should be able to fill the backs of the modules with insulation.
- There is enough material at the top of the modules to screw into through the top and bottom of the surround while installing one module at a time.

A1-Frac Side.jpg

A1-Frac Front.jpg

A1-Frac Top.jpg

For my top cloud, I was thinking, I still dislike the shapes I came up with. It reminds me of 1970 cowboys for some reason. I may experiment using depth. What I mean is, have some of the shapes not drop down the 2 1/2" and just be the black fabric frames nailed to the LVL stud and/or I/O module frames.

Bedtime.

Greg

[Waka]

Really liking the progress so far on your design Greg. It's really coming together! I really liked the look of those Leanfractal and Leanfuser designs. You picked the hard one to build! I'm looking into options for scattering and diffusion in my one room studio design, but I've got to be careful with the min critical distance as my room is pretty small. I've got the recommended distance behind my listening position to place a diffuser on my back wall, but like you say the sofa is going to suffer from bad acoustic distortion.
Have you got any good links to stuff I can read about diffusion in a tracking room environment? I'm rereading MHOA, to refresh my memory for continuing my design.
Keep up the good work!

[Soundman2020]

The best is still "Acoustic Absorbers and Diffusers" by Cox and D'antonio. That's THE definitive text about diffusers. A little heavy on the theory and math, maybe, but still a lot of good stuff in there!

but I've got to be careful with the min critical distance as my room is pretty small.

Have you consider a set of true catenary-curve based poly-cylindrical diffusers? The can do nice things for the rear of a control room if number-based diffusion is "iffy" for your room.

- Stuart -

[Gregwor]

I've started to solidify my rear wall hanger design. Homasote is just over $57 + GST of 5% here for a 4'x8' 1/2" thick sheet. Each hanger on the back wall would take half a sheet. So for every two, it will cost me ~$120 for just the Homasote. I know that hangers will work better with 2" insulation on them rather than 1". 703 is expensive, but it's much cheaper than Homasote. Therefore, I'm toying with the idea of using 2" insulation and skipping every second hanger (to hit the 1/2, 1/4, 1/8, 1/16, etc as per John's design).

Do you think this is a reasonable trade off, or should I fork out the extra $1000 to do the rear wall with twice as many, half as thick hangers?

The guidelines are where the 1/2, 1/4, 1/8, 1/16, etc are. I will cut the tops off of the middle hangers as they will have the diffuser at them. Also, this is clearly just half of the room.

Rear Wall Hangers.jpg

Greg

[Soundman2020]

Therefore, I'm toying with the idea of using 2" insulation and skipping every second hanger (to hit the 1/2, 1/4, 1/8, 1/16,

That should work fine, as long as there's a little space between the hangers. They can't be touching.

- Stuart -

[Gregwor]

I know this thread has been quiet for a while.

I've been studying a ton - thousands of pages of pretty heavy acoustics theory. Also, I've been doing normal life stuff like work, raising kids, and spending quality time with the family.

I learned a lot with Blender, the 3D modelling program, but was disappointed with it's lack of inferencing, measuring, and unit protocol. I feel like I wasted so many hours exploring it. However, it is a very very amazing program. Blender just doesn't work well for designing studios!

Our house is almost done. We should move in in a month or so. That's where a lot of the lack of updates has rooted. Until I can spend some serious time taking more measurements in the basement, I'm not sure how much space I have for my designated HVAC system and silencer boxes that live outside of my recording area.

There are a few specific topics I want to try and find some literature on, but for the most part, I've studied everything I have. So now, it's time to put it into practice on my personal design. I'll get back to finishing details, but to utilize my time I figured I should cover my ass and make sure I go to the building permit people with all of my ducks in a row. So, last night I started drawing up 2D building details. Here's the first easy one I did. I'll make a bunch so there is no chance of denial.

Interior MSM Wall Detail.jpg

Greg