John Sayers' Recording Studio Design Forum Archive

Stuart,

Here's an update on what has happened in the build over the past month.

I've reinforced the control room floor with 4x4s and jacks getting rid of the bounce and have managed to separate the wall frames in the CR by splitting the 2x10 cap that was coupling the inner and outer frames together.
Now that the inner and outer frames are self supporting I have to design and construct an inner ceiling frame for the CR. That will leave the floor decking as the only point that the inner and outer walls touch, which i cant really do anything about. I plan to do the control room floor with 1" concrete board, possibly use a thin layer of self-leveling concrete to seal it all up, and finish with a ceramic or stone tile . I know its not as good as starting over from scratch, but its a step in the right direction. Also, I've hired my HVAC contractor who has done two nice studios in town and knows all the ins and outs which is a big relief. The rough-in begins tomorrow!
Before doing anything else, I want to lock in my CR design and the main thing keeping me from doing so is figuring out the soffits. I've seen many different designs and methods and dont know which one I should go with. I've studied the Sayers' soffit style and a few others. One in particular was the soffit at ClearTrack Studios designed by Wes Lachot. You can see it in a video here..http://youtu.be/oVnVpS5dM-E
He incorporated the soffit into the wall design and drywalled the front of the soffits and then went back and did what looked like a layer of OSB and MDF. Unlike in the Sayers style where I believe the drywall layers are on the inner wall studs and the soffits are constructed within the leaf from OSB and MDF. Is that correct? In the Lachot design, no ports or bass traps are used because the soffit is actually part of the leaf and can't be penetrated. It looks like just the boxes that house the speakers we're built and they seat in the frame and extend back into the insulated air cavity that is between the inner and outer wall frames. In the Sayers' design, the extra space above and below the speaker can be used for trapping. I'm sure each style has its pro's, cons, and specific to the scenario but I don't know what they are. I know the main attribute of a soffit is to be rigid and sturdy.
Personally, I like the Lachot design because the soffit frame is a part of the wall frame and having the drywall on the fronts seems like it would make it a very massive surface compared to just using OSB. But the speakers being in the air cavity between leaves makes me uneasy. It feels like there should be another layer behind them to contain any backward resonance from hitting the next leaf, but isn't that the whole point of "front-loading" the speakers anyway? So that all sound is pushed forward, instead of 360 degree resonance? Please correct me if I'm wrong.
I guess my question is should I design my soffits to be a part of the leaf or inside of the leaf?
I've also been considering not soffit mounting any monitors since I always work on nearfields. But of course, you gotta crank it once and a while!
I've had my eye on Barefoot monitors for a while now, which cant be soffit mounted due to their 360 design. Lets say I we're to use such a configuration. How would be best to handle the walls where the soffits would've been? I want to keep the 30 degree angles of the walls but should I make the surfaces absorptive, maybe broadband or targeted slots, or reflective?
Trying to keep it short although I have a million questions.
Thanks for any input and hope you are well!

Jason

Hi again Jason. Glad to see you are still moving forwards!

I plan to do the control room floor with 1" concrete board, possibly use a thin layer of self-leveling concrete to seal it all up, and finish with a ceramic or stone tile

That's probably about as good as you can hope for, given the limitations of the structure. Make that self leveling cement as thick as possible, within reason, and as thick as your structural engineer will allow!

Also, I've hired my HVAC contractor who has done two nice studios in town and knows all the ins and outs which is a big relief.

Great! hopefully he'll be able to do it right, with decent silencer box design, slow speed, and high volume.

I've seen many different designs and methods and dont know which one I should go with.

The basic concept is simple: You need a very solid, rigid heavy, massive structure that cannot be moved easily by the speaker vibrations, and you need a very solid, rigid massive baffle (front panel) that also cannot be moved by vibrations. The main difference in the methods of how to actually build it, is based around weather or not those two "very solid, rigid massive" things are tied together, or kept separate. Both approaches work.

One in particular was the soffit at ClearTrack Studios

Yeah, I've seen plenty of photos and videos of that place floating around the internet. Nice looking place, isn't it?

He incorporated the soffit into the wall design and drywalled the front of the soffits and then went back and did what looked like a layer of OSB and MDF.

Yup. And probably plenty of other stuff that you can't see!

Unlike in the Sayers style where I believe the drywall layers are on the inner wall studs and the soffits are constructed within the leaf from OSB and MDF

It's the same concept, if you look closely... There's no difference.

In the Lachot design, no ports or bass traps are used because the soffit is actually part of the leaf and can't be penetrated.

It might look that way, but I'm betting that some place in there is plenty of ventilation for those speakers! They need cooling....

What you see in John's soffit designs are NOT acoustic ports: they are ventilation ports, that allow the cooling air to flow up behind the back of the speaker, then return to the room. If you don't want to see those ventilation ports, then there's no problem hiding them inside the soffit some place, provided that you also include suitable silencer boxes if the HVAC ducting from the speakers then goes straight out of the room.

It looks like just the boxes that house the speakers we're built and they seat in the frame and extend back into the insulated air cavity that is between the inner and outer wall frames.

Once again, it's the same concept as with John's design: there is a massive box around the speaker itself that holds it rigidly in place. With both designs the speaker itself is NOT in the air gap between the leaves: that would be silly.

The only difference I can see is that with John's design the speaker box is vented with the soffit back to the room, whereas with the other design the box is vented in some other way that cannot be seen, and that does not come back into the room. If you have the budget to do the extra complexity for that ventilation, then by all means go for it! The end result won't be any different. Or use passive speakers that run very cool and do not need cooling, even when run for long periods of time at high power.

However, you did say you were planning on using BM5A's, which are active, have huge heat sinks on the rear that get hot, and can't be soffit mounted anyway! Or at least they cannot be soffit-mounted not easily, and certainly not the way seen in that video: You have rear-firing bass extension ports on those....

In the Sayers' design, the extra space above and below the speaker can be used for trapping.

John normally only uses the space below for trapping. The space around and above the speaker is filled with insulation, to damp cavity resonance. But there's an awful lot if useful real-estate under a soffited speaker, and it seems such a shame to just waste that, when it could be put to good use for trapping....

Personally, I like the Lachot design because the soffit frame is a part of the wall frame

It is with John's design too. Especially so if you build the front wall inside-out, as John normally does.

the drywall on the fronts seems like it would make it a very massive surface compared to just using OSB

Why? Drywall weighs about 650 kg/m3, give or take (depending on manufacturer, style, etc). OSB weighs about 600 kg/m3, and some types as much as 640 kg/m3. So there's not much in it. OSB is also more rigid than drywall...

But the speakers being in the air cavity between leaves makes me uneasy.

The speakers are NOT in the air cavity! Take a close look at the video again, around 1:35 to 1:48: There are several views that clearly show the box that will later contain the speakers. I'm betting those boxes are massively constructed, with rigid framing around them.

It feels like there should be another layer behind them to contain any backward resonance from hitting the next leaf,

Well, yes, I do have to agree with you there: if the box does resonate for any reason with that design, then that resonance will indeed be inside the wall cavity, which is not a good place for it.... On the other hand, with John's design, that cannot happen...

isn't that the whole point of "front-loading" the speakers anyway? So that all sound is pushed forward, instead of 360 degree resonance?

Well.... sort of! The issue is correction of power imbalance. With any free-standing speaker, the high frequencies are projected straight forwards, like rays of light, while the lows wrap around behind the cabinet and spread out in all directions, like a balloon. So the highs will be 6 dB louder than the lows, since the highs are going out into "half space" (the hemisphere in front of the speaker), while the lows are going out into the full sphere ("full space") all around. so if you pump the exact same power into all frequencies, then the lows would sound 6 dB quieter. The frequency where the change from "half space radiation" to "full space radiation" occurs is know as the Baffle Step Frequency, and is set by the width of the front panel of the speaker itself. If you then extend that front panel infinitely in all directions, then all frequencies are no forced into half-space, and there is no longer any power imbalance. That's what a soffit does: it forces all frequencies to radiate into half-space. Except, of course, with a rear-ported speaker. With rear ported or side ported speakers, things are different since a lot of the low energy is also coming out that port, and being lost inside the soffit....

I guess my question is should I design my soffits to be a part of the leaf or inside of the leaf?

In BOTH cases they are part of the leaf! Technically, the soffit removes the speaker from the room and thus also removes all the associated artifacts, since the speaker is flush with the inner-leaf of the room.

What you are talking about is different CONSTRUCTION techniques, not different acoustics. Both techniques, (and the Barefoot technique as well...) accomplish the same thing, acoustically: remove the speaker from the room, and hold it rigidly in the wall.

I've also been considering not soffit mounting any monitors since I always work on nearfields.

If you don't soffit-mount, then you re-introduce all those nasties that soffits eliminate, such as SBIR, comb filtering, other forms of phasing issues, reflections off the walls behind the speakers, modal coupling, etc., etc,. etc. ... There's a reason why studio designers flush-mount their speakers in world-class rooms, and that is to ensure that they sound as best they possibly can, the way the designer intended, with as little distortion as possible coming from interactions with the room boundaries.

I've had my eye on Barefoot monitors for a while now, which cant be soffit mounted due to their 360 design.

BM5A's suffer from the same issue: they are rear-ported.

Lets say I we're to use such a configuration. How would be best to handle the walls where the soffits would've been? I want to keep the 30 degree angles of the walls but should I make the surfaces absorptive, maybe broadband or targeted slots, or reflective?

If you don't soffit mount, then the second-best is to move the speakers far enough away from the walls that SBIR is no longer an issue, which means that they need to be at least 1.5 meters away from all walls, and preferably 2 or more meters away. I'm not sure that your room is big enough to be able to do that. The THIRD best thing, is to make the room rectangular and push the speakers right up against the front wall, where SBIR will be forced up the scale to frequencies that aren't so objectionable.

Trying to keep it short although I have a million questions.

Questions are fine! That's what this forum is all about!!!


- Stuart -

Hey Stuart!

Hope things are well, and Thank You for responding!

That's probably about as good as you can hope for, given the limitations of the structure. Make that self leveling cement as thick as possible, within reason, and as thick as your structural engineer will allow!

The jacks and spacing I used can support a metric shit-ton of weight. All in all, whatever floor finish I end up going with will be the equivalent mass of a 2" thick concrete slab.

Great! hopefully he'll be able to do it right, with decent silencer box design, slow speed, and high volume.

The HVAC has been "roughed-in" and ready to pass the initial framing inspection before we start doing the finishing aspect of it, i.e. the silencer boxes, and how the hvac will actually penetrate the inner leaf once their inner framing is completed.

It might look that way, but I'm betting that some place in there is plenty of ventilation for those speakers! They need cooling....

If I saw it correctly, later in the video it shows that those that the cavities that I described between the CR and LR were used for closets to house cabling or gear between rooms?

John's soffit designs are NOT acoustic ports: they are ventilation ports

Sorry, That's what I meant. Of course they will have to vent and breathe somewhere.

With both designs the speaker itself is NOT in the air gap between the leaves: that would be silly.

Agreed. Suspicion confirmed!

However, you did say you were planning on using BM5A's

I do not plan to soffit mount any of my near field monitors. My BM5a's and NS-10's will be on the desk area. The soffit walls would be for housing a loudspeaker around the size of an Augsurger GA 115. I guess my question was should I build the inner leaf (framing/drywall/etc) and then construct the soffits within it?

It is with John's design too. Especially so if you build the front wall inside-out, as John normally does.

I understand building a wall inside-out, but if I we're to construct the front wall inside-out to make for easier framing of the soffits, how would I construct the other walls? Can you construct the front wall inside-out and construct the other walls inside-in, or would you construct all walls of the CR inside-out?

The speakers are NOT in the air cavity! Take a close look at the video again, around 1:35 to 1:48: There are several views that clearly show the box that will later contain the speakers. I'm betting those boxes are massively constructed, with rigid framing around them.

Exactly!

In BOTH cases they are part of the leaf!

So I guess what your saying is I kinda answered my own question.

I've had my eye on Barefoot monitors for a while now, which cant be soffit mounted due to their 360 design.
BM5A's suffer from the same issue: they are rear-ported.

You must be thinking of a different Barefoot. This is the Barefoot I'm speaking of... http://www.barefootsound.com/micromain27gen2.html
When I said 360 design, I meant that there are speakers on 3 sides of the cabinet, the front for the mids and highs, the sides for the lows. Soffit mounting isn't possible.

On Another Topic:

I'm planning to do my LR iso booths with wood framing on a concrete floor. Whats the proper way to connect the inner framing of an iso booth to a concrete floor? Bolt the 2x4 plates to the concrete floor with a caulked seal? Use a membrane or "spring"(neoprene/expansion joint material) between the concrete and the 2x4 plate to decouple? ....Planning ahead...

Thanks for any advice. I'll post updated pics and .skp soon

Jason

Hi Jason

Generally (I believe) It shouldn't be necessary to decouple the wood framing from a concrete floor
…you can still place some rubber under your walls to compensate for level irregularities if necessary…

In that case:
- Get a large piece of neoprene (or a yoga mat for a low budget alternative) and cut sections the width of the base plate and place them under the base plate
- drill a hole thru the stud and then (with a masonry bit) drill into the concrete floor
- drop an anchor bolt into the hole
- put a piece of neoprene tubing into the hole and around the bolt in order to prevent vibrations from transfering from the bolt to the stud
- add a neoprene washer and then a metal washer

Here are a few pics I got around the Forum, where I found these info too…. Just echoing the experts' advice and hopefully save them some time Three caulk passes (one in the middle and two on each side of the base plate) would be a good thing to do if you can


Hope this helps

Fantastic build by the way…looking forward to see it all coming together


Simo

What Simo suggests is a good idea, but it should be done with care, using the right products for the job. You can either do all the math yourself to ensure that you get it right, or you can buy something like the IsoSill products, where they already did that for you.

The jacks and spacing I used can support .... of weight. All in all, whatever floor finish I end up going with will be the equivalent mass of a 2" thick concrete slab.

All the same, you should still get a structural engineer involved: he's the only guy who can say for sure if what you are doing is structurally sound or not.

If I saw it correctly, later in the video it shows that those that the cavities that I described between the CR and LR were used for closets to house cabling or gear between rooms?

I didn't notice that, but I also didn't look for it.

I guess my question was should I build the inner leaf (framing/drywall/etc) and then construct the soffits within it?

To my way of thinking, that's the best (not to mention easiest! way of doing it.

Can you construct the front wall inside-out and construct the other walls inside-in, or would you construct all walls of the CR inside-out?

You can do it either way. Yes, it is possible to do the side walls traditionally and the front walls inside-out. No problem. You can also do the walls traditionally and the ceiling inside-out, or vice-versa. You just need to pay more attention to how you do the framing where the two meet, but as long as that is done right, then there's no problem with "mix and match" for studio walls.

So I guess what your saying is I kinda answered my own question.

You must be thinking of a different Barefoot. ... When I said 360 design, I meant that there are speakers on 3 sides of the cabinet, the front for the mids and highs, the sides for the lows. Soffit mounting isn't possible

No, it's the same Barefoot. There's only one of Thomas as far as I know! I don't think this planet could handle more than one....

The issue is that you can only successfully soffit-mount ANY speaker if it ONLY radiates energy forwards, from the front baffle. ANY speaker that also radiates energy in other directions, either with additional drivers, or with ports, or anything else that does not radiate forwards, is not really a candidate for soffit mounting. That's the point I was trying to make.

I'm planning to do my LR iso booths with wood framing on a concrete floor. Whats the proper way to connect the inner framing of an iso booth to a concrete floor?

You can do it the way Simo suggested, and you would do that for either of two reasons: 1) if you want to try to "float" your walls acoustically, so they transmit less vibration into your floor (and the other way too: floor to wall), and 2) If your concrete floor is in a bad state, ie., it is cracked, uneven, bumpy, flaky, etc., and you want to get a really good seal between the wall and the floor. If you go the first route, then you have some math ahead of you to ensure that your wall really does float properly. But if you don't need either of these two approaches, then the best method is to just bolt the sole plate to the concrete, with a good seal. That "good seal" can be achieved with acoustic caulk: before you put the sole plate down, run a bead of caulk down the full length of that sole plate, along the center line, then another bead about an inch each side of that. Set it in place and bolt it down, then fill any any remaining gaps that you can see under it, with more caulk. The caulk under the edge or each layer of drywall, as it goes up: place thin shim under the drywall to space it off the floor while you nail it in place, then pull the shim and caulk the gap. This method gives you multiple independent seals, which is A Really Good Thing! Seals are your best friend, in acoustic isolation.



- Stuart -

Hey Stuart,

Hope your holiday season has treated you nicely!

I'm still a bit hung up on designing my soffit for the CR.

What is your basic design concept for the room? Are you going with LEDE, RFZ, CID, MR, or something entirely different? That's the starting point.

I'm going for RFZ and an attractive design that eats up as little square footage as possible.

....In the end, my speakers will have to be angled down at the mix position because they will need to be more than 4' 6" from the floor.......
-Stu says-Why? Also, not sure where you got the 4' 6" figure: Standard speaker height is 3' 11-3/4" (which is 47 1/4", or 1.2 m exactly). Why do you think that won't be high enough? You'd need a very high desk or unusually tall console to make that unworkable. What is the reason in your case? If you want your room to sound good and have mixes that translate well, you really should stick to the standards as much as possible.

I got that number (which may not be exact) from this page on John's site http://johnlsayers.com/Recmanual/Titles/Acoustics3.htm
The monitors I would soffit mount would be above the 1.2meter/4foot height(from center of cone, not bottom of cabinet). My small nearfields (i.e. dynaudios,ns10s) would be at this height, so I wanted my bigger soffit mounted loudspeakers to be over the top and clearing the nearfields and angled down to the mix position. Would you know off hand know the angle that is used in John's drawing linked above? Or better yet, how to pinpoint the proper angle. I'm sure it all has to do with distance from the mix position. I agree with what you previously said ....
[quoteNever, ever, ever, ever more than 10°, and the usual recommendation is not more than 7°. Personally I've never gone over 5°: ][/quote]
Is there an equation for this ? speaker height / distance from mix positon, etc?
If you have any previous drawings of angled soffit mounted speakers that I could study they'd be a huge help!

I'm also curious about how to handle the ceiling above the mix position.
I've seen in other designs where the ceiling slopes gradually upward from the front wall towards the mix position at around 7-12 degrees to its highest point, and then the angle either transitions to the typical 90(square) or to another gradual upward slope to the back wall of the CR.
Thoughts on this???

thanks Stuart, and Thanks to Simo for chiming in!

Jason

I got that number (which may not be exact) from this page on John's site http://johnlsayers.com/Recmanual/Titles/Acoustics3.htm

On the "Speakers" tab? The number I see there is 1.2m, which is 47-1/4" (3'11-1/4"). Or maybe I'm looking in the wrong place?

But anyway, "standard" speaker height is 1.2m. Or at least, that's the way it is defined in the ITU, EBU and AES specs (among others). That doesn't mean you HAVE to set up your speakers that way, but it's still a good idea to do so. And like John mentioned on that page, if you do have to raise your speaker above 1.2m for whatever reason, then it needs to be tilted down so that the acoustic axis is aimed at your ears again. That said, tilting a speaker introduces a whole new bunch of problems, such as reflections of the console/desk, and impaired psycho-acoustic perception of sound, so it has to be done with care and understanding. That's why I mentioned the "never more than 10°, some say 7°, I've never gone beyond 5°" comment.

The monitors I would soffit mount would be above the 1.2meter/4foot height(from center of cone, not bottom of cabinet)

Depending on the make and model of your speakers, it might of might not be the cone of the tweeter. This is all about the acoustic axis of the speaker, which is the point on the front face where the combined sound of the woofer and tweeter appears to come from, and is generally at some point on the imaginary line that joins the center of the tweeter to the center of the woofer. It is generally much closer to the tweeter than the woofer, and therefore some people say to just use the tweeter as a rough guess, but for precision it is better to found out exactly where it is. Some manufacturers (such as Genelec, K&H, and others) publish that information for all of their speakers. Others will give it to you if you ask. Others don't know/don't care, so you probably shouldn't be buying their speakers anyway!

Would you know off hand know the angle that is used in John's drawing linked above? Or better yet, how to pinpoint the proper angle. I'm sure it all has to do with distance from the mix position.

Not sure what angle John used for that drawing, and I'm betting he did not show it on purpose, since all rooms are different. If he where to put an angle on there, then you'd see dozens of rooms built with that exact angle even when it was not appropriate!

Fortunately, it's easy to figure out. The key is the position of your ears in the room: They should be at 38% of the room length from the front wall (theoretically "perfect" position, but NOT written in stone) and 1.2 m above the floor (which is the average ear height of most people when seated). So if your room is 10m long, then your chair should be set up so that your ears are 3.8 m from the front wall and 1.2m above the floor. Then set up your speakers such that they are about 28% of the room width away from the side walls, and angled inwards at about 30°. Now move them around so that the imaginary axes extending from the two speakers, intersect at a point about 30cm behind your head. Set up like that, those imaginary acoustic axes will be grazing just past the edge of your ears. The tilt angle of the speakers should be just enough so that the axes are lined up with the center of your ears at the point where they go past (in other words, the axis must get down to a height of 1.2 m at 38% of the room length).

OK, BIG caveat! All of the above is theoretical perfection, but actual reality does NOT necessarily match! Those percentages, distances and angles are just goods starting points, not rigidly fixed positions in space. You won't be arrested by the Room Geometry Police if your speakers are actually angled 27° or 33°, or if you ears are at 41% or 36% of room length, or if your speakers are 26% or 30% of room width! You are allowed to change all of those a bit to suit the conditions of your room, without any problem.... provided that you understand the implications and the trade-offs.

But that does give you the basis for figuring this all out, and getting things angled and positioned correctly.

Is there an equation for this ? speaker height / distance from mix positon, etc?

The easiest way by far is to do this in SketchUp, then angle the things as needed to see how they end up. That's the way I do it.

If you have any previous drawings of angled soffit mounted speakers that I could study they'd be a huge help!

I do have some I could show you off-line, in private, but I can't put them out on the forum in public since they come from studio designs I did for paying customers. Hope you understand! PM me.

I'm also curious about how to handle the ceiling above the mix position.
I've seen in other designs where the ceiling slopes gradually upward from the front wall towards the mix position at around 7-12 degrees to its highest point, and then the angle either transitions to the typical 90(square) or to another gradual upward slope to the back wall of the CR.
Thoughts on this???

Very positive! Those are my thoughts. For an RFZ design, that's a given: you have to slope the front section of the ceiling somehow, to force those first reflections way behind your head. However, once again the exact angle depends on each individual room, and the only real way to determine that is by "ray-tracing" inside a 3D model, using SketchUp or something similar. Generally you'll need more than 12°, though. 12° is for flutter echo, not for RFZ.

- Stuart -

Stuart,

Your advice on my hang-ups with my CR design is helping me move along. I'll post a sketchup soon. Honestly, I got so burned out on designing the CR that I had to start working on another area of the studio...

BOOTH 1

....yer gonna hate this..

The first iso booth I want to work up is the drum booth at the rear of the live room.
To refresh, i'll try to attach a jpg of the full floor layout here. If I fail, its on page 1. The Existing dimensions of the area to be used is +/-11'H x 11'W x 11'D The existing roof trusses are 10' above the existing paver floor at the rear of the building and slope upward and inward to 14'. "shed" style.
If you were stuck with these dimensions, How would you best utilize the space within to make it into an iso booth? With its cubic dimensions and
not a lot of square feet to work with I'm on the fence on how to handle it. Obviously the dimensions are bad. But it can still be made into an acoustically pleasing isolated space though, right ? RIGHT!!
I've come up with 2 ideas so far of what I think would work. Knowing that cubic dimensions are bad I tried to angle the walls and ceiling to get it as much out of square as possible, but I'm not sure if I did a good job. Feel free to shoot me down!
With both designs I have the same question about using angles in rooms to help acoustics. When constructing the inner leaf of an iso booth with these dimensions, to throw the room out of square I'd assume you'd angle some walls. Would it be better to frame the inner leaf as a square and use angled slot walls to get the angles and absorbtion out of the open space of the room, or frame the inner leaf itself according to the angles?
Here are my 2 designs... For much easier navigation, and saving about a million words in this text, you can download the SketchUp drawing from this link...
http://www.sendspace.com/file/qxttfm
On the sketchup, You will find 2 full inner and outer drum booth frames. The one on the left is DB 1, the one on the right is DB 2. The drawings layers match up on 1 & 2. All of the "Outer" named layers are real life existing. All of the "Inner" walls, ceiling, drywall, insulation, slots, etc, don't exist.
Have a look around the drawing and let me know if you think I'm heading in the right direction or if I'm way off. Any suggestions as to what to do differently would be awesome. or if you'd like to alter the drawing and send it back that'd be cool to! I'm open to any and all questions.
.....ready the firing squad....

Thx

Jason

A quick question I forgot to ask when we were discussing CR ceilings..
My previous question-

I'm also curious about how to handle the ceiling above the mix position.
I've seen in other designs where the ceiling slopes gradually upward from the front wall towards the mix position at around 7-12 degrees to its highest point, and then the angle either transitions to the typical 90(square) or to another gradual upward slope to the back wall of the CR.
Thoughts on this???

You're response-

Very positive! Those are my thoughts. For an RFZ design, that's a given: you have to slope the front section of the ceiling somehow, to force those first reflections way behind your head. However, once again the exact angle depends on each individual room, and the only real way to determine that is by "ray-tracing" inside a 3D model, using SketchUp or something similar. Generally you'll need more than 12°, though. 12° is for flutter echo, not for RFZ.

What about using a cloud over the mix position and front 38% of the room?
As opposed to building an angled ceiling, what about keeping the ceiling flat and floating a cloud? my CR is x14'Wx20'Lx10'H. If I angle the ceiling I've got about 2 feet of height to play with within the 7.6' that is 38% of room length. I was planning to have a cloud from the beginning. I just want to know if having a cloud replaces the need for an angled ceiling since the cloud will be absorbing or at least deadening reflections from above. Or is there a middle ground?

Thanks

Jason

Back on the topic of Booth 1,

The exterior walls that surround the area for the booth are made of 2x6 studs. The outer side of the wall that is exposed to the outside world consists of a layer of 1/2" plywood with hardy plank siding on top. The inside is unfinished, just insulation in the cavities between studs. Would it help to put a layer of drywall up on the inside of the exterior walls to add mass and a better seal the inside of the building off from the outside world before framing the inner wall of the booth?, Or would doing so make it a 3-leaf wall and have negative effects?
From the outside world to the inside of the booth the existing layers and the ones I construct would go in this order....
Outside world-plank siding-1/2'ply-2x6 studs/insulated cavity- 1 layer 5/8"drywall- 2" air gap between framings-2x4 stud/insulation-hat channel on clips-2 layers 5/8" drywall(minimum)- Inner Booth

Sorry I didn't roll my last posts all into one

Jason

What about using a cloud over the mix position and front 38% of the room?

It needs to be on your first reflection point, which is somewhere in that range. Normally hanging it over the desk/console is about right, but making it big to cover a larger area is very good.

I was planning to have a cloud from the beginning. I just want to know if having a cloud replaces the need for an angled ceiling since the cloud will be absorbing or at least deadening reflections from above. Or is there a middle ground?

You can do a "hard backed cloud", which sort of has the same general effect as an angled ceiling. The concept is simple: put a thick, hard, solid, rigid piece of wood on top of the frame that holds the cloud in place, then tilt the whole cloud: lower over the speakers, higher over your head.

Would it help to put a layer of drywall up on the inside of the exterior walls to add mass and a better seal the inside of the building off from the outside world before framing the inner wall of the booth?,

Yes! Definitely! That's called "beefing up" and is indeed a very good idea for increasing isolation.

Outside world-plank siding-1/2'ply-2x6 studs/insulated cavity- 1 layer 5/8"drywall- 2" air gap between framings-2x4 stud/insulation-hat channel on clips-2 layers 5/8" drywall(minimum)- Inner Booth

Welll, no, not like that. That would, as you say, be a 3-leaf situation. The way to do it is to beef up BETWEEN the studs on that wall, from inside the building. In other words, it would be: "Outside world-plank siding-1/2'ply - 1 layer 5/8"drywall - 2x6 studs/insulated cavity- 1" air gap between framings - 2x4 stud/insulation - 2 layers 5/8" drywall(minimum)- Inner Booth". Also note that I reduced the gap between framing to 1", and dropped the clips and channel... if the inner-leaf wall is already decoupled, then you don't need to decouple it again. You'd only need the clips and channel if the inner-leaf framing was not fully decoupled. Trying to recall if that's the case with your build, but I don't remember off hand... And I'm too lazy to go back over the thread right now, as it is 02:30 AM! I gotta get some sleep---...

- Stuart -