This is my first post on this forum as a long time lurker and dabbler on this and other audio forums.
My wife and I have recently decided (after a little arm twisting on my part...) to build out one of the spare rooms in our house to be a space where she can work (read: she can actually make money) and I can get back into making music (read: I can pretend to follow my rockstar dreams...).
My wife works in radio and has been picking up work as a voice over for advertising agencies and also edits a few different shows and podcasts. She's getting sick of driving into town for a 30 second voice-over and wants to be able to work from home.
I am an ex live audio guy who has previously dabbled in studio building, love to record, produce and mix personal projects and have taken the odd paid project also.
We recently bought a 3 bedroom house in a suburban area with sub-tropical jungle mixed in for good measure. The room we're converting was intended as a study.
Essentially what we hope to achieve with this studio build is enough isolation so that my wife can record voiceovers without crickets, cicada's and birds as ambience. It is a place that we can personally work in, but would rarely expect clients on premise. As a secondary, but also important goal, I would like to be able to use the room to record acoustic guitars and vocals, mix and comfortably edit in there. I'm not expecting to be able to mix metal at 98dbA past midnight without annoying the neighbours, but I'd like to think I'd get away with 90dbA. We're aiming at a practical and achievable result rather than an ideal one.
The space is 2.4m tall x 2.8m long x 2.4m wide so it's comfortably big enough for a vocal booth, but it's going to be a stretch for everything else.
Acoustic goals:
- good isolation from the outside world
- dry enough for voice-overs
- bottom end trapped enough for mixing
- enough life in the room to enjoy being in there and recording the odd acoustic guitar or electric amp.
I recognise that the dry enough for voiceovers and a bit of life in the room are competing goals and I think if the room has issues with reflections for the VO's then I might mitigate using a mic shield. I can foresee facing the back of the room to record voice and vocals and obviously face forward for mixing. This will avoid the obvious reflection from the front soffits.
At the moment, the total budget for building out the room (no gear) is maxed at $4k AUD.
Ok here's some simple 3D modelling I did pretty close to the measurements for the spousal presentation:
Ok - here's how the room currently sits in the world
- the wall with the big window in it is to the outside of the house
- the wall with a door in it is the only new wall in this project and closes in what was previously an open room into a hallway.
- the wall at the back is our ensuite and the wall at the front is our main bathroom.
- the floor construction is timber floorboards directly onto floor joists
- the ceiling is currently plaster with charlie-fluff (blow-in) insulation on top
I'm going to outline my basic plan here in as logical fashion as I can. So far I have only framed the wall that has a door in it and ordered some MLV and that's as far as I've gotten.
Floor
The current floor is hoop pine floor boards straight onto the floor joists with no insulation so this is a major weak spot for acoustic isolation from the outside world. My current plan is to lay down some 5kg/m2 mass loaded vinyl (3mm thick) over the current floor boards and then layer on that some acoustic underlay and then wooden laminate flooring on top. The plan was to do this before the new wall plaster layers go up so that the new flooring overlaps underneath the wall.
flooring questions:
- do you think this flooring system on it's own will achieve enough isolation for our goals?
- another thought was to add some yellow tongue into the mix (chipboard-like dense flooring material) in between the MLV and underlay for extra mass. It's reasonably cheap, but the floor would gain an extra inch in height. Do you think the extra layer would be worth it?
Rear Soffits
The rear soffits are essentially just a frame to hold acoustic treatment in place and also to hide some ventilation iso-boxes. In the plans I currently have a large QRD and the rest of the frame is full of knauf earthwool acoustic insulation. On the angled sides of the soffit my current thought was to have timber slats to breath some life back into the room and perhaps higher the Q of the rear absorber, but I haven't put any brainpower into working that out yet so it might yet be just fabric across a frame.
rear soffit Q's:
- I have read that it's not great to have a QRD within a certain distance of your ears or a microphone, perhaps this is one of the cases where the room is just too small? Maybe a 3D diffuser could be a better option. I have previously experimented in control room with switching out a QRD with absorption and I really appreciate how a QRD smooths out the frequency response and in my experience cleans up the stereo image so I'd love to keep it if I can.
Front Soffits:
Ok, here the acoustic rubber hits the road so to speak. I would like to try soffit mounted near-fields. This is possibly the most ambitious aspect of the design and this would be the first studio I've set up with soffit mounted mains so there is risk. I do not own any monitors at the moment and I will need to work that out before I construct the front soffits. What I'd really like is passive sealed boxes (no ports), but that seems really hard to find these days especially down the budget end of the market so I'll have to be flexible.
The current plan for the front soffits is to build a hardwood timber frame (for weight and stiffness) and then attach 3/4 inch MDF sheet to the front with the cutout for the monitors. The monitor stands will be free-standing and inside the wall. I am planning to put a small vent in the bottom of the soffits to get airflow up to the monitors and I may possibly install 19inch racks at the bottom of the soffit also. There will be a vent into the ceiling space through an iso box perhaps with a small fan for extraction. Any space remaining in the front soffits will be full of earthwool insulation.
font soffit Q's:
- Am I being too ambitious here? I am confident in my construction abilities and even my practical experience in acoustics, but this is new to me. I hate having to deal with the corresponding bottom end dip from having your monitors off the wall and I don't like ports that are only good at 1 note.
- Any thoughts on sealed monitors that are currently on the market or perhaps used? I don't trust active monitors as much because I know the processing that can go into them to overcome the limitations of the ported design. You can't just shove a sock in the port (I may have done this in the past

Ceiling
I don't have much height in the room so the last thing I want to do is to drop down a cloud. My plan instead is to knock out the ceiling plaster, build a sealed box out of 3/4inch thick MDF that goes 270mm into the roof space, fill it with more earthwool insulation and face with open weave fabric. This should eliminate early reflections from the ceiling and beef up the low-mid trapping in the room.
ceiling Q's:
-anyone see any pitfalls with this approach? Perhaps a single layer of MDF won't be enough isolation from the outside world? I was hoping this would be mitigated by all the insulation. Another thought was to line the box with MLV.
New Wall and Door
The new wall I have framed out with 90x35mm studs like this: You'll notice unlike the CAD design we ended up moving the door frame into the middle of the wall rather than being offset. Other than that it's as per plan.
My plan for sealing up the wall is 90mm thick earthwool insulation and on each side a layer of 16mm thick fyrchek plasterboard, green glue and then standard 13mm thick plasterboard. The fyrchek plasterboard is a much more dense plasterboard than the standard stuff you can buy at the local hardware store. The door we have thankfully picked up from an old radio station and it's a professionally built acoustic door which is solid core and probably 100kg. I've put in a double stud with hardwood to hang it from. Some of their studios are still functioning and we were able to go and listen to how well the remaining doors worked. They didn't save the rubber seals for the old studios so I'll need to figure something out there.
New wall Q's:
- I haven't been able to find a reference for STC value specifically for a 90mm stud wall with 16mm acoustic plasterboard, GG and then 13mm plasterboard so it is hard for me to know just how well this wall is going to do. Anybody have any experience with the 16mm fyrchek?
Existing walls
This is where things get a little funky for me. None of the existing external or internal walls have any insulation (bloody QLD builders). There are two possible approaches I am considering -
1. Keep the existing 10mm plaster and add green glue, 16mm fyrechek, green glue, 13mm standard plaster (adds up to 39mm of plasterboard with 2 layers of green glue).
2. Rip off the existing 10mm plaster, fill the wall with acoustic insulation and then layer up 16mm fyrechek, green glue and then 13mm plaster.
I'm currently leaning towards option 1. The back and front walls will essentially be covered by a soffit filled with insulation anyway so perhaps the gain from ripping off plaster and adding more insulation will be insignificant. The side wall will be mostly covered by soffit except for the window anyway.
existing wall Q's:
Do you think approach 1 will be enough isolation for us to reach our acoustic goals?
Window
The side window is existing and it's an aluminium frame window that seals reasonably. In a perfect world that would not be an opening window, but it is. My current thought would be to add another layer of glass on the inside to cover the entire frame. I might even be able to get laminated glass perhaps 5mm thick. We'd not be able to access the opening window again, but it would be well sealed.
window Q's:
Anyone got any suggestions on how to deal with the existing window?
Thanks for reading and also I'm thankful for such a forum as this.
Look forward to any criticisms and advise.