John Sayers' Recording Studio Design Forum Archive

G'day, this is my first post here, so hopefully I get everything right!

I've been playing around with in-the-box composition for the last few years and want to begin taking things more seriously. I'm using a small, second storey room (I don't want to float my floor!) and want to try my hand at building my own corner traps and broadband absorbers.

Over the last few weeks I've been trawling this forum, Gearslutz and the wider web to wrap my head around the task, but every time I think I'm getting on top of things, the rabbit hole just goes deeper. I've looked at absorption coefficient calculators, room mode calculators and enough DIY guides to make my eyes bleed!

The more I read (especially here), the more I realise that going too dense or not dense enough could solve some problems while creating new ones, ie. controlling the low end freqs but killing the high end freqs. To zero in on a better answer, I bought an ECM8000 and did my best to measure my room, then got stuck into SketchUp to plot the room and how much space I'm willing to sacrifice.

As far as advice, my biggest hurdles are what density insulation will suit my needs best and how to get my hands on it. Being in Australia (Canberra) and not a wholesale buyer seems to just make things even more complicated! Budget is around $1000-1500, but will consider more depending on cost vs benefit. Fletcher Insulation seems to pop up regularly, but I've had a hard time getting any of them to return calls. I looked at Higgins, but their website says the minimum order is 100m2, which is well over my requirements. Bradford Soundscreen was an option, but from reading these forums, it seems that the thicker they get, the less dense they become - it's also been hard to get a clear indication of kg/m3 for different thicknesses.

To anyone who's gracious enough to help me out, I've included models of the room as it is now and a second design planned out with corner traps and absorbers made with 1200x1200 sheets (maximum space I can sacrifice). The floor is carpet, the far and left walls are plasterboard with brick behind them. The rear and right walls are two layers of plasterboard with insulation between. The far wall has a large single pane window and the right wall has a mirrored sliding door - plan is to open the rear end of the sliding door and stack it with blankets, doonas, rags etc.

As far as materials, it's challenging to get calls returned from suppliers who sell higher density insulation, especially to someone who doesn't want a container load, but I recently came across this website who advertise themselves as an aggregator and liaison between shopfronts and buyers.

Lastly, I've included some room measurements from REW using an ECM8000. Hopefully it helps people to assist with density or product suggestions. Happy to provide more if required.
(For those quoting) I'm looking first for advice on density and thickness for common materials like glasswool, polyester and fibreglass.

If anyone knows of suppliers who are willing to sell to non-wholesale buyers, that'd be great too. https://buybuildingsupplies.com.au/insulation-c-1923.html seems to be a good source for options.

My budget is about $1000-1500, but willing to consider more depending on cost vs benefit.

I feel like I'm asking a lot, so a huge thankyou to anyone who can help me out, even if it's just for part of it.

Cheers,

Sam

I've been looking more at local providers and have found a one who supplies some Bradford products that might fit the bill, but again it's hard to find density. Would be keen to hear what you guys think.

http://justrite-insulation.com.au/optim ... 5-6m-pack/
http://justrite-insulation.com.au/sound ... -per-pack/

Hi there Sam, and Welcome to the forum!

(I don't want to float my floor!)

Good ! Because... : http://www.johnlsayers.com/phpBB2/viewt ... f=2&t=8173

and want to try my hand at building my own corner traps and broadband absorbers.

So this project is purely treatment of your room? You do not need any additional isolation at all? No problems with sound getting out? (or in).

but every time I think I'm getting on top of things, the rabbit hole just goes deeper.

Yup! And the deeper you go, the deeper it gets... It's like one of those nightmares where you are running just as fast as you can towards the only exit, but the faster you run, the further away it gets from you, receding into the distance...

The more I read (especially here), the more I realise that going too dense or not dense enough could solve some problems while creating new ones, ie. controlling the low end freqs but killing the high end freqs.

The good news is, that you don't need to sweat it that much: There's a fairly broad range of gas flow resistivity values that will do good things to your room, and it is fairly easy to return the liveliness by using plastic or something similar in front of the traps.

As far as advice, my biggest hurdles are what density insulation will suit my needs best and how to get my hands on it

Bass traps are similar in nature to MSM wall isolation, so the same rules apply: If you go with fiberglass insulation you will need something with a density of roughly 30 kg/m3, give or take a few kg. And if you go with mineral wool insulation, you will need something with a density of roughly 50 kg/m3, give or take a few kg.

To anyone who's gracious enough to help me out, I've included models of the room as it is now

To get maximum "bang for the buck" out of your bass traps, build them as "superchunk" style traps. That means cutting your insulation into large triangles, measuring about 90cm on the adjacent sides, and stack those in the corners from floor to ceiling. Cover that with a frame that has some type of attractive fabric on the front (your choice), and with plastic behind the plastic, to keep the highs in the room while letting the lows through.

The floor is carpet,

Bad choice! That will have to go.

and the right wall has a mirrored sliding door -

Where does that door lead to?

Lastly, I've included some room measurements from REW

Unfortunately, your graphs aren't a lot of use, because of the scales and other parameters you have selected for displaying them. I would need the actual MDAT file. Please upload it to a file-sharing service, such as Dropbox, then post the link here.

I feel like I'm asking a lot,

Not at all! That's what the forum is here for...


- Stuart -

Hi Soundman,

Thanks for taking the time to respond.

So this project is purely treatment of your room? You do not need any additional isolation at all? No problems with sound getting out? (or in).

Correct. I've noticed no issues with intrusive sound or otherwise.

To get maximum "bang for the buck" out of your bass traps, build them as "superchunk" style traps. That means cutting your insulation into large triangles, measuring about 90cm on the adjacent sides, and stack those in the corners from floor to ceiling. Cover that with a frame that has some type of attractive fabric on the front (your choice), and with plastic behind the plastic, to keep the highs in the room while letting the lows through.

Is this a general rule, or just specific to my needs? I had planned to use absorbers with an air gap because building superchunks will significantly increase the amount of insulation I need to purchase. But, if superchunks will be a better solution to my situation, I'll plan it out and see whether I can afford it. If I can't and have to go back to the original plan, will it make that much of a difference?

Where does that door lead to?

It's for a wardrobe in the room. My plan was to open it, then build traps to fit inside it, or just load it with old blankets, doonas, rags etc.

Unfortunately, your graphs aren't a lot of use, because of the scales and other parameters you have selected for displaying them. I would need the actual MDAT file. Please upload it to a file-sharing service, such as Dropbox, then post the link here.

https://www.dropbox.com/s/yybcn9n5zrwfz ... .mdat?dl=0

Thanks again for taking the time to help me out. Very much appreciated!

Still looking for insulation options and came across Bradford Ultratel.
http://bradfordinsulation.com.au/~/medi ... sheet.ashx

48kg/m3 glasswool insulation. Pics are shown with foil backing, but it looks like that's an optional extra.

Whether I can get hold of it though....

Is this a general rule, or just specific to my needs?

It's a general rule, applicable to most situations, but not necessarily all. The general rule is that small rooms need major bass trapping. The smaller the room, the more trapping it needs. But looking at your REW data, your room doesn't seem to be as bad as I had expected. However...

It looks like you have not calibrated REW correctly (using a proper hand-held sound level meter). Or if you did calibrate it, then you ran the tests way too quietly. You should be running them such that the level for each individual speaker is 83 dB, roughly.

Did you have the mic at the mix position, exactly centered side-to-side, at a height of 1.2m above the floor, and tilted upwards at about 60°?

I had planned to use absorbers with an air gap because building superchunks will significantly increase the amount of insulation I need to purchase.

You can probably do that in your room, yes. It looks like it might be enough, but do make it thick, and put plastic across the front, to keep the highs in the room.

But, if superchunks will be a better solution to my situation, I'll plan it out and see whether I can afford it. If I can't and have to go back to the original plan, will it make that much of a difference?

In some rooms there could be a large difference: I'm not so sure the difference will be large in your case, because the current situation doesn't seem as bad as I had expected.

What treatment did you have in the room at the time you did hat REW test?

It's for a wardrobe in the room. My plan was to open it, then build traps to fit inside it, or just load it with old blankets, doonas, rags etc.

That would be useful, yes. But fill it as much as you can with insulation, then add the rest to top it off. You don't need to build actual traps inside: just pile up the insulation and "stuff".

48kg/m3 glasswool insulation. Pics are shown with foil backing, but it looks like that's an optional extra.

It looks like the 75mm thick version with the perf foil face would be what you need. You could add a second layer of 50mm without the foil behind that one, if you need more absorption.

Whether I can get hold of it though....

Have you gone to your local hardware store r building supply store, to see what they have on the shelf right now? There might be something useful.

Anyway, please calibrate REW properly with an external meter, then repeat the tests, to make sure they are done right. If the level is not high enough, you might not trigger some of the modes, so it's best to do it right....

- Stuart -

Hey Samm,

I am going through insulation material blues/learning at the moment too and I'm lucky that http://www.insulfix.com.au are only about 30 minutes or so from me in Cardiff NSW.

They have the full range of Bradford products including Ultratel (48kg/m3) and also Fibretex Rockwool 350 (60kg/m3). So far in person have proven to be very knowledgable and friendly. Their prices also seem to be quite competitive based on my online comparisons.

They have a south coast/southern highlands branch that may be worth contacting. Sure, it's not Canberra but being in the business they may be able to recommend someone local.

Good luck,
Ben