John Sayers' Recording Studio Design Forum

My studio is currently Under construction still in a very raw stage. I Have 2 rooms devided off in my basement. Currently only Building the Controlroom.
Ceiling, Floor, Front and Rear walls are Concrete 25 - 30 cm thick. the Dividing Walls Left and right are 5cm Metalframed Giprock with Double Leaf first is a normal 12.5 leaf covered by a 18mm highdensity leaf. The core is filled with 5cm of Rockwool.
Unfortunatly I came across the inside out wallconstruction alittle late. First comes a dividing layer of Fiberglass compressed insulation plates 2cm thick then the The Inner room is framing with metalframeing this time with wooden supportbracing inside the metalframeing. filled again with Stonewool of 5cm and the same 2leaf Giprock panels to finish that off. This all is builtup on a European Floating Floor. 6cm thick of high density Styrofoam where later a floorheating system will be built up on.

Room measurements Inside of Isolated room Orientation Mixer sitting forward facing outside window

- Front facing wall (has a window to outside 150cmW by 50cmH off center to the left of the room and only 2cm below the finished ceiling) Hight 240cm, width 307.7cm wall is in level.

- Rear Facing wall (has Fusepanel for Studio top leftcorner) Hight245cm, Width 323.7cm wall is slightly angled forward top is 5cm closer to the front wall.

- Left Facing Wall As other wall dimenions say the wall is angled front narrower point rear wider. ( Has a door to the heating room. right near the back wall approx 10cm away from rear wall) Length is 263.0cm

- Right Facing Wall diddo to Left Plus ( Has a window to the second Studioroom, ev. Liveroom window is 100cm from finished floor up 90cm wide with a hight of 80cm)

- Ceiling has two different hights in raw build. front section is the width by 100cm Long finished with Giprock panels . Second section is inside out with open Cavity of 95cm for Acoustictreatment. The front section I cant remove any hight because of the window.

The room I believe has enough Isolation for my needs.Approx 90 - 95 Db(a) in room with a peak around 100Db(a)

The second room is raw I'll Add Dimensions of that room asap. Will not start there though for some time.

As soon as I figure out how to Reduce my Picture file Size on my Mac I'll Add some of the current stand and progress pix.

The Controlroom I was planning to do vocal recording in as well as My space is limited and dont want to lose to much space in the other room for an Iso Booth. But that is still open.

Budget is Flexable In this room I have 3500chf plus in materials so far, can do another 3500.

My ?

Most CR's I've seen here have alot of wood finish with slot resonators and Hangers. Is that All I need to consider.Or Cloth finish over 5cm Rockwool to Absorb Highs as well?

Inside Accoustic treatment Suggestions would be Greatly Appreciated As well as Layout Ideas.

And for the cloth covering behind the Slot resonators What kind of Fabric should be used here to Keep the Insulation dust etc. where it should be and not in my Lungs ( Breathed enough so far ) Is rockwool the best idea for the treatment or a combination? and how thick should it be behind such a resonator. or on the MDF on Hangers.

I Hope I did this post correctly for the Forum Rules. Anyone have anyidea's on how to compress pictures on a Mac to a smaller format so I can upload My Current Plans and Status Pictures. That would also be of great help.

Thanks for your Help You Have an awsome Site Here Cheers!!

Hi "ReneO", and welcome to the forum!

I'm trying to understand what your construction looks like, but I'm not getting a good mental picture. Maybe you could do a model of it in SketchUp, then post it here so we can see how it is built?

12.5 mm wood or drywall is too thin to be optimal for isolation. Even though you have a good 18mm layer or HDF next to it, the 12.55 layer will still resonate and vibrate at some frequencies, which willweaken the isolation of the room.

A gap of 5 cm is too thin. The gap between the leaves should be at least 10 cm, preferably 15cm.

When you say "floating floor", you are talking about the marketing sense of that term, not the acoustical sense, right? In other words, there is no framwork under the deck, and no air gaps: just that layer of styrofoam with a wood deck on top, and nothing else. Is that correct?

So if I understand correctly, your room measures 307.7cm (front wall), 323.7cm (rear wall), 263.0cm (both side walls), and the height changes from 240cm at the front to 245cm at the back, with the rear wall leaning in slightly (5cm)at the top.

Is that right? If so, then you need to fix that. First, you need to reorient the room so that the "front" of the room is on one of the short walls, not the long walls. In other words, the speakers should be aiming down the longest dimension of the room, not across the short dimension. The reason for this is to maximize the distance that sound must travel before it bounces back to your ears from the rear wall, so that it does not arrive until after the recommended delay, and with the recommended attenuation. Also, if the room is only 2.6 m deep, then it will be practically impossible to get your head in the correct location, and most likely it will end up in roughly the middle of the room, which is the worst possible place.

So change your room around such that the front is one of the 263 cm walls, and change the angles of the other walls correspondingly. You'll also have to correct the "tilt" of that wall that is leaning over 5cm.

I doubt it! The very best isolated studio in the world (Galaxy) has isolation of around 100 dB, but that one costs millions of dollars to build. The entire studio is suspended on huge springs, the floor decks are massively thick concrete, and the air gaps are big enough to walk in. There's no way you are getting 100 dB of isolation from what you describe. You are probably getting more like 60 to 70 dB, maximum.

Cloth finish over 5cm of Rockwool will absorb ONLY the highs and mids: it will not do much at all to treat the lows. In a small room like that, your problems will be in the lows, not the highs. The hangers are one way of dealing with that, as they are good at absorbing lows. Slot walls are good for general broadband treatment in the mids while also reflecting enough highs to keep the room live enough, even treating some of the lows, and also diffusing somewhat. If you don't want to use hangers, then you could use superchunks instead. But bass trapping in a small room like that is very, very necessary.

The idea is to balance the treatment for each frequency band so that you end up absorbing just the right amount to get the reverberation time for that band into the correct range. Normally you install some basic treatment then test the room acoustically to see how it is responding and what sill needs to be done, then you add additional treatment for the problems that you see during the test.

You can use any type of fabric that is "breathable". In other words, if you hold a piece of the fabric across your mouth, can you breath trough it without noticing any resistance at all? If so, then that will work.

A "combination" of what and what? Rockwool is fine, provided that the density is not too high. Fiberglass is also fine.

10cm or so should be enough. If you make it thicker then you absorb better but that also lowers the Q of the resonator a bit. That might be good, or it might be bad, depending on what you designed the slot wall for.

The hangers are not made of MDF: they are made of "Homosote" (also "Homasote"). It is a very low density type material, the type that they use for bulletin boards, where you can easily stick pins into it.

- Stuart -

_________________
I want this studio to amaze people. "That'll do" doesn't amaze people.

I'll post some pix tonight hopefully that gives you
Better picture. Sounds like I made alot of wrong layout choices
Oops. In regards to the Isolation I meant that 100Db(a) is my approx
Volume level not my Isolation levels sorry.

Thanks Stuart I'll get those pictures up ASAP!

Ahhhh! OK, that makes more sense. So this is just a control room (mixing room), with tracking only for vocals, right? I mean no live instruments, such as drums, trumpets, bass cabinets, electric guitar cabinets, etc. Those are all louder than 100 dB, usually. Also, for loud sounds it is usually better to measure with "C" weighting, not "A" weighting, as it give you a more realistic representation of what humans hear. "A" is good for low levels and for machinery, but "C" is more appropriate for high levels and music.

Look forward to seeing the photos!


- Stuart -

_________________
I want this studio to amaze people. "That'll do" doesn't amaze people.

Pictures hope this Helps, Gotta run to school.

Last few Pix. Hope this Helps Clarrify )

Corrections that I need to make if I understand
You Stuart right is. Correct the angle of the rear
Wall so it is straight. And the 2 side walls so they are
Parallel. When I correct the 3 side walls I will then have
Inside raw wall measurements from
Width 265.0cm.
Length 304.5cm
Hight 240.0cm
Then the wall that was the right Side would now be the
Front Orientation. And the come problems that I see of
Speaker placement etc because of the door and window
Any ideas here? Or would I be better off using the other room
For the CR. and using this one as a Liveroom
It's measurements are now
Width 285.0cm
Length ca. 400.0cm
Hight 260.0cm
All raw no room in room yet but the problem I still see I
Have would be the current window and door.

Thanks for your input.

I'll add a sketch of the 2 ground
Plans with measurements of the complete room I have for use
Tonight.

A Pile of ? Trying to build myself a mental picture of how to solve my Design Problems. Haven't gotten a handle of Sketchup Yet Working on it though. Would a CAD Diagram work 2 ?

What are the consequences of staying with a wider than Long CR. Is it acoustically solvable with treatment?

Is A Fresh air Porting HVAC system a muss have. in a studio?

And Can I combine a Slotresonator wall with Hangers Behind it Would that work for Killing the LF in the CR?

The outsider walls are front, rear, ceiling and floor all Concrete Slab. then the Left and right are as in the Pictures. 18mm HDGiprock, 12.5mm Norm Giprock, Framing 5cm filled with Rockwool,12.5mm Norm Giprock, 18mm HDGiprock. 2cm Condensed Fiberglass, 5cm Framing filled with Rockwool, 12.5mm Norm Giprock, lastly before inner treatment is 18mm HDGiprock. Then Whatever I Need for Inner Treatment.

So Again a big mistake from Me (Missunderstood what you meant as leafs) Right now front rear Ceiling and Floor are Double Leaf where as is currently the 2 side walls are 3Leaf right wall when the Liveroom is built will be 4Leaf total. ). Should have spent more time reading and planning before starting the Build

I Hope My Hand Sketches are ok for You all until i get a Grip on Sketchup

P.S. the Scale is Mst 1:10 roughly 2 squares = 10cm so from the finished inside treatment the room would be slightly longer than Wide from Slotresonator to Slotresonator. would that solve my problems a bit?


Rene,

2D CAD is better than nothing, but SketchUp beats the pants off it!

I have to agree: SketchUp is pretty confusing when you first get started, but hang in there a bit, follow the tutorials, and you'll soon get the hang of it. Once the strange concepts "click" in your brain, it all comes together and you realize just how powerful it is. Frustrating, sometimes, but very powerful.

The question isn't so much wider vs. longer, as it is the position of your head in the room, overall, and the distance between your head and the rear wall. In a large room, it doesn't really matter which way you orient it, but when the room is small then going "crosswise" instead of "lengthwise" puts your head too close to the rear wall. Theoretically, you want at least 10 feet between you and the rear wall, in order to keep the round trip time over 20 ms, or at least the total distance from speaker to rear wall and back to your head should be 20 feet. The reason is that your brain can easily distinguish the same sound coming at you twice, delayed by more than 20 ms, and it know that it is a reflection (echo), but when the time is less than 20 ms, your brain has trouble with that, and thinks it is separate smudgy sound. Makes it harder to distinguish details in the mix, can cause sounds to appear to come from places other than where they really are (messing up your perception of stereo image), and other nasty things.

So basically you want to maximize the distance. In a big room, no problem But in a small room, it's hard to do anyway, and even harder if you don't use the longest axis you can.

There's not much you can do to treat it, either. You might be able to make the average path longer by judicially angling lots of surfaces to keep things bouncing around, but I don't think I'd want to try that! Absorption will reduce the level of the sound (which is good) but won't delay it. Diffusion would help, but you can't use diffusion in a small room anyway.... so things are just against you, all around.

You need something to cool/heat and de-humidfy the air, for sure. The room will be very well insulated, and people plus equipment produce heat. You also need to bring in fresh air, because people have to breath! And if you bring in fresh air, then you also have to exhaust the same amount of stale air.

So you can do that with a single HVAC system that does both, or you can do it with a simple "mini-split" system for the cooling / dehumidifying, and a separate fan-and-duct system for moving the air.

Hmmmmm.... good question! I don't think that would work very well, since the cavity behind the slot wall will only "see" the frequencies that the various parts of the wall are tuned to. What you COULD do, is to make the slots wide enough that there is not much Helmholtz effect going on, and also NOT seal the cavity: If it is not sealed, then it won't work very well as a Helmholtz resonator anyway.

But on your diagram, the cavity behind the side slot walls seems to be VERY deep, so those will be tuned very low. Did you calculate the frequencies?


Could you draw a diagram of that? It sounds like a three-leaf wall for sure, maybe 4 leaf in places, but also coupled: it seems like the two sets of framing are also joined to each other through the center layer of drywall? Or at the very least, there is drywall on each side of the first set of studs, so that is all coupled, or sure. But in any case, the air gaps (distance between one leaf and the next) are very small, so the resonant frequency will be high, and the wall will not isolate low frequencies well. On the other hand, there is a lot of mass on there, so that will compensate to some extent.

OK, that sounds like what I suspected. Is there any way to fix that easily? Is it all done already? I guess you used screws for the drywall (metal studs) so you should be able to take that off fairly easily, without damaging the drywall, the re-use the drywall later.

It gives a rough idea, but the 3D model in Sketchup would make it much easier!


- Stuart -

_________________
I want this studio to amaze people. "That'll do" doesn't amaze people.

Got frustrated with Sketch up so i made another attempt at a hand Sketch hope this helps i'll add a couple with the wall and Ceiling build up specifics so its easier to see where I really am in the build and what i need to do to correct it.

Try to centre the speakers (in their respective baffles) in order to maximize the baffle effect this may entail changing the angle and altering the overall geometry with the LP. As it seems, you're using 90° - nothing wrong with that, but 60° is also typical and may give you better imaging in this case and as it looks you have enough room to play with the LP some, 38% from front wall is a guideline but not a rule. Better would be to set up the speakers in the desired configuration (sans soffits) and run some tests even if only listening tests, to see if the geometry is satisfactory. Geometry of the LP in relation to the speakers and boundaries is critical, and soffits will lock you into a specific, possibly poor (if not well calculated) configuration!

_________________
Brian
As you slide down the bannister of life, may the splinters never point the wrong way...

Ok Thanks Brian,

I'll do that and correct the diagrams. Still need to make some sketches of the side walls and wall build ups. I'll try to get that done this weekend and post them. Trying to make optimal use of a very tight space to work with. So if i understand that right then, my speekers ideally would be in the middle of the angled soffit surface. Stuart said I should turn my plans 90 deg so I would use the longest room depth. I tried to work that in but for my room I won't get any symmetry that way because of the front window. Its to tight to the existing ceiling. I will sit down to the drawing boards again and look to see what i can do. Hoping I still can get a CR that works properly.


Thanks for the tips Brian

P.S. Does it matter if my Desktop butts up right agains the Soffit, or is that a problem because of the Hanger ports on the Bottom. Or could one move that Port to the top of the Desktop so the port functions properly ?

Agree with Brian: Get the speakers closer to the center of the soffits. 2/5 of the width is a good place.

But also... you are aiming your speakers at the center of your head: unless you listen with your eyes that isn't the best aiming point! Since your ears are on the side of your head, the speakers should be aimed at them, and therefore the intersection of the speaker axes will be a few inches behind your head. If you just slide your speakers a bit further along the soffit panels, you should get there easily, and that will also help to get your speakers closer to the middle of the soffit panel.

2/5 is supposedly the optimum position, but middle works OK too. You can adjust the soffit angle and listening position to get there.

I don't see why the window is a problem for symmetry: You are completely covering that window with either soffits or treatment (depending on orientation), so it is not an issue. Besides, there isn0t much difference between the reflectivity of glass and the reflectivity of drywall, so the fact that the window is off-center in that wall is not very important, even if the window was not going to be covered.

That's not a problem. Leave the port where it is, at floor level, where it is most effective. The hangers and that port are dealing with the general bass field in the room, not really bass coming down the front of the speaker soffit. I would still try to leave a small gap between the edge of the desk and the front of the soffit, if possible.

- Stuart -

_________________
I want this studio to amaze people. "That'll do" doesn't amaze people.

Thanks Stuart,

? I was just thinking if turning my front of the CR 90 degrees considering how
Short my room is either way, if it will make much of a difference. Cause it's too short anyways
That's why I put the super chunk along the rear wall to try and absorb as much as I could to try and solve that problem. With its current orientation I was hopeing to gain room for treatment on the side walls.
? 2 how neccesary is it for me to cover that window I was hopeing to retain some natural light in that room. By working around that window with the soffits etc.

Thanks again for the input both of you Stuart and Brian.

René