New control room. Monitor distance. Small vs big room

[ninox]

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EDIT 6 DEC 2021

The process of writing up my original post led me to realise I won't be satisfied with monitor distance in the small room at ~38%. I can't make the ~60% idea work; monitors end up too close to wall. And I think a ~25deg angle won't be wide enough anyway.

So my question is can I make the big room work?

From what I've read since, the angled wall in the back half may be okay. And a bigger room with better dimensions may not require significantly more treatment. Please correct me if I'm wrong.

I assume constructing the wall to create symmetry at the LP is essential.

The 4deg ceiling slope across the room is the unknown. But, given the ceiling ply is 6mm, surely extensive treatment with >12mm ply hangers could negate this?

I do want to make the back half of the room 'live' for recording. Is it possible to get a quality sound given the low ceiling height?

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Hi! Joined a few years ago. Was considering building a studio then, but plans changed. Now is finally the time. Just started research and design. Happy to donate and maybe interested in advice beyond the forum.


Purpose
Electronic music production i.e. control room.
Accomodating occassional instrument recording in back half of room but undecided.


Goals
Aiming for excellence. Music for large outdoor PAs. Quality bass responsiveness essential. Mids and highs are highly detailed.
Better sound and more comfort than current setup which is: loft space, hot, bright, dusty, noisy (cicadas and rain), not an RFZ.


Room
3.5m x 5.5m.
Timber frame.
Raised ply floor (~300mm). Will 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 board on three sides. No insulation.
Right wall is proposed (double leaf with gyprock). Building this wall will divide the currently large room into two: creating the studio space and an adjoining bedroom.
Sound containment not a consideration. No close neighbours.
Need to minimise cicada and rain noise.


Proposed treatment
Educated guesses at this stage. Still a lot to learn.
RFZ.
Soffits using timber framing. Seem essential, especially given smallish room size.
Monitors are KRK VXT8 (200mm woofer). Assuming for now they’re appropriate for soffits. Currently exploring suitability, and how to. Likely do similar to Barefoot’s method. Considering concrete bezel.
Ceiling: layer of insulation (mostly for rain noise), plus full coverage with hangers. Exposed rafters means easy to install.
Rear wall: hangers as large as necessary. Superchunks in rear tri-corners if beneficial.
Side walls: hangers and slat resonators.
HVAC will be straightforward.
Coverings: considering lightweight timbers frames with plastic layer and cloth layer, fixed to steel studs.
Windows partly covered or replaced with narrower ones.
Glass sliding door will be defunct.
Proposed door location is flexible.


Budget
Ideally $2-3k for materials. But flexible if justifiable. Have a large amount of insulation in current studio, and some timber. Currently estimating how far it’ll go. Doing the work myself. Have some carpentry experience and friends helping who have a lot more.


QUESTIONS

Summary
Big or small!? Not satisfied with viable monitor distance in the proposed small room. Wondering if better to keep big room, instead of dividing it, or if the small room is workable.


Insulation
If extensive hangers are used, is it still necessary to apply insulation to all wall surfaces? I’m assuming yes.


Size
Not sure how useful the mode calculation based on average ceiling height is. Also wondering if soffits cause significant change.

Please advise if you think the room is just too small to achieve quality bass.

Have considered using large room, but the other half isn’t symmetrical. It’d mean changing the orientation, causing a few issues:
1. The ceiling would slope across. Not very steep so perhaps hangers would negate this?
2. Part of the back wall is angled. I understand it's not too big a problem but have no idea how to remedy.
3. A much crappier view.
4. I lose a bedroom.
5. A lot more money for treatment.

Need to estimate just how treatment would be required. And I’d want to be confident about the difference in results.


Rear wall
I understand full absorption is best for this size room. Please correct me if wrong.


Side wall
Pretty much all rooms I’ve seen use resonators adjacent to baffles. I’m having trouble maintaining desirable monitor distance and avoiding reflections with this design. The ray trace shows ~1.9m as absolute max. But a minute change to resonator length/angle will cause reflections at LP. Moving my head slightly would be problematic. And the sweet spot is too small for two people. Also, there’s no depth at one end of the resonator. Not sure if viable.

1.75m is better but there still isn’t much room for error in construction. Not sure I’ll be satisfied with the result either. Current studio is 2m. Not too keen to decrease it.

Alternative: place hangers here instead, and resonators further back. Viable?

Another alternative: Extend baffles closer to side wall. Monitors spread further and angled ~25deg. LP at ~60% room length, ~3m from monitors. Never seen this done though. Viable (with enough rear wall treatment) or impossible? Very interested if this is possible.


Forum question
Rules are 750px max for pics. Guessing that’s outdated now? Can they be wider?


Any of your time is greatly appreciated.

[Soundman2020]

So my question is can I make the big room work?

Definitely! In fact, at 3.5m x 5.5m, your room is almost big enough to meet the commonly used "minimum size" criteria, of 20m2 floor area. Less than that gets harder to treat. In general "bigger is better", so don't go smaller than you absolutely have to.

I won't be satisfied with monitor distance in the small room at ~38%

Why not? Also, 38% is not a rule: just a guideline. Anywhere between about 30% and 45% can be viable, depending on the room, the speakers, and the treatment.

monitors end up too close to wall.

That's where they are supposed to be! Your room is not large enough to be able to place the monitors far enough from the front wall to avoid serious SBIR issues, so the only other option is to place them right up against the front wall (if they are free-standing), or best of all, flush mount them (a.k.a. "soffit mount"). In which case you can adjust the depth of the soffit to better accommodate your room layout, including mix position.

the angled wall in the back half may be okay.

It's fine. Not ideal, but not a serious issue either, with proper treatment.

And a bigger room with better dimensions may not require significantly more treatment. Please correct me if I'm wrong.

You are right! Smaller rooms need more treatment: bigger rooms need less (relatively speaking). That's a generalization of course, but usually a smaller room will need a lot more treatment than a larger one, and especially so if the floor area is considerably less than that "minimum recommended" 20m2 figure.

I assume constructing the wall to create symmetry at the LP is essential.

The entire front end of the room, fro the front wall all the way back to where your ears are, should be as symmetrical as you can get it: you want your right ear and left ear hearing roughly the same acoustic "signature".

Raked ply ceiling with exposed rafters. 4deg slope. 2.5m high at front wall, rising to 2.9m at the back.

That's actually pretty decent, for a CR ceiling. Another general rule: ceiling lower at the front (over the speakers) and higher towards the rear. In general, the rear end of the room can "expand" to be wider/higher, but it's not a good idea to have it getting smaller towards the back. so you are in a good situation here.

Monitors are KRK VXT8 (200mm woofer). Assuming for now they’re appropriate for soffits.

They are fine for soffit mounting. Contrary to popular belief, most speakers can be soffit mounted, with few exceptions. Even rear-ported speakers. The only oes that are "out of the question", are speakers that have drivers on the sides, top or bottom, or are designed to work as dipoles. Pretty much everything else is fair game for soffit mounting, with the right precautions.

Not satisfied with viable monitor distance in the proposed small room.

What do you consider to be "viable monitor distance"? KRK has their own specs for that, for your speakers, but with good soffit mounting you can certainly go closer or more distant, if the room design allows for that. The trick is to get far enough away that your ears are not in the "transition zone" (as some call it), and not so far away as to be beyond the critical distance (which is really hard to do, in a small room with contemporary speakers!). With 19.5m2, you have many options open to you.

If extensive hangers are used, is it still necessary to apply insulation to all wall surfaces? I’m assuming yes.

Probably not. If you do that, you run the risk of "sucking out" the lw mids (around 200-400 Hz), which is a common issue in small rooms. The ideal approach is to use REW repeatedly during the treatment stage to make sure that your decay times remain smooth across the spectrum, and that your overall decay time (sometimes incorrectly called "RT-60") is correct for your size of room.

I understand full absorption is best for this size room. Please correct me if wrong.

Yup. The rear wall is the biggest problem in pretty much all control rooms, and needs extensive treatment. It's not uncommon to have treatment that is half a meter to one meter thick, in your size room. However, it isn't just absorption: you do need something in there to keep the high end reasonably lively, but without specular reflections. There are a couple of ways for doing that.

Regarding your questions on monitor placement and room modes, you might these resources useful:

Speaker setup, and the equilateral triangle

Modes, Room Ratios, and Schroeder

And about your floor:

What is a floating floor? How to do it wrong, and how to do it right:

Floating your floor: How and why... and why not.

- Stuart -