Rear wall lack of symmetry in small home studio

[mattpike1989]

So I have been doing lots of research and think I have laid out my plans to try and treat my home studio. It is a very small and awkward room with the main usable space being 9'6"x9'6"x8'6" plus an alcove/entranceway (where the door) is of roughly 3'3"x2'1". The room will be almost entirely used for synth based work, mixing and occasionally vocal tracking.

My main concern now is that in order to get my listening position into what seems like the most desirable rear 38% position (which is currently an estimate until my measurement mic arrives to test), I am pushing myself close to the rear wall and am concerned about the lack of symmetry there in the room and as a result the treatment.

I am intending on DIYing the treatment to reduce costs and as a result am trying to avoid tricksy panel traps etc.

You can see what I am thinking about going for in this pic

Room 3.jpg

Will this lack of symmetry on the back wall cause me problems in the listening position?

Is there much that can be done about it?

Also the room is (not the nicest) carpet currently and I am considering changing to a laminate wood flooring (sadly not got the budget for a real wood). Will this be of benefit it trying to keep something resembling liveliness in what is inevitably going to be a very dead room or cause more problems than its worth?

I am also intending on putting broadband absorption at the ceiling first reflection points but removed it from image to try and make it less confusing.

I hope I have remembered everything from the rules, it's late here and I have been researching a lot to get to this point so apologies if I have missed something obvious.

Cheers

Matt

[Soundman2020]

Hi Matt, and Welcome!

with the main usable space being 9'6"x9'6"x8'6"

Ouch! That's a square section, so you are going to have some pretty big modal issues. I would ensure that your bass traps are enormous. 24" is too small: make them 36", and also put some in the horizontal corners of the room, not just the vertical.

in order to get my listening position into what seems like the most desirable rear 38% position ... I am pushing myself close to the rear wall

That doesn't make any sense! If you are at 38% of the room depth, then you are close to the FRONT wall, not the REAR wall!!! In a room 114" long (9'-6"), your head should be about 44" from the front wall and 70" from the rear wall.

Also, for that size room, your speakers should be 32" from the side walls and therefore should be only 50" apart (4'2", or 127cm) not the current 73" (185 cm). Your speakers are way too far in to the corners. They are also too far away from the front wall: they should be tight up against the front wall, separated only enough to get the absorption panel in there, which is about 10cm thick.

I would not be too worried about the symmetry problem at the rear: that's the least of your worries in that room. But I would put at least 15cm of thick absorption on the entire rear wall (except where the superchunk is, of course).

I am intending on DIYing the treatment to reduce costs and as a result am trying to avoid tricksy panel traps etc.

Smart move! That room is going to need mostly absorption anyway, so you have the right plan there. Make all of your panels from OC-703. You have the right idea with the side panels, on your first reflection points, but you also need panels on the front wall, right where the speakers are, and you will definitely need a cloud over the desk: make it hard-backed, angle it as much as you can within reasons, and put absorption on top of it, as well as underneath. Use chains to hang it, and make sure they are secure and safe.

Also the room is (not the nicest) carpet currently and I am considering changing to a laminate wood flooring

Definitely! Most certainly get rid of the carpet, since that is damaging your acoustics, not helping, and laminate flooring is a very good surface for a studio.

Will this be of benefit it trying to keep something resembling liveliness in what is inevitably going to be a very dead room or cause more problems than its worth?

Yes it will help, very much, but you will also need to do more to recover a bit of liveliness: cover your bass traps and your cloud with thick plastic, and perhaps even put some strategically located wood slats over the front of the bass traps at the rear, and over the entire rear wall. There might also be other things you'll need to do, but that will get you started.

However, do realize that that room can never be a world-class room, simply due to the size and the unfortunate shape and dimensions. It can be made reasonably decent, but it won't ever be Galaxy.

- Stuart -

[mattpike1989]

Hey Stuart,

Thanks for all the info, I have had a slight change in my situation (in the form of bass leaking into the rest of my flat damaging my girlfriends sanity). I have tried to implement the basics of what you suggested, here is a link to the .skp file on google drive (tried to make it skinnier but ran out of steam).

I would ensure that your bass traps are enormous. 24" is too small: make them 36", and also put some in the horizontal corners of the room, not just the vertical.

I have pushed them up to 85cm/34" which is as big as I can make them within budget/space constraints. Unless you have any alternatives ideas which will be as effective in same space/price region. I have seen people suggesting using lower density insulation or combination of the both but not found specific designs or evidence of the efficacy.

That doesn't make any sense! If you are at 38% of the room depth, then you are close to the FRONT wall, not the REAR wall!!! In a room 114" long (9'-6"), your head should be about 44" from the front wall and 70" from the rear wall.

Also, for that size room, your speakers should be 32" from the side walls and therefore should be only 50" apart (4'2", or 127cm) not the current 73" (185 cm). Your speakers are way too far in to the corners. They are also too far away from the front wall: they should be tight up against the front wall, separated only enough to get the absorption panel in there, which is about 10cm thick.

My mistake there, have set up in the suggested listening position and can already tell how much of a difference it is making pre treatment. Cheers for clearing that up.

But I would put at least 15cm of thick absorption on the entire rear wall (except where the superchunk is, of course).

Again budget and space have slightly limited the amount I have implemented in the design but have got most of it covered.

Make all of your panels from OC-703

I am going to use Knauf RS60 or Rockwool RW3 as OC is too expensive and awkward to source in the UK. Will be building wooden frames for panels, just didn't bother with details in drawings.

you also need panels on the front wall, right where the speakers are, and you will definitely need a cloud over the desk: make it hard-backed, angle it as much as you can within reasons, and put absorption on top of it, as well as underneath. Use chains to hang it, and make sure they are secure and safe.

I am installing a resilient bar system on my ceiling with two layers of acoustic grade plasterboard (not perfect I know but its a budget and space constraint). OSB and other ply seems to come thickest in 18mm boards will that be suitable for the hard backing on the cloud? I am concerned that not being able to screw directly into the joists means I won't be able to use the hard backed design for weight bearing reasons. What would be your suggestion in terms of fixings for the ceiling cloud (will be 4'x4' with 4" RS60 underneath and 2" above)

you will also need to do more to recover a bit of liveliness: cover your bass traps and your cloud with thick plastic, and perhaps even put some strategically located wood slats over the front of the bass traps at the rear, and over the entire rear wall. There might also be other things you'll need to do, but that will get you started.

I have been try to track down 6mil plastic sheeting (you recommended this in another thread) but am finding it more difficult than expected to get thickness info in UK, would any reasonably heavy duty plastic sheeting do? I definitely want to cover some of the traps with wood (if budget permits) simply for aesthetic reasons. What thickness of wooden slats would you suggest? When you say strategic placement, is this in terms of controlling the reflections given?

However, do realize that that room can never be a world-class room, simply due to the size and the unfortunate shape and dimensions. It can be made reasonably decent, but it won't ever be Galaxy.

Thanks so much for the help with this Stuart. I am completely aware of the realities I face in the now. I wish I had known more when we were looking to buy the flat. Either way this room will probably sound better than any I have worked in on a regular basis up until now. You guys are fantastic for keeping this forum running like you do, it's been massive help.

[Soundman2020]

Thanks for all the info, I have had a slight change in my situation (in the form of bass leaking into the rest of my flat damaging my girlfriends sanity).

Not good! Gotta try to fix that...

I have tried to implement the basics of what you suggested, here is a link to the .skp file on google drive

I downloaded that, and cleaned it up a bit for you. Here's the result:

http://spartanew.digistar.cl/SayersForu ... nt-S03.skp

Take a look at the layers...

have pushed them up to 85cm/34" which is as big as I can make them within budget/space constraints.

That's fine. It's close enough.

I have seen people suggesting using lower density insulation or combination of the both but not found specific designs or evidence of the efficacy.

In general, lower density is better at absorbing lows than high density, within reason, but it also depends on the type of insulation, and the application. For example, for damping inside an MSM cavity, if you use fiberglass insulation then you'd need a density of around 30 kg/m3, but if you use mineral wool it would need to be about 50 kg/m3. OC-703 is an excellent general-purpose insulation, that is very useful for many acoustic applications.

Also, it isn't really the density that matters. It's a property called "Gas Flow Resistivity" or GFR. That's what actually governs the acoustic behavior of insulation. But most manufacturers don't test for that, or don't publish the results. Fortunately, there is a rough relationship between GFR and density, so that's why we can suggest different densities. But what we are actually suggesting, indirectly, is different GFR characteristics. GFR is measured in the rather esoteric unit of "rayls MK/S"...

have set up in the suggested listening position and can already tell how much of a difference it is making pre treatment. Cheers for clearing that up.

I noticed in your new SketchUp model that you have flipped your Adam A7X speakers onto their sides: not a good idea. Yes, you do see that in many photos of studios, but that still does not make it a good idea. The reason is simply this: The tweeter and woofer are no longer in the same plane, vertically, so as you move your head forwards, backwards, left, right, you hear different levels and combinations of bass and treble, so you are not getting a clean stereo image or sound stage, and your perception of frequency response and directionality changes, depending on where your head is. The human auditory system is very good at noticing directionality in the horizontal direction (because our ears are out on the sides of our heads!), but lousy at picking that out vertically, which is why most speakers are built with the drivers lined up vertically: your brain can't tell the difference. But when you lay it horizontally, your brain can tell the difference, so it tells you different things as you move your head around. You can lay your speaker down if the room is large and the speakers are far away, or if the speakers are specifically designed to be used horizontally (EG, the Adam A77X), but even then it is better to use them vertically.

So stand your speakers up straight! That will also allow you to get them even closer to the front wall...

I am going to use Knauf RS60 or Rockwool RW3

Do you have links to the acoustic technical data for those products, to check if it is suitable?

I am installing a resilient bar system on my ceiling with two layers of acoustic grade plasterboard (not perfect I know but its a budget and space constraint).

That's fine. It will work OK.

OSB and other ply seems to come thickest in 18mm boards will that be suitable for the hard backing on the cloud?

Either will be fine. MDF will also work.

I am concerned that not being able to screw directly into the joists means I won't be able to use the hard backed design for weight bearing reasons.

Check with the manufacturer of your Resilient Channel, to find out what the safe load is in your application. That will probably be expressed as kg/m2 of ceiling area. So spread the load of your cloud across several different strips of RC, and between several different joists. For example, if your cloud ends up weighing 50 kg, and your RC can handle 40 kg/m2, but you already have it loaded to 25 kg/m2 with the two layers of drywall, then you only have 15 kg/m2 of capacity left, so you'll have to spread the load of the cloud over 3 different channels, or even 4 to be safe. That way, you'd only be adding 10 kg load to each one, and if you spread it even more bu using 2 attachment points on each channel, you'd be down to just 5 kg extra load. It can probably be done, but do the call the manufacturer and do the math.

You might also want to look at using RSIC clips plus hat channel, instead of regular resilient channel. It can probably take a higher load, and will give you better isolation anyway. Don't confuse resilient channel for hat channel! They are NOT the same thing. If you use RSIC clips, then you must use hat channel. If you don't, then you must use proper resilient channel, NOT hat channel.

would any reasonably heavy duty plastic sheeting do?

Yes. No problem. Worst case, you could even go with two layers of thinner plastic.

I definitely want to cover some of the traps with wood (if budget permits) simply for aesthetic reasons. What thickness of wooden slats would you suggest? When you say strategic placement, is this in terms of controlling the reflections given?

18mm thick would be fine, but it isn't critical. This wont be a tuned slot wall, so thickness doesn't really matter. It is only important if you make it into a proper slot wall.

"Strategic placement" is for both reflection and also protection! Try to set them at elbow height. hip height, shoulder height, knee height, show height, and chair back height, to protect your clot from the typical dangers of clumsy people. But also avoid setting them at a height where they would be sending reflections to your ears, or close to your ears.

One other thing I noticed in your model is the air vents: You are DEFINITELY going to need silencer boxes on those! Otherwise the are a direct path for sound to get in and out...

Thanks so much for the help with this Stuart. I am completely aware of the realities I face in the now. I wish I had known more when we were looking to buy the flat. Either way this room will probably sound better than any I have worked in on a regular basis up until now. You guys are fantastic for keeping this forum running like you do, it's been massive help.

That's what we are here for!


- Stuart -