Missing a few things: My apologies, I have updated my profile. I am from the Chicago suburb of South Holland IL. USA.
Excellent! That's what was missing.
My goal is to help bands that can't afford much, from recording all the way to mastering. I want to do charity for church bands, and poor people to crate demos.
That's an excellent and laudable goal. I'm a church man myself: I've been running live sound for churches since as far back as I can remember, all the way to early childhood, "helping" my dad twist the knobs and flip the switches on his ancient reel-to-reel deck, which served as the entire sound system. I also teach seminars to churches on how to do sound right. So I certainly understand where you are coming from: Been there, done that, still doing it. I have also recorded some albums pro-bono, or nearly so, and provided plenty of recording/mixing/mastering/acoustic tips for Christian musicians.
I feel for what you are trying to do, 100%.
However, even though my time is my own to give away for free, the equipment I use has a cost: The better quality it is, the more it costs. Tracking well, even for non-professional musicians who can't afford big-name pro studios, still has a cost. You can't do it with a US$ 5 mic that you picked up in a toy store! You can't use cheap a cheap, battered guitar with ten-year-old nylon strings! You can't use a practice electric guitar amp that you found on the junk heap! If you want to make quality recordings, you need quality gear. Then comes the mixing: You can't do it on the tiny little junk PC speakers that you found covered in dust ad bird droppings at a garage sale. You need quality speakers that have flat response across the spectrum you are dealing with. Even more so for mastering. You probably already understand all of the above, to a greater or lesser extent, and I'm sure (or at least hope!) that you have invested in the best possible mics you can find, and the best possible studio monitors you can find. If you don't at least have those two, then there's no chance of achieving what you want. But assuming that you do have those, that's still not enough.
The best mic in the world, placed in a room with lousy acoustics, will sound lousy. Even if you use it close-mic the instruments, it still won't sound the way it should. If the room is "boomy", then everything you record will have a hint of "boomy" in it, no matter how hard you try to EQ that. If the room is "harsh", then ditto: everything will sound harsh. If the room has a sizzling flutter echo in the high mids, then the mics will grab that too, and it will be in all your tracks, no matter how much you try to drown it with canned reverb, delays, or whatever. This is like making soup: if you put too much salt in at the start, it will be too salty always! Even if you add garlic and onions and carrots and whatever, there will always be that underlying sensation that it has too much salt, and there's nothing you can do to get rid of that. Therefore, the tracking room needs to have the right acoustic response that allows the instruments to sound good in the room, and on the mics. And just like you can't record a great vocal on a five dollar mic, so too you cannot get good acoustics on a five dollar budget. Even though your goal of providing a recording space very cheap for Christian musicians who have no money, is very admirable, and very laudable, there's still the basic fact that getting a room to sound good for tracking will cost you money, just as a closet full of great mics will cost you money, and a peair of great mastering speakers will cost you money.
And in the same manner, you already know that you'll never get a good instrument track if you don't know where to put the mics on the instrument and in the room: It takes a lot of study and practice and research to know just how to set up the mics on a drum kit, to capture a set of tracks that really sounds like a drum kit in the mix! You need to have a deep understanding of how condenser mics work, and ribbon mics, and dynamic mics, and boundary effect mics, and shotgun mics, what their polar patterns are, what their frequency response is like, when to use each one, when NOT to use each one, what instruments will work best with each mic type, where to put it, how to orient it, how to arrange several mics together to capture the full sound of the instrument, etc, etc. You already know this, I'm sure, so you know that it's not something you can figure out in a few minutes, or learn overnight, or get right from a couple of "experiments". Good mic placement comes from understanding instruments, and understanding mics, and understating music. It takes time to learn how to do it. You will never get good sounding tracks if you don't do the research and study to understand all of this
In the same way, you will never get good room acoustics if you don't do the research and study to understand how sound works, how treatment works, where to use what type of treatment, why, how, what goal can be achieved in what ways with various types of treatment, etc. You need to understand acoustics deeply, just as you understand mics and instruments deeply already.
The fact that you want to offer your services free, or at low cost, or charitably, is great, but is also irrelevant. There will be an unavoidable cost in materials and workmanship, just as there is an unavoidable cost in mics, speakers, amps, and instruments. The higher quality results you aim for, the higher the cost will be. You can't by a U47 for ten bucks, and you can't by great Fender or Gibson or Marshall for ten bucks, and you can't buy great isolation or great room treatment for ten bucks either! Many musicians and sound engineers make the mistake of thinking that the room doesn't matter: with a great guitar and a great mic, you can always get a great recording. Wrong. The room matter, and it matters greatly. In fact, I'd go so far as to say that in a great room, you can get very decent recordings with a not-so-great mic. Believe it or not, I've done some vary acceptable electric guitar recordings and even drum recordings, using nothing more than a few humble SM-58's, carefully placed in a a great room. But even the best setup with 414's and U47's on a drum kit in a lousy room, is going to be lousy.
That's my long and winding preamble that leads me to your solution: You need quality acoustics in your room to achieve what you want to achieve, regardless of your goal of charitable service, and you can't get quality acoustics without researching, studying, and paying the price that needs to be paid.
That might not sound like a very useful statement, but read it again a few times, and repeat it in your head, until you get it.
Stated another way: Christian churches are big on teaching charity, yes, but they are also big on teaching good stewardship. Use the gifts and talents that you have been given wisely. This might come across as harsh, but blindly buying up thousands of square feet of drywall and hundreds of cubic feet of unknown insulation, just so you can experiment with it, hoping it might do something, is not good stewardship. I'm glad you have the money to do that, because that amount of drywall and insulation doesn't come cheap, but to be very honest, it is all wasted money. You have bought stuff that won't do what you are hoping it will do, as Greg has already pointed out. And you have NOT bought the stuff that you WILL be needing in order to get to your goal.
I would strongly suggest that you should return that drywall and all the other building materials for a full refund, then put the money in the bank on fixed deposit (remember the Biblical account of they guys given 1 talent, 2 talents and 5 talents....), and leave it there until you have completed the research, study, and design of your studio, properly and completely. Then use that money to buy what you will ACTUALLY need to do the job.
I know electronics, and IMHO know how to mix and OK for mastering, but the sound treatment is not my strong suit and I am requesting help.
Great! Then you fully understand that everything I said above is true and correct. And you are in the right place for help. But as Greg mentioned, the forum is more like an "assisted self-help" place: you still need to do the basic groundwork yourself, come up with a plan for your studio that is based on the principles of acoustics, post it here, and we'll be more than happy to help you refine that plan, to make it workable. On the other hand, if you don't have the time or inclination to do the months of research that you will nee to do, and the months of design work that you will need to do, then you should consider hiring someone to do the design for you. Yes, it will cost you money, but probably not as much as you think. And it will save you time AND money in the long run. Plus, you'll end up with a great studio that does everything you need, where you will be able to offer your charitable recording/mixing/mastering services to the best of your ability.
I sectioned off 5.5'x24', where I and the band members are at while recording. The actual recording occurs in the 24'x16' space.
Just like Greg, I'm having trouble understanding that: Are you recording in both places at once? The long, narrow 24x5 space, and also the much larger 24x16 space? If you are only recording in the 24x16 space, then why are the musicians on the 24x5 space while the recording is going on? I don't get what you are trying to say here.
The dimensions don't add up perfectly as there are double 2x4 walls separated by 1" gap on the outside walls.
That doesn't make sense either. It appears that there's misunderstanding of how isolation works. If you have the outside walls of the garage itself, then " double 2x4 walls " within the garage, you have a three-leaf system which is not good for isolation. 3-leaf walls are lousy for low frequency isolation.
Please provide a detailed diagram if what you actually have there, and photos, so that we can better understand your situation, and help you fix it.
The sectioned off 5.5'x24' space also has a double door airlock space to the outside world. No windows anywhere.
Once again, that doesn't make a lot of sense, and is not the way sound locks are supposed to be built.
Q: Define the purpose of your room. What do you plan to do in there?
A: Record bands in the larger space 24'x16'.
Mix and eventually master in the same larger space after the band departs.
That's a problem A BIG problem! The acoustic response that you need for a live room, to successfully track instruments and vocals, is VERY different from the acoustics response that a room needs to mix well, which is also different from the acoustic response that a true mastering room needs. You have steeply conflicting requirements here: If the room is treated to make it a great place for tracking, it will be terrible for mixing, and even worse for mastering. If it is treated to be perfect for mastering, then it will also be good for mixing, but really, really bad for tracking.
There is a solution: variable acoustics. It is possible to build variable acoustic devices on the walls, that you an open, close, swing, rotate, slide, flip, or otherwise physically change in some way, to change the acoustic response of the room. When you set all of those devices to one configuration, the room will be fine for mixing, and when you set them to another configuration, it will be fine for tracking. Here's an example of such a device that I designed for one of my customers a few years ago:
Variable-acoustic-01--panels--construction--half-open-SML.jpg
Variable-acoustic-02--panels--construction--fully-open--SML-ENH.JPG
Variable-acoustic-04--room--completed--SML-ENH.jpg
You would need several devices around the room to be able to get enough change. The device above would not be suitable for what you need: that was designed specifically for a large isolation booth, to provide some variability for dealing with different instruments and vocals. Yours would be very different, but those photos illustrate the concept.
There are several other conflicting requirements for using one single room for both purposes, which you will also have to address in your design, but that's one of the big issues.
Q: Define your isolation. How much isolation do you need, in decibels, to the outside world
A: As much as possible, that is affordable, and is value added for charity. Does 50dB sound reasonable for road noise?
As Greg mentioned, 50 dB is achievable, and is a realistic goal. Take a look at the corner control room thread that I linked you to in my previous reply: he gets a bit over 50 dB. I originally designed his studio for 55 dB, but he wanted to have operable windows, and didn't mind taking a small hit on isolation for that. Even with those windows, he still gets over 50 dB.
However, road noise is a different issue: You should look into that carefully. Road noise has two components: airborne, and ground-borne. The airborne part is the noise that comes to you through the air, from the vehicles on the road to the walls and roof of your garage, then gets inside through those. Ground-borne is a different thing entirely: it is the low-frequency "rumble" that is transmitted through the ground itself, in the form of vibrations that travel through the ground, then into the structure of the studio. If you have a problem with ground-borne noise, that's a much more complex issue to solve. It is far more pervasive, because it causes the entire building to vibrate, and isolating that is not easy. It can be done, yes, but it's complicated. You can do a simple test to find out if you have that type of ground-borne, structure-borne sound: borrow a stethoscope and use that to listen the the concrete slab. Hopefully you have a friend who is a doctor or nurse, or maybe there's someone in the church congregations who is: ask them if they could lend you a good quality stethoscope, and use that (carefully! Don't damage it!) Place it directly on a clean, smooth section of the slab, when there is heavy traffic on the road outside, and see if you can hear the traffic "rumble" in the slab itself. Do the same on the studs, and n the joists. I'm really hoping that there is no discernible structure-borne sound! If there is, then I have sad news for you: you are going to need a lot more money to deal with that.
I can hear the traffic on sensitive condenser microphones, about -50db down. This has me concerned.
Yes. And rightfully so! That's the type of sound that you can't get out of the mix once it is in. "Salty soup" again. You can EQ to reduce it, but that changes the sound of the instrument or vocal. You can try to gate it, or put an expander on it, but that can produce "pumping" artifacts, and the sound will still be there, underlying the music. You can try to drown it with effects boxes, and that an work to a certain extent too, but it doesn't fix the actually PROBLEM: it merely disguises it.
On the inside walls, I am planning on increasing the existing one layer to six layers of 5/8" drywall.
As Greg already pointed out, that will not work. You might disagree, and think "How can these guys say that six layers of drywall will not isolate the room? They must be really dumb!" But the science is clear. For single-leaf walls (which yours basically is, as Greg explained), there is an equation called "Mass Law" that defines how much isolation you will get from mass alone. It's a very simple equation, and goes like this:
TL = 14.5 log M + 23 dB
Where: M = Surface Mass in lb/ft2
Do the math: A single sheet of drywall has a surface density of around 2 lb/ft2, so that will get you roughly (14.5 x log(2) +23) =27 dB of isolation. Six layers will get you (14.5 x log(2*6) +23) = 38 dB. So all your hard work, and huge investment, and large amount of lost space, will gain you about 10 decibels of isolation, and you will still be way short of your 50 dB goal. Mass law says that you would need about FIFTY layers of drywall to get that amount of isolation.
Yup. Acoustics is not intuitive, and there are many surprising things that pop up, when you least expect them. Mass law is not just a mathematically interesting equation: it is a very good representation of what really happens in the real world.
Now, if you were to use only a third of that drywall, making a proper two-leaf wall that has two layers of drywall on each leaf, with Green Glue, and a decent air gap that is filled with good insulation, then you could, indeed, get 50 dB of isolation. Because two-leaf walls are not subject to mass law alone: they are also subject to the laws of resonance, which changes everything. Different ball-game entirely.
I have already purchased enough drywall and green glue to do six layers total of 5/8" drywall.
As I said before return that for a full refund while you can, save the money in the bank, earning interest for the many months that you will need to learn acoustics and do the complete design, then take some of that money out and use it to buy the materials that you will ACTUALLY need, to get the job done right.
Charity is what I have, and the space is what I have.
As I explained at the start of this post, in my long-winded, rambling, meanderings manner: charity is wonderful, and laudable, and excellent, but it won't get you what you need to do the job you want. The building materials and sound waves have no concept of "charity", and won't perform any different just because you are doing charitable tracking and charitable mixing: they will perform the same for you as for everyone else. Drywall won't block sound better because it admires you charitable efforts: it will still work just the same.
Regarding the space: Yes, it is what you have, but it can be modified. It is feasible to take down some or all of what you have already built, doing so carefully so you can recover the materials, then re-build it the correct way. So the space is what it is, yes, but it CAN be changed. This is not a matter of physical limitations, but rather a matter of willingness, embarrassment, and perhaps pride.
I can completely remove the dry wall ceiling, and gain about 4 more foot height peak of a trapezoidal roof.
That's a possibility yes, but only in combination with also removing the walls and starting again (assuming they have been built incorrectly, which seems to be the case).
Should I remove the ceiling and raise to the roof rafters? I will if it makes a difference. Or is the space not useable?
Perhaps the first law of small-room acoustics should be "maximize volume". Getting the greatest possible air volume in the room is one of the bet things you can do to improve the acoustics response of a small room. Especially if it is a tracking room. Having a higher ceiling in a tracking room is also a very, very good thing: the higher, the better. The only problem here would be how to deal with the issue of isolation: there are certainly joists up there that the current ceiling is nailed to, and those are likely part of the trusses that hold up the roof. You need to "get rid of" those joists so you can raise your inner-leaf ceiling, but you cannot do that if they are part of the trusses! But what COULD be done, is to modify your trusses to convert them into "raised tie" or "collar tie" trusses, where the joists are replaced by structural members further up each truss. That's is feasible, but requires the skills of a structural engineer to figure out where to put the new ties, and what size lumber to use, before taking out the joists. DO NOT TRY THIS ON YOUR OWN! Hire an engineer to do it. That would probably allow you to raise the inner-leaf ceiling by several inches, maybe even a couple of feet, best case. That is very worthwhile acoustically. I have done that for the studios of a few of my customers, and it woks. But ALWAYS with the consulting advice of a qualified structural engineer.
It appears I should solve this before anything else.
Maybe, but the ceiling is only PART of the issue. You need to stop thinking about your studio as a bunch of separate walls, frames, drywall, insulation, doors, etc., and start thinking about it as a complete tuned system. All of the parts work together in a totally different manner from the way each of them works by itself. Just fixing the ceiling will not do anything to fix the overall isolation, nor the overall acoustic response. It will help, yes, but it's only one part of the entire solution.
- Stuart -
Decide what initial treatment you will need to deal with the largest issues in the room: design it following the usual procedures and calcualtions, install it, then measure the response again to see if it is working OK.