John Sayers' Recording Studio Design Forum Archive

Hi, absolute newbie here.
I promise you that I did do a LOT of reading, and visited pretty much every single forum and site referenced here or elsewhere in the last couple of months. The information is so diverse and plentiful that my brain hurts. So, let me try to keep it short and to the point, but before I do, just a couple of remarks:
I am from South Africa and most of the materials that I find mentioned does not translate to anything here… except for gypsum (drywall) and particle boards and similar ‘universal’ materials. No neoprene pads, no heavy fibreglass boards, and certainly no such thing as ‘acoustic grade’ anything… Actually, who knows? But I am too old as is, trying to source all the special stuff would put me in the age bracket where I would not be able to hear anything anyway ;-(

OK, so I’d like to turn a rather small garage space into a practice room (full band) and possibly (funds and space allowing – counting desperately on your input here!), into a demo-recording space. I am talking about a double garage where one half (along the longer side) would be ‘expropriated’. That half would be roughly 10’ x 21’, roughly 8.5’ to the roof beams – there is no ceiling at present! No windows or doors except for the garage for.

Now, here’s what I’m thinking:
- I would make the length of the usable space shorter by about 3-4’ allowing for the garage door to swing open.
- I would build a room-inside-the-garage, where one longer and one shorter side would ‘share’ the existing solid garage walls (double-brick wall, 10”), with necessary isolation – we’ll get to it later.
- Since the garage floor is a very solid thick concrete slab, and the weight of the sub-structure would be pretty evenly distributed, I do not worry about the additional weight constraints.
- For that reason, (tell me what you think about this one) instead of using the usual floating-floor wooden frame method, I would go like this: cork/rubber padding onto the concrete garage floor and under the first row of cross-members (acting as stumps?) where I would use concrete ‘lintels’ instead of wood - cheap and heavy as hell. They are roughly 3”x4” profile, steel reinforced and available in many different (prefabricated) lengths.
- Then, the next section perpendicular to the lintels, would be pine ‘joists’ in 1.5”x1.5” – low ceiling, have to preserve the space.
- From there, the usual floating-floor recipe – particle board, synthetic wool insulation (the only decent stuff available here is polyester wool, would that be OK?), some air gap (how much?) governed by another perpendicular set of joists, next layer of particle board, roll-roofing (if I can find anything like that, if not, water-based roller painted rubberised bitumen – great stuff for flat roofs),
- Then, again something ‘outrageous’ – 0.5" drywall, covered by thick vinyl (what do you say?). OK, that’s the floor. That was a rather conventional part
- Walls: I will gladly adopt the dual-leaf, spaced (no internal contact) using the thin metal sheet verticals. I have no idea what that is called in US/UK or even here. But I know what to ask for in the hardware shop
- Ceiling: same method as the walls.

Now, since the inherent problem with perfectly air-tight room is exactly that - they are air-tight - the resulting vibrations and ever-dangerous air pressure from the low-Hz instruments would be unbearable to residing humans and render the space useless both for humans as well as recording unless a serious amount of money and effort is spent into ‘humanising’ the space by adding all sorts of reflectors, deflectors, bass traps, you name it… So, at the risk of being called names Z:-), I must admit I was thinking about the following as the possible budget, yet perfectly performing solution:

- Apply the slotted-wall principle, hoping that it would absorb the low to mid Hz and at the same time allow the room to breathe, but in the following way:
- Drill many random holes of different radius in the inner leaf (oh, terror!)
- Add another leaf (oh, terror!) with exactly the same construction principle – air gap, polyester wool, leaf, except:
- The final inner leaf would be made of wood (particle board as the cheapest case scenario) and entirely according to: http://johnlsayers.com/HR/index1.htm principles for corner and side-wall slot resonators.
- Existing solid walls would also receive a treatment of polyester wool and then a leaf of drywall and then a leaf of particle board slot-resonator wall, same as new ‘interior’ walls.

You see what I mean? Practically a dual set of absorbers, except that the first (inner) one would be entirely conventional and totally according to John’s recipes, while the ‘middle’ one’s purpose would be to aid the venting (breathing) of the rather small space. Am I totally off track here, or is there still hope for me?

Ceiling would be done in exactly the same way, or whatever the consensus of the wise-old-men is…

I would most definitely budget for HVAC, but I’m lost at that one – I looked into Steve’s and Thomas’ ideas and diagrams under the FAQs, but I am not sure whether you guys consider those to be final, or was just an idea? Has anyone tried? Thomas, wouldn’t the plenum chamber be enough to de-noise the incoming air, without having to have the active cancellation? And, for the exhaust air, wouldn’t in be better to have the plenum immediately outside of the live-room, instead of inside the room? The centrifugal blower that both of you mention – what exactly would that look like and what kind of rotation speed do you have in mind? HVAC unit itself – are there any split-unit types that actually allow for fresh air intake, or are they all made to just for recirculation of the inside air, hmm?

What can I say except apologise for the this NOVEL that I wrote… but you guys always ask for more detail, anyway!

Dyin’ to hear what you would all say, but I have to go to bed now – it’s early morning already, huh!

Later,
Mihajlo

Mihajlo, not only did you do a lot of reading, you did a lot of writing too - I'm also off to bed for now, working 12-hour night shifts - I'll try to get to this tomorrow, there's a lot of stuff to cover -

Welcome to the board... Steve

Umh, you thought that was all? Z;->>

Here is my slightly modified floor idea, but the main concept of the '1.5 - 2.5 leaf' wall, holed and slotted is still here... Hope this makes visual sense - I spent the whole day drawing it Well, it was a nice Corel practice session - might need it for the REAL plans, he, he...

C'mon all, shoot me, hang me... or I will be on my way to the Patents office Monday morning, hmm?

Steve, thanks for the welcome!

Regards,
Mihajlo

First, been doing this too long to EVER think the first post has even a small percentage of points covered -

Second (and third, fourth, etc) I'm just heading to work so no time to explain, but you have several inherent problems with that design - too many leaves in wall, too many absorbers in floor structure, too weak covering for walking on drywall material, possible a few others - I'll go deeper tomorrow. The lintels could be a good idea, they just need to be part of the "sprung" weight... Steve

I’m looking forward to your reply Steve. I did warn you that some of these ideas are "off the wall" .
Mihajlo

Attached is the SAE basic floating floor. How well does this do the job? If I would replace the 100x50mm joists with concrete lintels, using construction glue to join concrete and plywood? Nothing bets concrete in price-weight performance . And, how about the sandwich of fibre ‘softboard’ and polyester wool on the bottom? I just can’t stand the idea of any mineral/glass/asbestos wool

Mihajlo

The SAE floated floors are fine, the heavier the top layers total the better the isolation - you need to calculate the total sprung weight against the surface area of rubber (don't use neoprene if you can get EPDM, there's about a 2.5 X difference in lifespan) - don't use TWO of these per point, that lets the concrete lintels act as a separate, flexibly suspended mass and won't damp the upper floor layers. You just want the lower pad for each point. Check out the floated floor link under Reference, near the top of the construction forum for more on a method to determine contact ratio for an ideal of around 20% deflection of the rubber.

Before I can comment on your wall plan, I need you to add to your drawing ALL existing construction in walls, from the outdoors inward, in enough detail so I could actually BUILD it from your sketch -

I also need a sketch of what you're referring to as a "double brick" wall - this could either mean two courses of brick with no air gap, or two brick walls separated by air. Big difference...

Not sure on the polyester wool - do you by any chance have a link or pix or more thorough description?

You've also not mentioned what the ambient noise levels are around your garage, or whether you play with real drums or electronic ones, marshall stacks for amps or acoustic guitars, whether your neighbors exist at all, or are really picky, or are part of the band... Without these details, it's impossible to say how much isolation you need. Security is another possible issue - some types of construction that are good for sound are NOT so good to keep people from helping themselves to your gear -

More details on everything will help us work these things out... Steve

Hi Steve,
Apologies for the late reply – Monday is the busiest day of the week for me… Here goes the plan. I hope this is it?

The main objective is not having to ‘handle’ the neighbours, ever! They are not very close, say 30m to west/east (left/right on the diagram). My house is another 20m to ‘South’ (bottom of diagram). ‘North’ neighbour is in another country , +-100m. Part of this objective is the possibility to use the practice room almost at any time, any day. We are not loud at all – main problem is the bass, as always. We use one of two drummers we have available at the moment, going by the names of Yamaha and Roland, so they are perfectly reasonable and controllable . But, we are planning on having a human drummer eventually, even though that might not be the smartest thing to do ;->

Second main objective is that the space is human-friendly so that we can have prolonged practice session, summer to winter.

HVAC is a highly desirable option, but I am completely lost there… Window-unit pumping into the main garage space doesn’t seem like a good idea because the area just can’t be kept clean… Split-unit mounted on the ‘West’ wall with the pump on the outside of the garage – would that bring any fresh air in?

Thanks,
Mihajlo

you never know how well an assembly will work until you test it. On first glance I think that the idea of drilling all those holes is a bad one. Nobody really considers a slot resonator a leaf because it has all those holes. Remember sound LOVES a path of least resistance I think when it is done you will have a wall that will perform very much like a single leaf of two layers of drywall.

Nice first drawing - only please trim the un-used space and size them so they are no wider than 800 pixels, max - otherwise, they cause un-ending scrolling from side to side, in order to read each line of text. I resized yours, but it's time consuming and I'm never going to have enough time to waste much of it -

Innovations gave you good advice; doing experimental things like extra septums with random holes is fine if you have lots of time and money and curiosity, but if you're on a budget and want to stop building and PLAY, it's better to stick to proven designs.

I think you need to re-read the reference material to see where your ideas will get you into trouble with the neighbors - what you want for best isolation is really much simpler than most people try to make it. All you want is this: from one area to the next, when you don't want sound to get through - put up a heavy mass, such as 4" of concrete, 2 or 3 layers of gypsum, etc - follow that with a filling of insulation, NOT closed cell foam but either compressed fiberglass or rockwool - follow that with a SECOND heavy mass, such as brick, concrete, gypsum, etc - any OTHER materials, if necessary for weather protection, etc, MUST be fastened to one or the other of these two masses WITHOUT any more AIR or insulation spaces, or else you will WORSEN the isolation other than a bit of improvement in midrange performance.

Since BASS is the universal largest problem, you do NOT want to deviate from this formula - mass, air(insulation), mass. Period. No extra air gaps, or you can lose as much as 10 dB, sometimes even more, at lower frequencies.

I posted a concept drawing of this a while back, it's down the page a bit -

http://www.johnlsayers.com/phpBB2/viewt ... 5478#15478

The drawing is for a two room setup, but the concept is the same. Here is another informative page, showing at the bottom several different configurations of gypsum and stud walls - note particularly that the 40 dB wall and the 63 dB wall have EXACTLY the same amount of material -

http://www.domesticsoundproofing.co.uk/tloss.htm

If I read your drawing correctly, there are several places where you would VIOLATE this mass-air-mass principle - please re-examine your intended construction with this in mind, and let me know if you have more questions on the best way of doing any given part... Steve

knightfly wrote:Nice first drawing - only please trim the un-used space and size them so they are no wider than 800 pixels, max - otherwise, they cause un-ending scrolling from side to side, in order to read each line of text. I resized yours, but it's time consuming and I'm never going to have enough time to waste much of it

My sincerest apologies - I battled to understand why Corel keeps exporting a rather small drawing in such a large size? I still don't understand.

Innovations gave you good advice;

Thanks Innovations!

I think you need to re-read the reference material ...

Most definitely I have re-started already. There is a LOT of 'fine print' that I have missed the first time around. By the way, here is an absolutely precious link that I have not seen before: http://www.isover.com. It has plenty of high level (and quite some detailed) explanations for a newbie like me...

Here is another informative page, showing at the bottom several different configurations of gypsum and stud walls - note particularly that the 40 dB wall and the 63 dB wall have EXACTLY the same amount of material -
http://www.domesticsoundproofing.co.uk/tloss.htm

Oh, yessss... Understood.

If I read your drawing correctly, there are several places where you would VIOLATE this mass-air-mass principle - please re-examine your intended construction with this in mind, and let me know if you have more questions on the best way of doing any given part... Steve

Steve, as you suggested, back to the drawing board (literally). Give me some time (a few more months!) to re-assimilate everything, this time thoroughly.

Thanks again, I’ll be back…
Arnold

(Couldn’t resist… Mihajlo)

Drawing size - if you're on Windows, you can pull your drawing into Paint, click one of the drawing tools, move the mouse over the bottom right corner of the USEFUL drawing area, and look at the two coordinates at the lower right of the screen - remember these two numbers (example; 755, 680) - then, click on Image/Attributes, and enter these two numbers in the two boxes for Width and Height, and click OK - that resizes the pic to eliminate the un-used borders. Save, then post. If the image is STILL wider than about 750-800, you can use Image/stretch and skew, and change the percentages downward. Finally, save as jpg and NOT bitmap, or it will be too large a file for posting.

The Isover site has some good info, but you can duplicate just about everything they talk about for less by using standard building materials (if they're available in your area) - the physics is the same. I did like their explanations for the most part.

Difference between you and Arnold - when YOU come back, I won't be quite as afraid Talk to you later, don't hesitate to ask questions if any of the available material isn't clear enough... Steve