New control room design. Ceiling workable?

#1

Originally posted on John Sayers Forum. Original topic focus was on which room to use. I've since decided on the big room. Advantages: favourable dimensions and volume, better monitor distance, and a 'live' rear half for occasional recording.

But one big unknown remains. Ceiling slope is across the room: right (2.5m) to left (2.8m). So the first question is can it work? Given that it's only 6mm ply, can extensive treatment with >12mm ply hangers, or a huge cloud negate its influence?

Second: can the sloping back wall work? My understanding so far is yes. Assuming it's treated with slat resonators, I'm hoping it may even be better than a parallel wall for a 'live' sound.

Purpose
Electronic music production i.e. control room.
Plus occasional recording in back half of room.

Goals
Aiming for excellence! Music for large outdoor PAs. Quality bass responsiveness and detailed mids and highs are essential.

Room
4.2m x 6.8m.
Timber frame.
Ply floor 400mm off the ground (makes HVAC and wiring easy to install). To be covered with laminated floorboards.
Raked ply ceiling with exposed rafters. 4deg slope. 2.5m high at front wall, rising to 2.9m at the back. Insulated. Corrugated roof.
Gyprock walls and weather boards on three sides. Minimal insulation.
Sound containment not a consideration. No close neighbours.
Need to minimise cicada and rain noise.

Proposed treatment
RFZ.

Soffits: monitors are KRK VXT8 (200mm woofer). Similar to Barefoot’s method; monitors on separate decoupled stands. Concrete bezel. MDF surrounding.

Ceiling: a full layer of insulation to reduce rain noise (the existing insulation in the cavity between the ply and the tin roof isn't satisfactory). Plus extensive coverage with hangers or a substantial cloud. Exposed rafters will make install easy.

Rear wall: hangers as large as necessary. Superchunks in rear tri-corners if beneficial.

Side walls: hangers and slat resonators.

Windows partly covered or replaced with narrower ones.

Glass sliding door will be defunct.

Budget
Ideally $2k for materials. But flexible if justifiable. I have 50sqm of 50mm Acoustisorb 3, and a fair bit of timber in the current studio. Doing the work myself. Plenty of carpentry experience between myself and friends.

Room modes attached. Not sure how useful given the change in ceiling height. Used 2.7m in the calculations. Looks favourable.

#2

Hi there WhoRay, and Welcome to the forum!

Great first post, by the way!

A few comments on that:

I've since decided on the big room. Advantages: favourable dimensions and volume,

Good choice! At 28 m2, it's certainly a good size.

But one big unknown remains. Ceiling slope is across the room: right (2.5m) to left (2.8m). So the first question is can it work?

Yes it can. Depending on how accurate you want your room to be, you might be able to leave it as it is, or you cloud create a "false" ceiling across half of it, that mirrors the other half. The difference in height isn't too bad, so you might be able to get away with it, using just treatment (eg, a large hard-backed cloud, plus targeted absorption above). Or you could build the fake section, to get better symmetry.

Second: can the sloping back wall work? My understanding so far is yes.

Right. It's not really an issue if the rear of the room is not 100% symmetric. Ideally, it would be nice to do that, but it's not absolutely essential.

Assuming it's treated with slat resonators, I'm hoping it may even be better than a parallel wall for a 'live' sound.

... and there's the big problem with a single room that needs to serve as both live room and also control room! A live room has one set of acoustic needs, while a control room has a very, very different set of acoustic requirements. And I'm using "needs" for one and "requirements" for the other on purpose: A control MUST meet a certain well-defined set of acoustic parameters: that's a requirement, if you want to use the room for serious mixing and not go crazy trying to get your mixes to translate. On the other hand, musicians NEED a certain the acoustic response in the room in order to play well, and in order to record well. The two acoustic situations are totally opposite. For example, a control CANNOT have reflective surfaces that could cause strong non-diffuse reflections arriving at the mix position within the "Hass Time". In technical terms: No reflections above -20 dB in the first 20 milliseconds. Often referred to as the "20/20" criteria. Hence my nick-name: "Soundman2020". The "2020" part has nothing to do with the year 2020, but rather with the acoustic requirement for a usable mixing room.

All that preamble, to get to the point: If you want a usable mix room, then building your rear wall as a slat wall is a bad idea... unless it is done VERY carefully! In most high-end control rooms, the entire rear wall is one huge, deep bass trap: wall to wall, and floor to ceiling. If the room is large enough, then the rear wall might also have some type of diffusion on it, but that covers the bass trapping behind it. The room needs to be fairly large for that to happen, since you need at least 3m between the diffusor and the mix position. for acoustic reasons. But regardless of room size, the rear wall is the largest problem in an control room. It needs tons of attention, acoustically.

The problem is, the rear wall of a well-treated CR, ends up being rather unpleasant for musicians to play, and for tracking. And if you make it good for the musicians, then it is bad for mixing.

In other words, when you have a single room, you have a direct conflict. The best solution is this:
What is variable acoustics? How do I do that?

Electronic music production i.e. control room.
Plus occasional recording in back half of room.

That clarifies your decision in how to treat!

Design it as a control room, then add in some variable devices that will make it better for playing/tracking.

Goals
Aiming for excellence! Music for large outdoor PAs. Quality bass responsiveness and detailed mids and highs are essential.

That also clarifies even more the basic treatment design. The rear end of your CR has to be bass trapping, designed for a good control room acoustic response.

Ply floor 400mm off the ground (makes HVAC and wiring easy to install). To be covered with laminated floorboards.

Careful with that! Cavities under the floor can be resonant, and can play havoc with the room response.

Sound containment not a consideration. No close neighbours.
Need to minimise cicada and rain noise.

It's pretty much the same: blocking sound from getting out, is the same as blocking sound from coming in. The best way to go about this, is to identify how much isolation you need, in terms of decibels, considering both out-going and in-coming sound. Based on that, you can decide on how much isolation you need, and implement that.. BEFORE you think about treatment. Those are two entirely different concepts in acoustics, but often get confuses and mixed together. They are actually opposites! The things you to do isolate a room, will make the acoustic response inside WORSE, not better. Isolating a room implies dealing with all six complete surfaces: All four walls, and the floor, and the ceiling, 100% coverage on each. ALL of those must be included, in order to isolate the room. Treatment, on the other hand, can go just where it is needed, not necessarily covering all the surfaces.

Proposed treatment
RFZ.

Smart move!

Soffits: monitors are KRK VXT8 (200mm woofer). Similar to Barefoot’s method; monitors on separate decoupled stands. Concrete bezel. MDF surrounding.

That's one way of doing it, yes. There are others. But the objective is the same in all cases: get the front panel of the speaker itself flush with the "wall" surface that it is mounted in, make that surface massive and very rigid, and mount the speaker in some way that it cannot transmit its own vibrations into the structure.

Ceiling: a full layer of insulation to reduce rain noise

Unfortunately, that won't do much. A layer of insulation on the ceiling is treatment, not isolation. Isolation requires mass, and hermetic seals. Insulation s not massive, and is porous (not sealed). As I mentioned above, isolation and treatment are two different things, involving different concepts and different materials.

(the existing insulation in the cavity between the ply and the tin roof isn't satisfactory).

That's part of the issue: That arrangement of tin roof/insulation/thin ply is not going to isolate at all well. Adding more insulation under the ply, won't make much difference at all, unfortunately.

Rear wall: hangers as large as necessary. Superchunks in rear tri-corners if beneficial.

Right! Superchunks in the corners are definitely beneficial! And so are hangers. In fact, you can combine those, or just use hangers all the way across, deeper in the corners, a bit less deep in the middle.

Side walls: hangers and slat resonators.

mmmmmm.... maybe! But you don't really have enough space to do that. In order to be effective, the old Tom Hidley concept (later imitated by Philip Newell and others) needs a depth of at least 50cm on each wall, to implement properly, and Tom soemtimes used a meter or more.... So you need a large room to do that! There are other, better methods for smaller rooms, like yours.

Windows partly covered or replaced with narrower ones.

Any particular reason for that? I imagine you are concerned that the speaker "soffits" will partially cover the window? If so, I would suggest that you first design the soffit modules completely, to see how big they will be, then decide if you want to shrink the window, or not.

Room modes attached. Not sure how useful given the change in ceiling height. Used 2.7m in the calculations. Looks favourable.

It's not so easy when one of the surfaces is angled, as in your case. One option is to do three different scenarios: one using the highest point, one using the lowest point, and one using the average between those two. If all three look good, then you are probably fine.

Budget
Ideally $2k for materials. But flexible if justifiable.

That's probably a bit on the low side. Studios ALWAYS cost way more than you ever expected, even for fairly simple ones... I think you'll need to dig in deeply to that "flexible" part!

- Stuart -

#3

WhoRay wrote:Source of the postBudget
Ideally $2k for materials.

I know that Stuart has already mentioned this but I thought I would try to give you a comparison. As you are in Australia I am assuming that we are talking Australian dollars.You have 28m2, I have 29.8m2 so not so different. Our buildings are different and so the required materials will be different and we are in different countries but I agree with Stuart that your budget will likely need a lot of flexibility.

For example, I spent all of your budget buying the plasterboard for my studio (that does not include screws, tape, etc.). I spent half of your budget on caulk. I spent almost twice your budget on wood (at pre-Covid prices) yet I still have a fair bit more to buy (at much higher Covid prices). I spent all of your budget on tools, many of which I did not think I would need. The Regupol underlay (only the underlay plus delivery) for my studio's wooden floor cost your entire budget. I could go on but I hope you see that costs that you perhaps have not planned for, and in some cases cannot forsee, will crop up.

#4

Yup, here's a good formula: multiply what you think the total cost will be by a factor of 10 and that will get you in the ballpark of reality. :mrgreen:

#5

a decent estimate for a fully isolated and acoustically treated studio - without equipment - take the high-end home per square-unit-cost (e.g. $250/ft2, £1000/m2, etc) in your area (this cost should include the materials and labor for fine finish) and use that. so, if my population area for a high-end home is about $300/ft, and my design is 500ft2, it would be reasonable to expect my build out to be $150K. this presumes that you're paying someone to do all the work - design, construction, finishing, wiring, hvac, lighting, plumbing, etc etc + their contracting fees into the per-square-unit cost. so, let's decompose this to approximate what it could cost if, a) i did all the work, b) purchased all the materials.
-15% fees
-50% labor
+10% materials
6 months vs 3 months.
realistically i could expect to spend $65K to do the work myself. $55K if i get a discount on materials. and assuming i'm working every day and have moderate skills, 6 months would be a reasonable time frame. then factor in some things which require a licensed professional sign-off like electrical, plumbing, hvac. so another $2K for their time and stamps.

#6

Hi guys. Logged in to say I’m still here. Decided to renovate another part of the house first, which will simplify logistics of studio build. Been tearing the house apart since Christmas

And I didn’t see the recent replies till now sorry. Thanks! I’ll check my notification settings to see why. And I’ll reply soon.

#7

Good to see you are still around, Ray!

And I didn’t see the recent replies till now sorry.

The forum does send out notifications, but some ISP's block them, since they think it is spam. Check your spam folder: you might find the notifications in there. If so, set a filter in your e-mail client so it does NOT send stuff from the forum to spam! Some ISPs are even more drastic, and just delete the message before you even get it at all. In that case, there's not much you can do, except check in regularly to see if you have messages... Or switch to a better e-mail service! Hotmail and yahoo are two of the really bad ones. Gmail seems to be OK.

- Stuart -

#8

Okay I'm back... and ready (finally).

Thanks for detailed replies Stuart. I'll come back to each one as the plan develops I think.

Soundman2020 wrote:Source of the post The forum does send out notifications, but some ISP's block them, since they think it is spam. Check your spam folder: you might find the notifications in there. If so, set a filter in your e-mail client so it does NOT send stuff from the forum to spam! Some ISPs are even more drastic, and just delete the message before you even get it at all. In that case, there's not much you can do, except check in regularly to see if you have messages... Or switch to a better e-mail service! Hotmail and yahoo are two of the really bad ones. Gmail seems to be OK.

Using Apple's iCloud. Nothing in Spam. Have a feeling I'll be checking it regularly from now :lol:

Starlight wrote:Source of the post For example, I spent all of your budget buying the plasterboard for my studio (that does not include screws, tape, etc.). I spent half of your budget on caulk. I spent almost twice your budget on wood (at pre-Covid prices) yet I still have a fair bit more to buy (at much higher Covid prices). I spent all of your budget on tools, many of which I did not think I would need. The Regupol underlay (only the underlay plus delivery) for my studio's wooden floor cost your entire budget. I could go on but I hope you see that costs that you perhaps have not planned for, and in some cases cannot forsee, will crop up.

gullfo wrote:Source of the post realistically i could expect to spend $65K to do the work myself. $55K if i get a discount on materials. and assuming i'm working every day and have moderate skills, 6 months would be a reasonable time frame. then factor in some things which require a licensed professional sign-off like electrical, plumbing, hvac. so another $2K for their time and stamps.

The house was a renovators dream when I bought it. I've fixed a lot of problems but it still has many. I'll probably demolish it in 10-20 years. So likely this isn't the last studio I'll build, and I don't want to sink too much time and money into it.

I know the budget is unrealistic. I kept revising it down (wishful thinking). I think in the back of my mind I'd given up on improving isolation from outside noise. I'll just find other tasks to do when cicadas are loud or it's raining heavily. Benefit is if the sound isn't being isolated/contained, less treatment is needed. I know it's going to be more money but confident it's nowhere near those costs. Very rough guess $4k. I appreciate the cautionary advice though.

No professionals involved. I have all tools, flooring, framing timber, electrical wiring, and some steel framing (for attaching aesthetic fabric panels to). I have all the denser type insulation I think I'll need (e.g. for stuffing soffits). Significant costs will be ply* and insulation for hangers and resonators, fabric for panels, and MDF for soffits. Started a list yesterday. Once the layout is clearer, I'll do a costing.

* which so far I understand is fine, instead of something like homosote.

Pics attached.
- LP is blue dot.
- Soffit edges at floor level is in yellow.
- Proposed gyprock wall is in red. **
- The Acoustisorb insulation is about a 1/4 of what I have.
- That timber is for another job.

** The intention of the wall is to increase symmetry (i.e. remove that side section). Having second thoughts though: struggling to get the monitors wide enough in the reduced room size. This is the first hurdle. Will make a separate post about it.

#9

So in my original post I proposed building a wall to make the front half of the room symmetrical. But this might make the room too narrow (the Narrow Room). I'm considering not building the wall i.e. leaving the room at its full original size (the Wide Room).

Narrow Room ray trace shows that if resonators are adjacent to soffits, it seems the monitors must be no more than 2.2m apart. And even then I'm not sure that leaves a large enough RFZ. Reflections are only 150mm away from the LP. Is this acceptable? Am I cutting it a bit close? I don’t want to be constantly distracted about whether I’m sitting just a bit too far back.

My current setup is 2.3m. I was looking forward to increasing it. Pretty reluctant to decrease it.

If I don't build the wall I get a nice wide room. But the corner is an issue. I want maximum monitor distance but not at the expense of sound quality. Can the corner be remedied to meet stringent RFZ requirements or is it just not gonna work?

The modes appear to be much less ideal in the Wide Room too. For comparison, the modes of the Narrow Room are in my first post. I don't know how much weight I should give this difference.

NARROW ROOM (has wall)
Pros
- Less complex acoustics
- Better room modes
- Bonus walk-in wardrobe created
Cons
- short listening distance
- small RFZ
- smaller volume
- space feels more cramped

WIDE ROOM (no wall)
Pros
- long listening distance
- huge RFZ
- bigger volume
- feels roomier
Cons
- Corner causes unwanted reflections
- Poorer room modes
- No wardrobe

A third option may be to build the wall as planned, widen the monitors, and use hangers instead of resonators next to the soffits. But from your earlier reply Stuart, it seems I may not be able to make the hangers wide enough for them to be effective. There are limited spots for diffusion too, and I understand it's a crucial part of the balance (to avoid over-deadening). Seems like next to the soffits is ideal.

Are there other options I'm not seeing?

#10

narrow choice may be better in terms of eliminating that corner behind your left ear...

#11

Soundman2020 wrote:Source of the postIf you want a usable mix room, then building your rear wall as a slat wall is a bad idea... unless it is done VERY carefully!... That clarifies your decision in how to treat! Design it as a control room, then add in some variable devices that will make it better for playing/tracking.

Sorry, I called it a rear wall, but it's the sloping side wall at the rear. It seems like a slat wall is suitable for it.

I'm familiar with the variable acoustics concept; have read through this forum and John's forum quite extensively. I'd envisaged large hangers on the rear wall. To cover these when recording, a couple of movable panels on castors seems easiest. These could stand beside the right hand wall when mixing. Not very elegant, but I can't see how to design hinged panels in front of the hangers that won't interfere somewhat with the sound.

I'd pictured suspending angled panels on the ceiling above the rear half of the room, that redirect the instrument's sound to the side walls. Will draw up what I mean if it's not clear.

Soundman2020 wrote:Source of the post Careful with that! Cavities under the floor can be resonant, and can play havoc with the room response.

Sorry again, I needed to be clearer. The existing ply floor is 400mm off the ground (on joists). I'm putting an underlay down, and laying flooring directly on top. No cavity. Wiring will run outside, under the house, in PVC conduit.

Soundman2020 wrote:Source of the post Right! Superchunks in the corners are definitely beneficial! And so are hangers. In fact, you can combine those, or just use hangers all the way across, deeper in the corners, a bit less deep in the middle.

Think I'll just use hangers if superchunks don't have significant sound advantage. Simpler and less material.

Width: Standard ply width is 1.2m. It's easier to leave the ply this wide, but is 1.2m overkill?

Length: I know it's important to 'occupy' the corner spaces, but standard ply length is 2.4m. I need up to 2.9m to reach floor and ceiling corners. Thinking about extending length by overlapping (screwing) a short piece onto the bottom of each 2.4m sheet. Good idea?

Soundman2020 wrote:Source of the post RE: SIDE WALL HANGERS & SLAT RESONATORS mmmmmm.... maybe! But you don't really have enough space to do that. In order to be effective, the old Tom Hidley concept (later imitated by Philip Newell and others) needs a depth of at least 50cm on each wall, to implement properly, and Tom soemtimes used a meter or more.... So you need a large room to do that! There are other, better methods for smaller rooms, like yours.

Do you mean there isn't enough space for the hangers, or for slats either? If, not sure what else there is?

I'd roughly pictured: hangers on entire front half ceiling and entire rear wall. Slats on rear half of ceiling and side walls. And minimal hangers on side walls.

Soundman2020 wrote:Source of the post That's one way of doing it, yes. There are others. But the objective is the same in all cases: get the front panel of the speaker itself flush with the "wall" surface that it is mounted in, make that surface massive and very rigid, and mount the speaker in some way that it cannot transmit its own vibrations into the structure.

Max thickness readily available for MDF is 32mm. Is this sufficient? I can double if necessary, but don't want to do if there's no benefit.

Soundman2020 wrote:Source of the post That's part of the issue: That arrangement of tin roof/insulation/thin ply is not going to isolate at all well. Adding more insulation under the ply, won't make much difference at all, unfortunately.

Wasn't expecting isolation. Hoping to just take the edge off. But as I mentioned above, think I'll live with it. Don't want over invest in building a separate ceiling if it's going to eventually be demolished.

Soundman2020 wrote:Source of the post Any particular reason for that? I imagine you are concerned that the speaker "soffits" will partially cover the window? If so, I would suggest that you first design the soffit modules completely, to see how big they will be, then decide if you want to shrink the window, or not.

Yep I was acknowledging that I'll lose some of the window. I'll just box the soffit in at the rear and leave the window as is.

Soundman2020 wrote:Source of the post It's not so easy when one of the surfaces is angled, as in your case. One option is to do three different scenarios: one using the highest point, one using the lowest point, and one using the average between those two. If all three look good, then you are probably fine.

Done. No significant difference between them.

gullfo wrote:Source of the post narrow choice may be better in terms of eliminating that corner behind your left ear...

I was wondering if superchunking that forward facing wall might be adequate. But do you think it's beyond anything treatment can accomplish? Until I resolve this I'm at a stand-still.

#12

This is my last post. I consider the topic closed. Delete it if you wish.

Soundman2020 - Studio Design Forum