Preparing drawings for studio. Please check out.

[Hummarstra]

Hi everybody. I've been working on some drawings of basic studio consruction. Now I now these are redundant and have already been posted but I just want to make sure I understand the principles and how they might be applied in my situation. I'm moving into a house in two weeks which basement has concrete walls and PLYWOOD-on-joists flooring. Underneath the floor is a foot or two of crawl space. So, it's different from your typical basement. Now, I'm gonna try to post some pics. I hope this works. Here goes.

 

[Hummarstra]

Great. That worked! Now, I didn't include in that drawing that I also have neighbors towards the upper of top direction of the drawing. So, the idea is to have the studio in the corner of the basement that is the furthest away from my neighbors.

Also, since I will have concrete walls on two sides I'm not sure how much construction is needed on those sides. Here's what I'm thinking of doing, but this might be over kill.

 

[Hummarstra]

So, I haven't a good look underneath the floor, yet. AND, I haven't spoken to a structural engineer, yet, but I hope he doesn't tell me I have to hang the walls from the ceiling which is not out of the ordinary in Denver (because of expanding soil, I think?) Anyway, I wonder what might happen with all that space under the floor. Will it act like the inside of a drum?

OK,this might be premature, but since I made this drawing I want to post it. This next one is my attempt at understanding how to soundproof the ceiling above. In this picture, I ask about how to attach walls to floor joists above. Let me know what any of you think. Thanks.

 

[fitZ2]

Hello Hummarstra, your drawings are just fine. However, I have some comments for you.

Your PLAN VIEW shows, among other things, THREE LEAVES, between the two rooms, and your VERTICAL SECTION also shows THREE LEAVES at the exterior wall. Remember, your CONCRETE WALL is one leaf. Take out the wall between the concrete and your interior wall. Also, forget the soundboard. MASS is what you need, and although they call it soundboard.....IT AIN"T
Just substitute another layer of 1/2" drywall between the two layers of 5/8".
Also, take out the center wall between the two rooms. Each room is it's OWN LEAF, with an AIRGAP between them. But here is another thing to check with BID about.

Normally, all walls will have a FIRESTOP block about half way up the wall, in every wall cavity. But in this type of construction, since you have an airgap, there is NOTHING to stop fire from going up the interior of the wall. Now, I'm NO EXPERT, but this MAY be an issue in your location. I have looked on the internet in this regard and some cities allow FIBERGLASS insulation as a firestop between DOUBLE PARALLEL walls, IF YOU FILL THE AIRGAP with insulation at least 16" from the floor upwards. But DON"T TAKE MY WORD on this, as one member here lives in a location where the codes require all EXTERIOR walls to be sheithed on the INTERIOR with drywall. As you have concrete exterior walls, this wouldn't apply I think, however, you need to talk to BID about the applicable codes in your location.
Ok, about the floor. YES, it will act as a drumhead. Again, I'm no expert, but I believe you only have a couple of things you can do about it. ADD mass to it, and add insulation in the JOIST CAVITIES (no fun!!) But this ALL DEPENDS on what the structural engineer AND what the codes require.
BTW, you don't show, or have told me HOW the existing basement floor FRAMING ties in with the CONCRETE WALL. You mentioned the STEEL BEAM in the center, probably running the LONG dimension, but not how or what supports the joists AT THE WALL. AND if there are piers between the steel beam and the wall, which I doubt, but you never know. So, as to your PROPOSED "floating floor", the SECTION drawing looks ok, however, this still depends on the codes and engineers ok. He MUST know exactly what you are planning, and what exists, which I'm sure he will look at. But let me add something here. Some information has come to light in the last week, that you should read.
These "pucks" that "supposidly" decouple the new structure from the existing, are supporting not only the WHOLE ROOM, but equipment and occupants also.
Because of this "loading" on these isolation pads, compression takes place, and from what I understand, now they display a different "resiliancy function"
that may actually change the resonant frequency of the structure itself. Or something to that effect . Because of this compression, shape, spacing, density, "springyness", dampening and other factors must be taken into consideration when specifying these pucks. Because so many people here and elsewhere have built floating floors using "net fact" specification of these "resiliant pads", it has almost become a cliche solution for decoupling floors. But now, because of this new information, I am hesitant to continue offering my opinion regarding how to do this, as I believe it is MUCH more difficult to correctly calculate this stuff than I previously imagined.
Calculations for SPECIFYING these, are VERY VERY difficult and from what I understand, if done incorrectly can actually AMPLIFY some frequencys. Now I won't pretend to know much of anything in this regard. I have read quite a bit, and some of it makes sense, but MOST of it is WAAAAAAAAAAAAAY beyond my abilitys to comprehend. But I DO know this. You ALREADY have a floor that is a DIAPHRAM, which means, it will ALSO affect the NEW structure, as it too has a resonant frequency, AND an airgap which MAY or MAY NOT, ALSO have a resonant frequency IF SEALED. SOooooooooo........
at THIS POINT, it may behoove you to procure some PROFESSIONAL consultation in this regard, as it MAY turn out to be so technically and financially difficult to rectify the situation to achieve your isolation
goals, that it might be better to lower your expectations. In any event, to prevent total failure or disappointment, and wasting time, money and effort, knowledge is the key. This existing floor, Denvers codes, and your isolation requirements are a quagmire that in my opinion, demands Professional expertise.

As to the new walls/existing ceiling joist connection, this is done in two ways that I know of. Either a "decoupled sway braces", or capturing the top edge of the wall in a custom built"channel" with continuous rubber gaskets on
all three faces of the channels interior. This decouples the wall, and blocks the path to sound flanking over the wall. Walls perpendicular to the joists, require decoupled blocking between the joists OVER the wall too. But there are MANY little details such as these to look at when the time comes that all your code and structural conflicts have been resolved. THEN, you can look at all these details.

Well, thats about all I have for you, untill some of these questions are delt with. Good luck, and keep us up informed of your progress.
fitZ

 

[Hummarstra]

FitZ2,
Thanks for the great reply . Firstly, that middle wall in the first drawing was not supposed to be there - I just screwed up. .OK, so what your saying is - and this is very important- is that those two walls of my "hoped for, but yet to be determined" studio that boarder the concrete walls DO NOT NEED a second wall. Not, even where the egress window is (although this will be soundproofed well). If that is the case, this will save me ALOT of cashola. So, I'll just build double walls for the other two sides.

Now, regarding the "FIRESTOP block", I didn't understand in your post which "wall" you were refering to. The concrete wall? One of the walls that I'm gonna build? Could you clarify that?

I don't yet know how the floor joists are connected to the concrete walls. That'll have to wait till I move in.

If the steel beam were pictured it would run from bottom to top along the basement ceiling.

Point well taken regarding the pucks. I think this floor will be particularly problematic.

I've already seen the info on sway brackets. I was just hoping there was an easier way to do this. I guess not.

Well, I'm gonna adjust those drawings and repost them either tonight or tommorow. Again, everything is really just speculative until I get a professional down there to check it out. Thanks again, FitzA

 

[Hummarstra]

OK. I updated the floor plan to include only two leafs all the way around.

 

[Hummarstra]

Here is a new pic of the wall leaf design up close. But, do I insolate the concrete wall, too?

 

[Hummarstra]

Man, I gotta shrink these friggin' pictures, but smartdraw is a pain in the ass.

Well, here's my other question: how do you best soundproof an eggress window.
see below.

 

[fitZ2]

Hello Again. Your plan and sections look correct now. Couple of comments.
Regarding the insulation on the concrete wall. Yes. Two ways to do it. Attatch vertical furring strips to the concrete at 16"oc to provide a fastening point for plastic strapping to hold the batt insulation in place. Use 1x2 even though the insulation is thicker. Or you could simply drive concrete anchors at 16" oc, 4 high evenly spaced, as a tie off for wire. As you place each batt, pull the 4 wires across and wrap around the anchor(leave the anchor sticking out an inch.) You could use rigid fiberglass but it is quite a bit more expensive and you really don't need it here, as I'm sure your acoustic treatments will use quite a bit.

Regarding the floor. You are correct. This IS problematic. I'm sure plenty of people have built studios on existing wood floors. This doesn't mean they are correct, or they understood the implications, or did ANY good whatsoever, or were recording things that had no bearing on the performance of the floor, acoustically, transmission wise, or resonance wise. This subject(two membranes tied by gravity)has not been discussed at length here, but the thread I linked for you did. There are differing opinions, which TELLS me, that it is open to scientific explanation, of which "I" have NONE The moderator(knightfly or Steve) at the construction forum at John Sayers site, has helped many people who have used his advice to build wood floors, although I have yet to see discussion of a "floating wood floor", upon ANOTHER wood MEMBRANE floor. I believe all of these were constructed upon concrete slabs, which rest on grade, and that tells me they behave in a different fashion than a wood membrane floor. Although they still are a "leaf", I would guess, because of the mass, and the mass of the EARTH it has a resonance much lower than your existing floor could EVER attain, no matter how much you add to it. That is the problem. Membranes resonate BACK into the space, and can actually make the situation WORSE. At least from my understanding.
Now, Steve did offer advice to "conan" on a current thread here, who was dealing with a similar situation, although it was on a THIRD floor, which in my mind is the same thing you have, although there is "nobody" below. I too, am helping a friend design a small personal studio, and through Steves help, have decided to build a "floating wood floor", although it will be supported by an existing concrete slab. AND, this floor will ACTUALLY be TWO frames. The first, is like a "deck" frame, that allows for leveling of the "real" floor frame, which CANNOT be leveled in place. Thats because it is a series of modules that consists of 2x6 framing members, and a 3/4" OSB "BOTTOM", that when positioned in place, fastened togeather, a visqueen layer placed within the cavities, and kilndried SAND poured into the cavities, makes it impossible to access the bottom to level it. After filling with sand, another visqueen layer placed on top of the framing and sand, and then TWO layers of OSB screwed over it to form a subfloor. Also, the primary framing provides a substantial AIRGAP of 4", which will be filled with batt insulation. This is another problem with your floor, as your airgap is quite small, which makes for Low frequency transmission loss quite small. That in turn, tells me that, depending on all the other factors, it might not be worth it to float this floor, ESPECIALLY IF the existing floor is NOT touching the concrete walls. That is why I asked you how this existing floor is SUPPORTED, as it MAY have it's OWN support footing. This would make the existing floor an "isolated" membrane, which MIGHT allow your rooms to be built upon it with little structural transmission to the concrete walls. However, this remains to be seen. AND, I am no expert. It is worth considering though, as there MAY be other code and structural limits that force this decision anyway
As to the "egress" window. Does the window have a concrete DAM around it extending into the yard to allow light to enter IF, the window is NOT flush with the interior face of the concrete wall, I would build a 2x4 frame 1/4" smaller than the opening. Cover the exterior side of it with 3/4" water resistant ply, then slip it into the opening, caulk the gaps,fill with insulation, and then fasten 2 layers of water resistant drywall on the interior.
Fasten a 1x2 trim OVER the gaps, and VOILA!!
Well, I'm out of time. Hope this helps. Talk more later.
fitZ

 

[frederic]

While you're putting a lot of effort into proper design and construction, I am curious why you chose to make your rooms rectangular. That is the fastest and easiest way to waste a tremendous amount of money on construction, just to acquire a huge-ass standing wave problem. If you angle the wall between the two rooms in the lower left hand corner of your diagram, you can significantly reduce standing waves and drastically increase the effectiveness of your construction techniques.

Get your money's worth, don't make the rooms rectangular.

 

[Hummarstra]

frederic, yeh, I'm thinking about going with the rectangular perimeter but putting the control room in the middle and making a small vocal booth on one side and a larger room on the other. That'll get rid of the square shaped rooms.

BTW, can someone tell me if I need to put something on those concrete walls? I've gotten conflicting advice on that.

 

[fitZ2]

just to acquire a huge-ass standing wave problem.

frederic, I am under the impression that this is simply a matter or opinion. From what I've read, in authoritative acoustics books, this is one school of thought, yet another says that standing waves(room modes, no?) exist regardless of the shape. I am also under the impression that angled walls are used to direct mid and upper frequency sound waves to the rear of the room so early reflections do not interfere with the engineers ability to hear reflections in the studio over the monitors. Yet, this too has me baffled. If sound travels at approx 1130 ft per second, thats approx 1 millisecond per foot. The ear integrates any difference in sound delays of less than 20 ms. So how can an engineer distingish or hear a reflection off a side wall that is 6 to 8 ft away, as that is less than the time the mind can distinquish the difference. SOMETIMES, I REALLY begin to wonder. I have even read ANOTHER opinion, that stated the BEST monitoring position should be with your back against the rear wall as the time delay between direct and reflected sound behind you is so short, that it is IMPOSSIBLE to hear a difference. So go figure. Lately, with so many opinions, and so little PROOF, I get the feeling it is ALL SNAKE OIL. But you sell it cheaper than anyone, so I'll take a gallon
fitZ

 

[frederic]

There is a lot of theory floating around, true, and a lot of it is correct, at least partially.

A lot of the simpler calculations you can do, are assuming the speakers in the room originate all their sound from a central point within the speaker cone. Then perpendicular off the speaker face, we draw a line, and reflect that line around the room matching reflection angles to determine where its going and what its going to do. Like so:

 

[frederic]

The black line is the fundimental direction, as it will reflect around the room, assuming the speaker cone is absolutely flat (i.e., not a cone) and doesn't deform in any way while it moves.

Since speaker cones are actually cones (and why we call them speaker cones!), there are more lines to be drawn. I've added two red "perimeter lines" and drew the associated reflections for those as well. I've made an assumption here, do you see it? Yes, I've made an assumption that the speaker cone is in fact a cone, and has consistant non deforming sides that are at a constant angle. With these assumptions, you can see the potential for standing waves vertically up and down the left side of the diagram. To be a standing wave, the wave has to amplify itself by overlapping itself perfectly. This is difficult to achieve mathematically, because its possible to have a standing wave between the back wall and the speaker edge, where it overlaps itself, but once the wave comes back and hits the front wall (bottom of diagram), its not going to be in phase on its next reflection, more than likely. You can move the speaker up or down vertically to align the new audio waves with the reflected audio waves, and it would have to be fairly perfect to work.

 

[frederic]

Though what about all the acoustical energy in between the perpendicular line, and the perimeter lines that I've drawn in the above two diagrams?

 

[frederic]

Yeah, start drawing the reflections on those lines And at points where the acoustical energy crosses each other, you have a potential point (of collision) which many things could happen. The acoustical wave could change direction, a primary wave could overpower the colliding reflection, you could have a reduction in volume (db) or an increase in volume, depending on many factors. These are the factors we try to use as a guide for acoustical treatments. Here is some math:

V (sound in air) = 331.4 + .6T meters per second.


T = temperature celcius.

So, after doing all your inaccurate, approximative wave drawings like I have, change the temperature, and its all "way off" anyway. At 70F, sound travels at approximately 1129.5202682997958 feet per second. At 40F, sound travels at approximately 1096.1650627004955 feet per second. At 90F, sound travels at approximately 1151.7570720326625 feet per second.

have a headache yet?

Reflections are how your brain uses the information from your two ears (stereo image) to near-instantly determine your position within a room. Consider this experiment.

I, instruct you Rick, to stand blind folded on a moving dolly. I and Knightfly move you on this dolly around a rectangular basement so slowly, you cannot feel what direction you moved, to different positions within the room. Knightfly will move to another part of the room, and clap his hands once. You, from what you hear only, would be able to guestimate the angle from your nose that the original clap occured, thus identifying approximately his position, from you, within the room. In addition, if you really were to think about it while standing on the dolly, you'd also be able to determine where in the room you are, and how close to which wall you are, north, south, east, west. Thank you Knightfly for your participation.

How would you know this? Locating Knightfly is easy... because the primary source (the actual clap) is going to be louder than any reflection. So you could effectively point at him within a very small margin of error, even though you cannot see him.

Your ears also pick up reflection waves, which is part of how our brains work, and based on the reflections entering your ear canals, you can determine your distance from any of the four walls by comparing reflections. You don't have to actually do this comparison, your brain does it automatically. Your spongy processor is taking into consideration timing differences, as well as amplitude differences to make these determinations. So you can in fact, blindfolded on a dolly, not only point at Knightfly, you can also say "north wall", or "South East corner", etc, with a high degree of accuracy.

Now, when you treat a room, and have fairly significant amplitude generating sound sources (i.e. studio speakers), this changes, because its NOT an environment your brain was designed to decipher. By changing the reflective, and absorbtion properties of the room, you can easily confuse the brain as to location within the room, even though more than likely you could pick out the initial sound source still. The "deadder" the room (meaning more absorbtion), the less likely it is you can define your position within the space, using only your hearing.

Because of the massive energy bass frequencies carry just by the very nature of it, if we were to repeat these tests with a subwoofer in the room, pumping in say, oh, 1200W RMS, you'd never pluck your position out of the room blindfolded, because the energy (pressure waves) in the room would be so great your brain would be confused. Bass is non-directional, because it goes everywhere, and while it does reflect and does bounce all over, having more energy than the air can consistantly transmit introduces all sorts of acoustical problems.

Another anomily of the ear-brain system is the automatic ability to "self-filter" monotonous noises. If you have several consistant, noisy devices in the room, your brain will filter those fundimental frequencies and associated harmonics, out of your perception after a while. Same principle that noise-cancelling headphones use BTW. Anyway, slap a window air conditioner in your room on the left side, and after a period of time you won't hear it the same way any longer. But, because your brain is filtering out that noise (mostly the harmonics actually), its also filtering out acoustical information unrelated to the air conditioner, acoustical information generated from your studio speakers.

take all that into consideration in your math, please

Anyway, all this data, as perceived by the brain, is what gives us as musicians, engineers, hobbiests the ability to "decide" what a room feels like. Is it "dead", is it "warm", is it "smooth and creamy". I had a pro studio years ago, and my partner could be blindfolded, walk into any room, and based on normal speech in that room, tell you what is on the floor, walls and ceilings if the room was "medium sized". Not only could he say "hardwood" if there was, but he could tell you "maple" or "birch" or "oak". Tell me that is not impressive. This is an individual who's very aware of his surroundings, moreso than the average guy.

So, have a headache yet?

A lot of what "sounds good" of course is subjective, but one thing to keep in mind is the acoustical power generated within a space. We often don't touch on that here because it's really difficult to calculate and comprehend, but it does matter greatly.

In a 9' x 11' room, a pair of Radio Shack minimus-7's with a small 8" sub will sound pretty good at reasonable levels, even without a tremendous amount of acoustical treatments. Replace those with a double-15" woofer, 5 speaker setup (per side), drive that with 1000W RMS of crown amplifier, and that room is going to become painful, and the acoustical information your brain picks up is going to be very garbled. You've overpowered the room.

This is another reason why larger rooms sound better than smaller rooms to the majority of people, because its more difficult for a sax player to overpower (acoustically) a room that's 20'x30 with a 14-18' vaulted ceiling. And if you mic closely, you can record that musician fairly dry.

Acoustical power is also the reason why I believe gents like John Sayers recommend using the length of the room rather than the width, so there is more air behind you, rather than in front of you. It gives the primary acoustical energy from your speakers a place to go. As sound travels through air, it loses its amplitude because objects at rest, want to stay at rest, and will resist acoustical energy. Basic physics. And the objects that want to stay at rest in this case are air molecules.

Now, lets discuss the listening position. You mentioned that some "ekspurts" suggest mixing at the back of the room, therefore eliminating the perception of reflections because you're so close to the back wall. In theory, this sounds reasonable. I tried it in a bedroom studio when I lived in connecticut, and I didn't like how it sounded at all. Why? I dunno. I can't really explain why, but it didn't sound too good. It's very possible (and likely, I guess) that because I've owned a few pro studios, and set things up "the other way", I'm used to having air behind me, not in front of me, and out of "brain habit" I wouldn't like it no matter what. Conditioning maybe?

 

[RICK FITZPATRICK]

Then tell me why MILLIONS of records have been sold, that were recorded in studios that were NOT designed with these subjective "acoustical" theorys as the basis for orientation or treatment. I don't think the consumer, especially today, gives a DAMN. In fact, considering current digital signal processing, tracking, mixing, mastering and certain types of music, it appears(at least from what I've heard) that even an EXPERT engineer could NOT tell from a recording, what design dogma, size, configuration, orientation a control room had, or studio treatments, or engineering position, or any other factor that is in current studio design vogue. It also seems to ME, that the ONLY thing that matters to a consumer, is they LIKE the MUSIC. Like my DAD says. "Who the hell cares? If I LIKE it, I LIKE it. Even if it sounds like shit". Also considering some current recordings I've heard that DO sound like shit to me, they are still making the artist and the record company MILLIONS of dollars. So....you tell me? If some BOZO rap artist, with a record player, a shitty mic, a drum machine, and a room the size of a closet, with carpet pad as treatment, can make a record that sells 100k CD's, WHAT IS THE DIFFERENCE? (you don't have to answer, cause I'm just spouting off what I hear)
Let me put it this way. I LOVE Django Reinhardt. I LOVE the sound of those recordings. They were made in the 30's/40's/50's. I wouldn't trade these records for ANYTHING out there today. Yet, they were recorded in different studios, clubs, hotels, homes, etc. Yet ALL the recordings have captured what is IMPORTANT. And this is WHY current recordings, at least to ME, are NOT what recordings USED to stand for. And that is PERFORMANCE. Old recordings used to capture a PERFORMANCE. THAT is what was important. Todays recordings do NOT. They are digital multitracked, overdubbed, over processed and generally over produced FAKES of performance.
That is why my view of current recording studio design is at odds with what I think is important. Current design, seems to influence the view that the "recording" is the ART. Not the performance.

fitZ

 

[frederic]

Very easily explained.

Acoustics, physics and mathematics does not replace talent and good judgement. An untrained monkey using top of the line SSL digital stuff will make a worse recording every time as compared to a talented, industry experienced recording engineer using a $99 portastudio with a radio shack microphone.

That is the component of recording that math, acoustics, and physics does not take into consideration.

 

[RICK FITZPATRICK]

An untrained monkey using top of the line SSL digital stuff will make a worse recording every time as compared to a talented, industry experienced recording engineer using a $99 portastudio with a radio shack microphone.

If that is the case, then why would an "experienced" engineer need the design and layout dogma in the first place?

Not only that, but IF, there is only one design solution that satisfies EVERY engineer, then WHY isn't EVERY studio using it?

 

[frederic]

Lets draw an analogy.

If you, driving a ferrari, were to race Andretti, driving a Yugo, I'd expect Andretti to lap you at least once

But... should we lock guys like Andretti into a yugo when they can afford a Ferrari? Of course not.

While an experienced engineer would make a better recording on a portastudio than an untrained monkey using SSL digitals... picture what the end result would be of an experienced engineer using the SSL stuff instead of a 100 buck portastudio?

The gear and facility is nothing more than a tool. You can buy good tools, or crappy tools.

Since you're into woodworking, which router did you buy? The $99 Home Depot Ryobi with the free router table? Or did you purchase a dewalt? Or a hitachi? Porter-Cable? Bosch? Makita?

Why? Answer why to my router question, and you'll have the same answer for why any studio owner would spend any time or money making a better facility.