Starting from scratch. DIY studio inside a hangar.

Hi all, me and my bud are considering building a new DIY home studio. It would be built inside a big hangar behind his house. This is great news, as the space available is virtually limitless. This is also bad news, as it's harder to get started when there's no absolute restrictions. Setup: Live room / control room Purpose: mixing/tracking pop, rock and everything in between Size: 5 people per room (including engineer) Attached you'll find the control room design I came up with. I started from a 3m height, used 1,6/1,38 room-mode dimensions for width and height and tried to fit in the most common elements from John's control room design. Questions: 1) Is this too big, or too small for 5 people? 2) What distance (engineer-speakers) should I choose for the speaker placement (softfit) 3) Did I overdo the angles? front is 30°, sides and ceiling are 12°

Aloha and welcome to the forum,

1) Is this too big, or too small for 5 people?

I have a similarly sized room and found that it's spacious for 1, comfy with 2, & cozy with 3 (hey, watch that elbow). Any more (2-3), and I would definitely have them hang out in the lounge.

2) What distance (engineer-speakers) should I choose for the speaker placement (softfit)

38% from the front wall is a good place to start (roughly 1835mm.)

3) Did I overdo the angles? front is 30°, sides and ceiling are 12°

30° for the soffits are fine. If you do decide to go with dimensions, you may consider 6° each for the sides. 12° is fine for the ceiling. That all being said, if your location and budget allows, I would go for a little larger room. In Rod Gervais’ book “Build it Like the Pros,” http://www.johnlsayers.com/phpBB2/viewtopic.php?t=5670 he points out both L.W.Sepmeyer’s & M.M. Louden’s formulas most widely used in professional studios worldwide. He also notes that the orders listed are (top to bottom) the first to third best ratios in both cases. L.W. Sepmeyer Height Width Length 1.00 1.14 1.39 1.00 1.28 1.54 1.00 1.60 2.33 M.M. Louden Height Width Length 1.00 1.40 1.90 1.00 1.30 1.90 1.00 1.50 2.10 Eric Desart on Louden’s Ratios http://www.johnlsayers.com/phpBB2/viewt ... ght=#64490 1.00, 1.35, 1.85 Here are a couple of excerpts from the SAE Website http://www.saecollege.de/reference_material/index.html that might be helpful as well.

the first thing you must do is eradicate all the parallel walls in a studio design. I believe that a wall must be at least 12 degrees off parallel to stop parallel wall standing wave interference. That's either one wall at 12 degrees or two walls at 6 degrees each. If you can afford to make the angle bigger, do so. Also you can create angled walls within a rectangular room by adding acoustic treatment. (I'll demonstrate that in the pages on wall treatment). (Note: having non parallel walls doesn't entirely stop standing waves - they still form within a room but along different lines of repetition). The main reason for having angled walls in a control room is because of reflection control of the high frequencies for true imaging from your speakers. This effect also happens between the floor and the ceiling so to stop the effect you must angle one! well it's not going to be the floor is it. I must state here that putting angles into the ceiling is expensive so I would recommend that for the home studio you use the acoustic treatment to break up the ceiling.

So what size should a control room be? These days people are building bigger and bigger control rooms because so much happens in the control room now. Often the bass player and keyboard player actually sit in the control room. I often have the vocalist singing in the control room while the bed tracks go down, so a good size control room is a good idea. So many people think that you need a big studio and end up putting a poky little room at the end and call it a control room. I suggest that a control room ideally should be at least 6m x 5m with a minimum ceiling height of 2.4m. This size room means a good sized working area with space for the musos, friends and hangers on. Also because you don't want rear reflections to interfere it is better to start with a longer front to back dimension than the side to side dimension. i.e. 6m x 5m. The studio, on the other hand, requires a different set of considerations. The first to consider is do you want just one room or more? The trend nowadays is for more than one studio so the you can get isolation between players and different acoustics for each room. The acoustics you want for a live drum sound is totally different than you want for a vocal for example. I recommend at least 2 rooms. You can put drums in one, guitars in the other, keys , vocals and bass (DI) in the control room or maybe the band in one and the vocalist in the other. Getting separation between guitars and drums is usually OK in a good sized room but keeping them out of the vocal track is hard if they are all in the same room.

Hope this helps, Aloha 8)

Tnx, it helped a lot already. I ordered the book last week, but I got impatient and just had to ask the questions in my mind so I could get on with the design. I'm losing sleep over this... :lol: 1) I might think a little bigger then. The size is comparable to my bedroom (by chance), and it looked as if it would be big enough though. I'll have to try it out in a room with similar dimensions... 2) In my current design I've used _the 38% rule as a starting position _made the distance rear wall-engineer about 3meters _used the proportions described by the formulas, choosing the one which allows reasonable ceiling height with limited surface dimensions My question wasn't meant to adres the listening-position. Maybe it could be rephrased as followed: what would be a good distance engineer-speaker (and thus also a good distance between left and right speaker)? In my current design I've tried my best, but I can't seem to manage a design with good speaker placement (which minimizes early reflections from control desk) AND combine all conditions listed above AND still find enough room to fit in a window in the front wall. 3)

If you do decide to go with dimensions, you may consider 6° each for the sides.

What do you mean? I remember reading a post by John, saying 12° was preferable over 6° on side walls. So many posts, wish I knew where I'd read it... About these dimension formulas for optimal spreading of modes: Maybe i got it wrong, but I took the proportions suggested by these formula's as wall dimensions of the inner room structure in a 2-wall isolation system. This means I did not take in to account the acoustic structure inside the inner room when calculating optimal mode spreading. Is that the correct approach? Start with a rectangle room, give it proper mode-dimensions, then fit in the acoustic walls/absorbers/etc... Love your forum here people. Big fan. It's amazing how fast I'm learning reading the posts here. Cheers from Belgium, Sigert :D

Aloha,

What do you mean? I remember reading a post by John, saying 12° was preferable over 6° on side walls. So many posts, wish I knew where I'd read it...

Yes, I'm sure you did. (Perhaps it was even the post above and below :wink:) What I meant was, if you decide to go with your current dimensions which were a little on the small side, you may want to consider using a 6° splay per wall. This would give you a little more elbow room when using those dimensions. John did state that

If you can afford to make the angle bigger, do so. http://www.saecollege.de/reference_material/index.html

Note the bold emphasis pertaining to your questions.

the first thing you must do is eradicate all the parallel walls in a studio design. I believe that a wall must be at least 12 degrees off parallel to stop parallel wall standing wave interference. That's either one wall at 12 degrees or two walls at 6 degrees each. If you can afford to make the angle bigger, do so. Also you can create angled walls within a rectangular room by adding acoustic treatment.

Is that the correct approach? Start with a rectangle room, give it proper mode-dimensions, then fit in the acoustic walls/absorbers/etc...

Yes, that is correct. It should be pointed out that somewhere around here it was stated that once you start introducing angles into the design, the difficulty in calculating the modal response increases exponentially. Aloha 8)

Aloha, Another thought after studying your design: you may want to change the rear side walls and rear wall to a absorptive design rather than slats. :wink: Aloha 8)

Hey hey kids! It actually starts making sense now. Tnx a bunch :lol: I'll change the rear side wall and rear wall to absorptive. Does this choice vary with room size, or is it a general rule of thumb? Still a bit confused over speaker placement. I'm gonna give it another go and post the results as soon as I have some. Easier to start questioning from an existing design rather than a theory. About the hangar: I'm going over someday this week to take some pictures of the construction. It's brick walls (double walls I think), concrete floor and concrete beams which support metal roofing. In theory: what would it take for this hangar to work as the outer wall of a 2 wall isolation model? It seems to me that, once we get the roof isolated, it would give us the opportunity to have a very large airspace between inner and outer wall of the construction. Or am I seeing this wrong and should I better build a 2 wall system inside the hangar? Cheers, Sigert

Made my first ITB desk design this evening. Starting from there I put my speakers up 1,15m and angled them 8,5°. This should give a wide enough path for all of the sound produced by the speakers to reach the ideal listening position at 38% from the front window. No immediate questions, still... open for comment. :wink: For details on the desk design, see my separate thread here... http://www.johnlsayers.com/phpBB2/viewt ... highlight= Cheers, Sigert

Aloha,

Does this choice vary with room size, or is it a general rule of thumb?

For most of the home studio size/variety designs, I think you'll find this to be a general rule of thumb. Once you start getting into larger rooms, you may begin to find some diffusion products incorporated.

Still a bit confused over speaker placement.

Here are some bits of information I've picked up sifting through the forums along the way - • Soffits angled 30 deg. in from a flat wall result in speaker baffles being perpendicular to the two legs of equilateral triangle comprised of two speaker centers and a point about 10" behind your head • The baffle extension (the face of the soffit) should be as large as you can make it, up to about 45" in each direction from the woofer in a system with a LF cutoff of around 45 Hz - There's a formula based on LF cutoff that ensures full 2 pi response for the woofer if the baffle is at least the size obtained in the formula's solution - • Monitors should NOT sit on the console but behind, placed on heavy decoupled stands - console placement causes early reflection problems in most cases, unless the console is slanted down in front a LOT. • Distance to wall behind speakers will change response drastically - there is a wall bounce calculator on the Acoustics forum that's fun to play with (needs Excel) • Moving either speakers or your head by as little as an inch or two can sometimes make drastic changes in response, due to modal peaks and dips. • Left/right room symmetry (at least within a foot or two of ear height) is important for good stereo imaging. • Equilateral triangle formed by left, right, mix position • Monitor angles 60 degrees • Monitor height – avoid mid point of floor to ceiling measurement – either sit higher or lower if necessary Hope this helps, Aloha 8)

Waauw, that's brilliant. I'll fix up a new design tonight. :lol: Cheers, Sigert Ps. I'm trying to put up an avatar, but can't seem to size it down enough under 6K. Oh well... 8)

Took some time to find a good spot where reflections off of the desk would be minimal, but I think I found it. Center of the front-side walls 1266mm height angled 10,5° I managed to fulfill all the criteria from the previous post, except:

The baffle extension (the face of the soffit) should be as large as you can make it, up to about 45" in each direction ...

45" that's about 1,10m right? I barely reach 0,5m sideways. Didn't want to reduce my window width. Troublesome? There's two things still unclear though:

• Monitor angles 60 degrees

Does this mean they should be angled forward 60°? That seems a lot.

• Monitor height – avoid mid point of floor to ceiling measurement – either sit higher or lower if necessary

Is this floor to angled absorptive ceiling, to inner leaf ceiling or outer leaf sealing. I suppose it's inner leaf ceiling, but I'm quite picky on details. 8) Cheers to you all, Sigert

Aloha,

I managed to fulfill all the criteria from the previous post, except: Quote:The baffle extension (the face of the soffit) should be as large as you can make it, up to about 45" in each direction ... 45" that's about 1,10m right? I barely reach 0,5m sideways. Didn't want to reduce my window width. Troublesome?

The info is based on an ideal configuration. Obviously, as in the case of most home studios, some margin of compromise will be encountered. I think the key words are "as large as you can make it." If all you have is 0,5 then that's what you work with.

There's two things still unclear though: Quote:• Monitor angles 60 degrees Does this mean they should be angled forward 60°? That seems a lot.

The angle of the speakers is set so that they create a 60 degree angle at the focus. If you want to mount them high you must angle them down so that they point at the engineer. http://www.saecollege.de/reference_material/index.html

(30 degrees per speaker/soffit)

Quote:• Monitor height – avoid mid point of floor to ceiling measurement – either sit higher or lower if necessary Is this floor to angled absorptive ceiling, to inner leaf ceiling or outer leaf sealing. I suppose it's inner leaf ceiling, but I'm quite picky on details.

Actual (before acoustic treatment) ceiling. Aloha 8)

Oh right, those 60°... Forgot about those. They're in the design though. Time to go to bed now. ZZZzzzz Cheers, Sigert

I'm satisfied with the concept of my desk design, so it's time to get back to room design. I've enlarged the dimensions according earlier suggestion, and keeping in mind Mr. Desart's interesting thoughts on the ratios. Now, there's a second thought that strikes me: I see most side walls treated with slat absorbers thus keeping the higher frequencies alive. As much as I understand and support this point of view, why aren't the point of first reflection treated to absorb full range? I assume this would be desirable since the main listening area should be free of early reflections, no?

Aloha, I seem to remember reading a post by John stating something to the effect of a general movement from a totally dead front half/live rear in control room design (LEDE) to a more subtle approach of dealing with establishing a RFZ. If I can find the thread I'll post it for you. As I understand it, the angled slat walls direct the reflection to the rear of the control room to be absorbed. Aloha 8)

That'd be fair enough. I'll figure it out and post my findings. LEDE: "Live end, Dead end" - acoustic design from the 70's Edit: I fiddled a bit in 2D to see where first reflection points would be with angled side walls. My conclusion may be rather "duuuh"-like, but still: Angled sidewalls do not treat Early Reflections. They're simply there to avoid standing waves.

Sigert wrote:

Angled sidewalls do not treat Early Reflections. They're simply there to avoid standing waves.

actually, the angled walls do prevent the reflections when properly designed and nothing stops standing waves except the outdoors... they do help eliminate flutter echos though... with bass trapping behind the angled walls, you also get the benefit of trapping the corners where room modes are strongest. by having angled walls in the back with diffusion and absorption, you can reduce the level of the reflections to something that won't interfere with the mix.

nothing stops standing waves except the outdoors...

Do you mean the only thing stopping a standing wave is having no walls in the first place? That sounds logical, but just making sure I got that correctly.

...they do help eliminate flutter echos though...

Right, I mingled up a few terms there. Flutter is the one I had in mind.

by having angled walls in the back with diffusion and absorption...

Does this still refer to those areas on the side walls which result in first reflections (under 20-30ms) into the main listening position? I'm still having the feeling the initial question goes unanswered though I'm afraid. In many designs I've seen on this site, the side walls in the area near the main listening position are treated with slat absorbers. This type of absorber is, by design, range specific, right? But all frequencies outside this range will either pass through or reflect off of the surface of this absorber, no? And I'm not talking bout a portion of the energy being reflected, I'm talking bout nearly all of it since the wooden slats are quite reflective. Should it not be considered then to treat these spots, these primary reflection points who're supposedly bombarding the RFZ with early reflections, with a 'full' range absorber? By this question I do not suggest a LEDE design. I'm merely looking to get my head straight. 8)