Basic treatment for small home production/mixing room

[jaku5]

Hi all,

I discovered this fantastic community via reddit about 6 months ago and was instantly blown away by huge amount of valuable, well explained and science backed information in here. Truely a unique place so thanks to everybody who is making that happen.

I am currently in the process of designing my room. Due to budget constraints my plan is to go with basic treatment and hopefully get a useable space to work in. The room is going to be used mainly for production (sound effects and music) and mixing, would be nice to be able to record some voiceovers and maybe acoustic guitar.

CONSTRUCTION DETAILS:

The room is on ground level, floor is strip footing filled with concrete, wall with window on it is an outer wall made from concrete masonry unit and styrofoam (12 concrete, 8 styrofoam, 24 concrete, 45cm total thickness) and other four inner walls are made from brick (25cm thick). Front wall is next to the garage, rear wall is next to a hall connected with kitchen.

The floor surface is roughly 13.5m2 and ceiling is 270 cm high.

ROOM LAYOUT:

I plan to put the desk so that the window is on my right side when mixing in order to place speakers along the longer wall. I’m also considering flipping it so that the window is behind in case this 30cm deep window cavity turns out to compromise symmetry.

The speakers will be Genelec 8030 with 7050 sub. Though I’m aware soffit mounting would probably be best I could do I don’t feel like being able to construct them properly for now and it also might exceed the budget quickly, so instead I hope to reduce the SBIR issues reasonably by placing speakers, on massive stands, tight against 10cm thick panels and a little bit with speaker cabinet construction.

jaku5-room.png

jaku5-room2.png

SKP file

ISOLATION:

I hope to get hold of some decent meter soon, so I’ll post my results then. The surrounding area is country so there is not much noise apart from occasional rains and aircrafts. Probably the noises from the neighbouring kitchen could be more of a problem. Due to size of the room and the budget constraints I don’t consider doing a proper 2 leaf isolation. Instead I hope to get enough isolation by replacing a door for solid ones and sealing them. This needs to be verified with meter.


TREATMENT:

Same thing as witch meter I will need to acquire a proper mic to measure acoustics of the room. Basic treatment plan is superchunks in three right angle vertical corners (ROCKSONIC SUPER 10CM, 38KG/m3 density, ~78cm across corner), 2 panels on the front wall, behind the monitors, tight against the wall (PT80 80kg/m3, 10 CM), 2 side panels on the first reflection points (TOPROCK SUPER 15 CM 40kg/m3) 10cm gap from the wall, floor to ceiling on the rear wall treatment, with gap for the air vent (TOPROCK SUPER 15 CM 40kg/m3). Hardbacked cloud on the ceiling (still need to figure out the design).

BUDGET: ~1000$

PLAN:

The plan is as follows

1. Rip out the carpet
2. Do the baseline REW test
3. Superchunks and panels behind speakers
4. REW test
5. Rear wall treatment and side panels
6. REW test
7. Ceiling treatment
8. REW test
9. Door replacement and floor finishing
10. REW test



THINGS TO RESEARCH:

Would stuffing up window cavity with insulation and dry walling it is viable option to achieve symmetry? I would like to avoid dry walling it if possible.

How to treat angled wall with door on it?

Is 80kg/m3 too dense for front panels?

Where to best place sub?

Can monitors be placed tightly against panels without causing heating issues?

Given no isolation do I need a HVAC?

Should I be worried about resonance of metal electric heater?

Thanks for reading, I’ll update once measurements are done. Of course any feedback on my plan is more than welcome

[Soundman2020]

Hi there Jakub, and WELCOME!

Wow! Excellent first post! You obviously did your homework and research before posting, and too the time to do a good plan, with detailed SketchUp model. I'm making your thread a "stickie! already, because it's such a great example of what a first post should be like.

Basically you have a pretty good plan. So let's look at your questions:

Would stuffing up window cavity with insulation and dry walling it is viable option to achieve symmetry? I would like to avoid dry walling it if possible.

Just stuffing it with insulation (without drywall) then doing the same thickness of insulation on the opposite wall, would go a long way towards getting some symmetry in the room. The only other option would be to rotate the orientation 90° anti-clockwise, such that the window is then your back wall, and in that case also stuff it with insulation and no drywall. However, that does also mean that your speakers are firing along the shorter axis... but with the dimensions being very similar anyway, and a very small room, that's probably not really much of an issue. Either way would probably be OK. You could do REW tests with the window stuffed using both layouts, and see which one works best for symmetry.

How to treat angled wall with door on it?

I would put a superchunk horizontally across the top, in the wall/ceiling corner, some light but thick insulation on the door itself, and a small poly in the space next to the door, to the left.

Is 80kg/m3 too dense for front panels?

Probably, but I'd have to see the acoustic test data for that specific product to be sure. You need something that has very high coefficient of absorption for the lowest frequency bands. Something around 0.7 or more at 125 Hz. The higher the better.

Where to best place sub?

On the floor close to the front wall, between the speakers probably, but not centered. The way to find the best location is, after you have most of the treatment in place, do several tests while moving the speaker around, to find the smoothest spot. One good way of doing that is to set up the speaker on a tall chair, where your head will be while mixing, play ping noise, then use the REW "RTA" feature to find the best spot by moving the mic around possible locations for the sub, looking for the spot with the best response.

Can monitors be placed tightly against panels without causing heating issues?

Yes. There will still be a gap behind the speakers, because they will be angled inwards towards the mix position, and also there will be a panel of light insulation behind them. That should be enough for good ventilation... you won't be playing them at full power in any case, so the heat sinks won't be getting hot: just a bit warm. But do check them the first few days you are using the room, to make sure they are not getting hot, just to be sure.

Given no isolation do I need a HVAC?

You are going to seal the window air-tight. You are going to seal the door air-tight. There's no other air paths into the room... It's a small room... I think you can see the answer here... Unless you are only going to do very short sessions of just a few minutes per day, then you probably will need at least some type of ventilation.

Should I be worried about resonance of metal electric heater?

Possibly, but probably not. When you have the room partially treated, do REW tests with that in the room and also removed from the room... and also listen carefully with your ears. If it is fixed in place and can't be moved, then do one test with it open to the room, and another with insulation stuffed between the vanes and a thick, heavy blanket draped over it.

Thanks for reading, I’ll update once measurements are done. Of course any feedback on my plan is more than welcome

Once again, congratulations on an excellent first post!

- Stuart -

[jaku5]

Hi Stuart,

Thanks so much for taking time to respond and for all the kind words

Just stuffing it with insulation (without drywall) then doing the same thickness of insulation on the opposite wall, would go a long way towards getting some symmetry in the room. The only other option would be to rotate the orientation 90° anti-clockwise, such that the window is then your back wall, and in that case also stuff it with insulation and no drywall. However, that does also mean that your speakers are firing along the shorter axis... but with the dimensions being very similar anyway, and a very small room, that's probably not really much of an issue. Either way would probably be OK. You could do REW tests with the window stuffed using both layouts, and see which one works best for symmetry.

Probably not a smart question, but I'm not sure if I understood this one correctly If I keep the current layout would I need to stuff the window with 30 cm thick insulation and then add same size 30 cm thick insulation on opposite wall so it would kind of shift middle of the room 15 cm to the right or just fill the cavity and place first reflection panel in front of it and on opposite wall?

I would put a superchunk horizontally across the top, in the wall/ceiling corner, some light but thick insulation on the door itself, and a small poly in the space next to the door, to the left.

Got it.

Probably, but I'd have to see the acoustic test data for that specific product to be sure. You need something that has very high coefficient of absorption for the lowest frequency bands. Something around 0.7 or more at 125 Hz. The higher the better.

These are the specs provided by manufacturer so it looks like it might be ok.

pt80_data.png

The reason I ask is because I already have two panels of those and wanted to know if they could be of any use for this room.

On the floor close to the front wall, between the speakers probably, but not centered. The way to find the best location is, after you have most of the treatment in place, do several tests while moving the speaker around, to find the smoothest spot. One good way of doing that is to set up the speaker on a tall chair, where your head will be while mixing, play ping noise, then use the REW "RTA" feature to find the best spot by moving the mic around possible locations for the sub, looking for the spot with the best response.

Got it, this sounds like fun

Yes. There will still be a gap behind the speakers, because they will be angled inwards towards the mix position, and also there will be a panel of light insulation behind them. That should be enough for good ventilation... you won't be playing them at full power in any case, so the heat sinks won't be getting hot: just a bit warm. But do check them the first few days you are using the room, to make sure they are not getting hot, just to be sure.

Got it.

You are going to seal the window air-tight. You are going to seal the door air-tight. There's no other air paths into the room... It's a small room... I think you can see the answer here... Unless you are only going to do very short sessions of just a few minutes per day, then you probably will need at least some type of ventilation.

OK I see I was sort of hoping this little ventilation grate on the rear wall, wich is leading to chimney would do the trick, but it looks like I need to think again and provide a way for air to get in and out and also create pressure difference so it will actually move.

Possibly, but probably not. When you have the room partially treated, do REW tests with that in the room and also removed from the room... and also listen carefully with your ears. If it is fixed in place and can't be moved, then do one test with it open to the room, and another with insulation stuffed between the vanes and a thick, heavy blanket draped over it.

Unfortunately it is fixed to the wall so I will go with the the latter method.

It will be at least a month from now until I can get measurements done, so I will take my time designing the treatment in sketchup, figuring out the cloud and poly design and ventilation possibilities.

[jaku5]

Hello everyone,

ok, so one more update before I measure my isolation needs and room acoustics (should be this month).

Here is the treatment design in sketchup including Stuart’s advice:

SKP file

jaku5-treatment-rear-2.png

jaku5-treatment-rear-1.png

jaku5-treatment-window.png

jaku5-treatment-front.png

HVAC plan and calculations:

The general plan would be to divide HVAC in two stages. First make a ventilation system now and then save some money during winter and install the mini split once temperatures start to rise (around March).

The room is ~38 m3 so I would need 228 CMH = 3,8 CMM = 134 CFM of an air flow. 25% of makeup air would then be 57 CMH = 0,95 CMM = 33,5 CFM which should be also enough for two people to be comfortable in the room.

For my ventilation needs I plan to go with small HRV unit, 125mm diameter flex duct (which would give me an air velocity of 1,29 m/s) and two silencers (one for intake and one for exhaust) outside the room.

Cross-sectional area of silencer would be 16 cm x 16 cm = 256 cm2 (125mm duct CSA = 123 cm2).

jaku5-silencer.png

Registers could then be 170 mm x 300 mm (effective 300cm2) resulting in 0.38 m/s air velocity.

jaku5-silencer2.png

If I calculate that correctly (thanks to Greg for making calculator and sharing his knowledge here) the entire ventilation system should give me around 25pa of static pressure which would be about all right for the HRV unit I’m considering.

HRV-spec.png

I am yet to calculate my sensible and latent loads to chose right mini-split but I will leave an empty space next to fresh air intake register for the unit.

jaku5-hvac-overview.png

jaku5-registers.png

jaku5-duct.png

jaku5-duct2.png

Cloud:

206 cm x 105 cm frame, 2 cm thick MDF/OSB hard backed, angled 15 degrees. Thanks a lot Stuart for providing that ray tracing tool.

jaku5-cloud-raytracing.png


Again, thanks for reading and feel free to chime in

[Avery]

There are many ways to treatment of small home production room. You can use carpets, floors, mats etc.

[Avery]

You can use different techniques such as you can adjust different sceneries for the beauty of the home. You can also used curtains on the windows of the room.