John Sayers' Recording Studio Design Forum Archive

I recently purchased a house with an unfinished basement of about 1250 square feet. I plan on using a portion of this basement to build a new studio. I have built 6 studios in the past ranging from very simple one-room studios to full multi-room commercial studios. I have always struggled with the decision of whether to simply build rooms with surface-mounted acoustic treatment added to standard drywall walls for easy resale later (all my studios have been built into various homes I have owned), or building the acoustic treatment more into the structure itself — fabric covered walls, etc.

For the most part I have always made the decision to go with the more "standard" construction so when I sell a home, I can take down all the acoustic treatment and it will look more-or-less like a normal room. I still have done construction methods such as double-walled construction for isolation, angled walls to minimize flutter, etc. But those types of additions are still easy to look "normal" once the studio has been removed from the space.

Regardless, I am in the position again to decide on which method to go with again. I am leaning towards the same type of construction I've done in the past. So I wanted to post here and see if anyone has any thoughts on maximizing a build that uses more surface-mount type methods.

First, this studio is in a completely dug-in basement. There is no walk-out, window wells, etc. So my concern about noise either going out or coming in are not really a concern. There's no issue with neighbors. I also don't care about noise going upstairs either as it's my home and I won't be bothering anyone up there. So really, my main goal is to make the acoustics great in the actual rooms of the studio. Of course, I will have isolation between the control room and live room via a mass-air-mass double wall. I won't do a M-A-M wall with the vocal booth though due to space, as well as the fact that I rarely use both the live room and the booth at the same time. I probably will do a 2x6 staggered stud wall though for the vocal booth as well as the back wall of the control room. At least this increases the isolation without eating up too much extra space. And I simply don't need the isolation from the control room to an extra living room on the other side.

Attached are several pictures of the basement as it sits existing, as well as what I am planning. There is one labeled "Splayed Walls" which is part of a question I have on what will be best for this room. I have also included a Sketchup file.

All acoustic treatment that can be seen in the 3D pictures will be framed, 703-type fill, and fabric covered panels. Some 4" thick. Corners and ceiling/wall junction bass traps will thicker or solid, mega traps. I haven't added any diffusion to the 3D renderings, but there will obviously be some on the back wall of the control room, as well as some scattered throughout the live room.

The image labeled "Splayed Walls" shows 2x4 furred out walls from the perimeter concrete walls. These are already in place around the entire outer structure of the basement with insulation already in the studs. I imagine a wall like the front of the control room will be left un-drywalled. In place of drywall, wood paneling left open with various height slots left open to the insulation behind. This method could also be used in the live room and vocal booth as well if needed.

Of course, I am open to any alternative layouts and ideas as well. This is just kind go where I'm headed due to the natural shape of the basement and the main beam that runs through the middle as pictured in the Existing Basement renderings. But if there are some obvious layout ideas that I am missing, I am all eyes and ears.

As far as budget, probably between $10,000 - $15,000 for the build. Not the whole basement, just the studio portion. Flooring doesn't have to be included in that as that will be done separately.

Note: Ceilings are 8'4".

Basically, my questions are:

1) Since I don't plan on hard or soft soffiting my speakers, would it be better to use have the control room side walls be straight as showed in the 3D renderings? Or would it be better to splay them inwards towards the front of the control room as pictured in the image labeled "Splayed Walls"? The reason I'm thinking the splaying would be better is because I do have the large window to the live room on the side of the mix position. All rooms I have built before have had the window in the front. I have been able to always install absorption in the first reflection points with the window in the front. But since the window will be on just one side with no possibility of absorption, will the splaying solve the issue of not being able to treat the window area on the right side of the mix position while still treating the other side?

2) Will the type of treatment I have shown in the renderings be enough for the rooms? Rooms I have built in the past have been similar treatment and I have been perfectly happy with them. But if there is something I can do on this build to take it up a notch, I am happy to listen. Ceiling panels are not shown in the drawing but would be installed as well (control room cloud, live room ceiling panels, etc).

3) Are there too many parallel walls in the live room? If I had to, I could angle one of the large main walls. I just don't want to eat up any more space than I have to though. In the image labeled "Splayed Walls", I have some angled traps around the room. Will that type of wood/slot panels be enough to break up any parallel walls?

4) Anything else I am missing?

Thank you in advance for the assistance. And please let me know if I have left any details out or missed anything.

Sketchup File

Hi there " rainmaker", and welcome BACK! It's been practically ten years since your last post!!

an unfinished basement of about 1250 square feet. ... Ceilings are 8'4".

That's a pretty decent space, especially the few inches of extra ceiling height. Is that measured to the bottom edge of the joists?

So I wanted to post here and see if anyone has any thoughts on maximizing a build that uses more surface-mount type methods.

There's basically two ways of approaching room tuning. One is to start with a disgustingly over-live, resonant, reverberant room, with all solid surfaces around it, then hang bits and pieces of treatment to tone it down, take it, and get it to behave the way you want. That's the approach you have taken so far. The other is to start with a disgustingly dead, lifeless, disturbingly morbid room, with all absorbent/diffusive surfaces, then add bits and pieces of treatment to liven it up, put some feeling and motion into it, and get it to behave the way you want. That's the way I normally go about it. Both methods are valid, and both work, but I have me reasons for preferring the "kill-it-then-revive-it" approach, rather than the "hype-it-on-LSD-and-cocaine-then-strangle-it-slowly" approach...

One of those reasons is that with the "LSD-and-strangle" approach, you have to start out with smooth, massive, rigid, surfaces all around the room, then on top of that, you hang protruding chunks and hunks that poke out at out. Whereas with the "murder-then-resuscitate" method, you have to start out with all soft surfaces: the entire room normally is just insulation and studs facing you, so anything you add on top of that to liven it up, is going to become your final finish surface, and those will all be flush with each other, for the most part: nothing poking out.

Another reason is finer control: You can add one slat at a time to a slot wall, and watch the miniscule changes on the graphs slowly approach what you are looking for, at a snails pace, until you get there. With the "LSD" method, you normally hang huge chunky things, rather than a whole bunch of little things, because huge chunky things are far more effective, and easier/cheaper to make.

Etc.

And just to confuse the hell out of you, sometimes I do both at once! Here's a case where that happened: http://www.johnlsayers.com/phpBB2/viewt ... =2&t=20471 When I came on board as "fixer-designer" ( ! ), the basic shell of that room was already in place, with no chance to change it. So I killed the front wall and ceiling, with massive absorption, then brought them back to life with various things, while at the same time I hung "huge chunky things" on the side walls and rear, to deal with the issues that were happening there. But even those "huge chunk things" (don't you just love my accurate use of acoustic terminology today? ) were carefully tuned. Some of those side wall modules have three entirely different sections in them, doing a bunch of different things at once. They look like plain old absorber panels, but there's some magic hidden behind that face fabric.

OK, so I guess the above is not really the answer you were looking for, since it is sort of a "Yes, no, and maybe" answer! ... But it does give you some things to think about. And personally, I'll usually go with the "murder then revive" system, since I like the way it works out, and the degree of control it gives me.

I also don't care about noise going upstairs either

Have you considered noise coming the other way? Thunder, rain, hail, wind, aircraft, traffic outside, with the noise getting through to your mics? Washing machines, vacuum cleaner, phone, TV, radio, toilet flushing, HVAC system running, water in pipes, people talking, walking, doors opening and closing? Nothing like that could happen while you are in a session?

Of course, I will have isolation between the control room and live room via a mass-air-mass double wall.

Unfortunately, that won't work. Isolating just one wall of a studio is pretty much the same as trying to build an aquarium by putting glass in only one side of the frame... after all, you only plan to look at the fish from that side, so that's the only side where you need to stop the water running out! I think you get the point. Unless you isolate all sides of the room to the same level, you don't get isolation. Sound will "flank" around your fantastic wall, by taking the weakest path through one of the other walls, the ceiling, the floor, the HVAC system, the electrical system, etc. Isolating a room is an "all or nothing" proposition.

That does not mean that you have to build a completely separate stud frame around the entire room to get more isolation, but it does mean that you need to decouple the leaves on all sides, and add sufficient mass. The key is to get the MSM resonant frequency down an octave lower than the lowest note you need to isolate, and there are a couple of things you can do to attain that.

I won't do a M-A-M wall with the vocal booth though due to space, as well as the fact that I rarely use both the live room and the booth at the same time.

Once again: noises from outside? Above? The rest of the basement? Never going to be a problem?

I won't do a M-A-M wall with the vocal booth though due to space, as well as the fact that I rarely use both the live room and the booth at the same time. I probably will do a 2x6 staggered stud wall though for the vocal booth

Ummmm.... Actually, a staggered-stud wall IS a MAM (or "MSM") wall!

as well as the back wall of the control room.

Same as above: isolating one wall alone does not accomplish much.

At least this increases the isolation without eating up too much extra space.

Actually, there are ways to get even more isolation while taking up even less space....

And I simply don't need the isolation from the control room to an extra living room on the other side.

Thinking about isolation in terms of "this side" and "that side" is not the right approach, since there are no "sides" to isolation, other than "inside" and "outside" the room. If you have a room where three walls and the ceiling are isolated to 40 dB, and the other wall is isolated to 60 dB, then the total isolation is very much closer to 40 dB than it is to 60. The time, effort, materials, and money spent on doing that one wall to a high level, are mostly wasted. It would have been better to spend the same money to do all the walls and the ceiling to just 50 dB, as the result would have been far better.

The big problem is "flanking". Sound is like water; it takes the easy path out of the room. If you have a small stream running along merrily through the country side, and you dump a huge chunk of concrete in the middle of that stream, the water will just go around it. You will have created a very small local effect in the flow, exactly where the concrete is, but overall, you will not have affected the stream at all. It still flows.

Corners and ceiling/wall junction bass traps will thicker or solid, mega traps.

Not sure I understand what you mean by a "solid" bass trap. Bass traps can't be solid! They should also not have "thicker" absorption than what you'd use in first-reflection point absorber, or ceiling cloud: for a bass trap, you need lighter (less dense) absorption for low frequencies, not heavier. And I'm very curios about your "solid" bass trap.... if it is solid, then it can't be much of a bass trap!

I haven't added any diffusion to the 3D renderings, but there will obviously be some on the back wall of the control room,

Right. Your CR is, indeed, large enough to be able to use numerically-based diffusion on the rear wall (barely!), but you will also need substantial absorption on that wall, even on the back of the door.

The image labeled "Splayed Walls" shows 2x4 furred out walls from the perimeter concrete walls. These are already in place around the entire outer structure of the basement

Why? What's the purpose of making your room so much smaller by furring out 2x4s directly attached to the outer-leaf? It almost sounds like you are thinking of going the "kill it the revive it" method like that...

But I'm a little confused: you are asking if splayed walls are a good idea, but you are also saying that they are already in place! ? So if the answer is "No, bad idea", then you would be happy to tear those down?

I imagine a wall like the front of the control room will be left un-drywalled.

This is really confusing: a splayed wall that does not have a leaf on it, is not a splayed wall! It's just a frame with "stuff" on it. It will not affect the modal distribution of the room, which seems to be what you are concerned about, and it won't create an RFZ or CID concept either.

In place of drywall, wood paneling left open with various height slots left open to the insulation behind.

You mean like a slot wall? A tuned array of Helmholtz resonators, that selectively modify the frequency, phase, and timing of the sound field? Right in between the speakers and your ears? That might not be a good idea...

This method could also be used in the live room and vocal booth as well if needed.

Yes, definitely, for the LR. No argument.

1) Since I don't plan on hard or soft soffiting my speakers,

Is there any reason why you don't want to soffit-mount them? In my opinion, for what that's worth, it's probably the single biggest thing you can do to your room to greatly improve the acoustics, as well as improving the response and loading on your speakers. It eliminates many of the big issues that affect rooms where the speakers are just out in the open. (By the way, a "soft" soffit is not a soffit at all! I've seen that myth bandied about before, but it just isn't. All it is, is a speaker embedded in absorption. In order for a soffit to work, it MUST have a very, hard, solid, very massive front baffle. No baffle = no soffit).

would it be better to use have the control room side walls be straight as showed in the 3D renderings?

If you are not going to soffit-mount, and therefore won't be maximizing acoustic response, then you could go with a simple rectangular room and more treatment. Splaying the walls doesn't do much either way, if the angle is small. For a true RFZ room with soffits, the splay angle is rather large.... but it only affects a small section of the side walls at the front, nowhere near as much as you show. If you aren't doing RFZ, then splaying is just a waste of space, in my opinion. Reducing room volume for no useful purpose doesn't seem useful.

And speaking of speaker: ... what speakers are you planning on using in there?

Or would it be better to splay them inwards towards the front of the control room as pictured in the image labeled "Splayed Walls"? The reason I'm thinking the splaying would be better is because I do have the large window to the live room on the side of the mix position.

Then splay the window....

There's no law that says you have to keep the glass parallel to the surface of the wall. You can make the wall thicker, and angle the glass a bit, if you are concerned about reflections. I have done that in a couple of rooms. It works, as long as you do your ray tracing carefully, to make sure that you really are moving the reflections far enough.

You didn't show the location of your speakers in the diagrams, so it's hard to say if the glass will be at a reflection point or not, but I do have to say that the entire front end of the room does not appear to be laid out optimally. The chair and desk appear to be far too close to the front wall, with no room to fit the speaker stands in, nor to set up the correct geometry. I realize that this is just an early draft, but since you are asking about reflections to the mix position, it would be good to fix that, and get all of your front-end layout done correctly in your model, so we can actually see where things will be.

will the splaying solve the issue of not being able to treat the window area on the right

It's not clear what your plan is with the splaying, so it's not possible to answer that question. If you want the splayed walls to be highly reflective, such that the act like walls in the RFZ, CID or NER concepts, then yes, that could work... but your window will still be there, at the first reflection point! However, if you are talking about building your splayed walls as some type of treatment device, then no, it won't be much use for dealing with first reflections.

2) Will the type of treatment I have shown in the renderings be enough for the rooms?

Probably not. It's a small room, so it will need large bass traps. It will also need enough overall absorption with the right coefficient to attain the correct decay time for a room with that volume. That will set your Schroeder frequency, which will help you determine what other treatment is needed, and where it is needed. Tuning a room is a process.

What decay time are you aiming for, for this room? What's your goal?

Rooms I have built in the past have been similar treatment and I have been perfectly happy with them. But if there is something I can do on this build to take it up a notch, I am happy to listen.

Take a look at ITU document BS.1116-2. That lays out all the specs that a critical listening room needs to meet, acoustically. That should be what you are aiming for, if you want to "take it up a notch". Or two. Or three... As you can see from the link I gave you above, it is possible to meet and exceed those specs, but it takes a lot of effort, and most of all, careful design.

3) Are there too many parallel walls in the live room?

How many do you think there should be? Why are you worried about parallel walls? The only two big issues with parallel walls are flutter echo, and sharpened modal response. Both can be dealt with. It's a myth that you can't have parallel surfaces in a live room. It's a myth that rectangular rooms are bad. Take a look at Abbey Road, for example: Every single room in the place is rectangular, and parallel.... Parallel per sé is not necessarily bad: it's what you do with it, or don't do with it, that makes it good or bad.



- Stuart -