John Sayers' Recording Studio Design Forum Archive

Hi Everyone,

I’m starting up a recording on location service in the UK (hoping to start trading in September). We have just acquired this room in an old Mill. The room is quite cheap as we can’t afford much at the moment which is why it’s not totally ideal, but the walls are all soundproofed properly as the building is used for DJs/other mixing engineers. We're planning on using this room as our mixing room, and a place we can eventually take clients to hear their final mixes.

Below is a picture of our room with nothing done so far, which is why it looks pretty grim! Firstly we’re going to paint the place, rip down the current acoustic treatment and start from scratch. We are making some DIY acoustic panels and bass traps following Bobby Owsinski’s tutorials found on Lynda.com, but the biggest issue is the window.

Because it is an old mill, it is a listed building and therefore the window can’t be upgraded to double glazing and there are very small gaps in the window (this also means we can’t make structural changes). We’re lucky that the street is very quiet and there is little traffic, but obviously we need much better isolation. We’ve already talked to the owners of the building to try and get some patching up work to remove the little gaps in the windows, but we feel we need to do something more to improve the isolation. We were wondering whether anyone had any ideas as to what we could do? We thought buying an extra window pane that we could somehow put across in front of the window to give a double glazed effect, or even see if we can board it off altogether. Whatever we do, we need to be able to put the room back as it was when we got it structurally, so take out any glass etc. we may put in. Also, any other comments on what we may be able to do acoustically would be great, the dimensions are: H:273 cm, Width: 417cm, Length: 409cm - length is wall with window (not ideal as nearly square but the walls are varied in length slightly and so aren’t completely parallel – best we could find for our budget). The walls are thick brick walls (as you'd expect in a mill building!). The floor is apparently concrete, but has a pretty thin carpet laid down. Not sure what we can do about changing that though. The door is fairly thick and sealed quite well. The door has a metal sheet with dimples in it on each side. We propose to build bass traps in all 4 corners and have acoustic panels on wall behind speakers and on the back wall as well as clouds. In the room we will hopefully have a sofa at the listeners end, but apart from that and the obvious (desk, monitor stands, desk chairs etc.) that's it. You can't see really in the picture but there are a couple of metal poles that go along the ceiling which we're hoping to use to hang the clouds from.

Thanks in advance for any help!

Dave

Edit: This is what I was planning on using for the panels/bass traps - I'm from UK and have found it difficult to find Owens Corning 703. http://www.ebay.co.uk/itm/Rockwool-Acou ... 1270998268. I was thinking the 70mm to follow the 2 inch suggestion on Bobby Owsinski's tutorial. Would you recommend this?

Sorry forgot to attach picture - here is a panorama of the room!

rip down the current acoustic treatment and start from scratch.

Yup, sounds like a good idea! It's hard to be sure from the low-res photo, but that current "treatment" looks suspiciously like egg cartons... ummmm.... Or if not egg cartons, then maybe very thin sculpted foam? Either way, certainly not what that room needs!

but the walls are all soundproofed properly as the building is used for DJs/other mixing engineers. ... but obviously we need much better isolation.

I'm not sure I understand: If the place is already "soundproofed properly" up to DJ level, then why do you also "need better isolation"? Are you planning to be even louder than a typical DJ?

We are making some DIY acoustic panels and bass traps following ... tutorials found on Lynda.com,

Are you SURE that's what you need? Where is the design for the studio? What is the purpose of the room? How did you determine that 2" 703 absorption panels is what you need? Where is the acoustic analysis? What about bass traps?

I guess I'm giving away that I'm not at all convinced that a handful of simple absorption is the correct treatment for that room...

H:273 cm, Width: 417cm, Length: 409cm - length is wall with window (not ideal as nearly square but the walls are varied in length slightly and so aren’t completely parallel

As you say, very close to square, and red flags are waving all over the place: You will have some pretty ugly modal issues in there, particularly at around 41 Hz, 75, 83, 92, 104, 112, 124 and all of the harmonics thereof. Those are the frequencies where the modes lie practically on top of one another, and sadly it turns out they are not just axial modal issues but also both tangential and obliques are doubled-up. So it doesn't really matter if the walls are slightly off parallel: the modes will still be close to each other, and still be an issue. That's not a happy picture. I would strongly suggest changing either the length or the width of the room.

but has a pretty thin carpet laid down. Not sure what we can do about changing that though.

How about the obvious and very necessary course of action: take it out and throw it away! Carpet is NOT what you want in a studio. If you are on a tight budget, then after the carpet is gone, just clean up the concrete floor and leave it like that: you don't need anything else, and concrete is a great floor, acoustically. Nothing better, in fact. However, if it is bad shape (cracked, crumbling, etc.) then that might not be possible. In that case, you'll probably have to do something to level the surface, then lay laminate flooring on top of it. But "leveling the surface" probably involves pouring leveling cement, which you might not be allowed to do, if the building is heritage-listed.

but apart from that and the obvious (desk, monitor stands, desk chairs etc.) that's it.

Ahhh! Based on that, it seems that this is going to be a control room. Great! So the mystery is solved...

it is a listed building and therefore the window can’t be upgraded to double glazing ... We were wondering whether anyone had any ideas as to what we could do? We thought buying an extra window pane that we could somehow put across in front of the window to give a double glazed effect,

That is one option, yes, but the biggest and most important questions here are: How much isolation do you have right now (in decibels) and how much do you need (in decibels). You say it is already isolated well, but how well? What level do you have right now? And you also say that you need "more", but you need to put a number to that. The ONLY way to determine what you need to do to isolate that room properly, is to start out with objective numbers and an objective goal. All of this can be calculated from your target isolation, so that should be your very first order of business, before making anything or building anything. Only once you know what the target number is for isolation, only then can you start looking at building materials and techniques that will allow you to get from where you are to where you want to go. It might well turn out that an extra pane of glass correctly fitted will be all you need, but it might also turn out that you need to build a complete "room-in-a-room" isolation system. You'll never know which of the two is the right path for you, until you do the tests, do the math, and come up with the numbers.

We propose to build bass traps in all 4 corners and have acoustic panels on wall behind speakers and on the back wall as well as clouds.

That's a good basic plan for treatment, but it won't do anything at all to improve isolation. Those are two entirely different and unrelated aspects of acoustics. Isolation is one thing, and treatment is something else entirely. So don't do any of that until you first solve the isolation problem. And even then, don't install any treatment in the fully isolated room, until you first do a complete acoustic analysis with REW. Then add the treatment, and do another test with REW. That way you can see what you accomplished with your initial treatment, and what still need to be done for the next round of treatment.

This is what I was planning on using for the panels/bass traps - I'm from UK and have found it difficult to find Owens Corning 703. [ link to Rockwool RWA45 Acoustic Insulation Slabs ]

Those should work fine for some of the treatment, but where to you plan to use it? You need different types of acoustic panels for different purposes. Bass traps need less dense insulation, panels meant for mids and highs need to be more dense, and panels for just highs need to be very dense. What is the density of that mineral wool you are looking at?

I was thinking the 70mm to follow the 2 inch suggestion

70mm is nearly 3 inches. You'd need the 50mm stuff if you want to do 2" panels: But whereabouts in the room do you plan to put such thin panels? For what purpose? First reflection points normally need to be thicker than that, the rear wall needs to be MUCH thicker, and bass traps should be superchunks in all 4 vertical corners plos some of the other corners, for a room like that.

But before doing any of that, I'd really suggest that you should get our your sound level meter and do some real-world testing in and around that room, to determine how much isolation you are getting right now, and how much you actually need, total.


- Stuart -

Hey Stuart,

First of all, thanks so much for such a thorough, and quick reply!

Yeh the current treatment is acoustic foam stuff, which is pretty ugly and I'm sure not too useful.

Regarding the isolation, I probably didn't make myself very clear. The interior walls are well isolated, we have a DJ next door to us and we don't hear from him. The building used to house a nightclub so the building had to meet a lot of isolation regulations as residents also live upstairs. The only isolation problem for us is the window in our room. A lot of rooms that the DJs use are in the inside of the building and therefore don't have the window to deal with.

Yes again I wasn't clear enough early on in the post - it will just be used for a control room. I also seemed to mix up isolation and acoustic treatment too much. The panels and bass traps will simply be for acoustic treatment, not for further isolation as I know they don't achieve this. Got a bit ahead of myself I think.

Good suggestion r.e. carpet - I will have a chat with the building manager and see what he says about us ripping out the carpet. I'm sure if we can put it back somehow when we leave there won't be a problem but we'll see how easy that would be, but I very much doubt laying doubt levelling cement will be able to be used in the building unfortunately.

I will try and get hold of a decibel meter, although I'm not familiar with using them so not exactly sure what to do, but I'm sure I will work it out to give you an idea. Another idea I had, as we're not sure we can afford a full "room in a room" isolation system, is to build one wall down the window side (as long as it can be removed when we leave). This means we can decrease the width to 3.5m or so (obviously customisable). I'm not sure how easy attaching just 1 wall will be though? I'm not very experienced in construction but have a friend that has done quite a lot of building work. I'm not sure whether he knows how to build the kind of wall I would need so would need to find some plans or something to show him.

Yeh I agree - we definitely need to sort out the isolation problems first. In terms of acoustic panel materials, unfortunately the density of that wool isn't immediately obvious to me on the ebay page, not sure if you can see something? The 2 inch thick panels were just suggested by Mr. Owsinski on his studio setup and acoustics course, to be used on the side walls and ceiling. So I guess I was just following his tutoring on that side, same with the rockwool where he just said get some RWA45, no more detail.

EDIT: From a bit of research - it looks like Rockwool RWA45 is 45kg/m3 There is also Rockwool RW3 which is 60kg/m3.

I will try and get some kind of meter in the next few days, the best I've got is my mobile app meter at the moment which I presume isn't much use!

Thanks again, and will let you know when I can get the sound measurements,

Dave

Got a few bits a bobs that should help a little.

Here is the panorama I sent above but chopped in 3. The reason it was so difficult to see is because it was a big panorama I resized to 730 or so to meet the regulations, so hopefully you'll see these better

Here is a picture of the ceiling showing the poles etc. I was talking about.

Here is a rough sketchup for the idea I had (Sorry - I'm awful at using the software, but hopefully it's useful in some way).
As you can see, on the picture 'right wall' and on the sketchup, there is a little bit sticking out about 10cm deep, and roughly 20cm high on one of the walls at the bottom. I don't know how much trickier this will make building a potential wall. Also the bits and bobs in the roof as well as the light will inevitably cause some more issues as I'm not sure if we can remove any of these.

Thanks!

Dave

Hey again,

I've done a little more work on the sketchup:
I've more accurately measured the desk/chairs/speakers to how they will be, and moved the partition wall door to the centre for easier access.

Question about the wall if I were to build it - is there any way of building a wall that can be taken down with no evidence of it being there, and ideally (but not necessary) be able to use the wood from it again if I move somewhere new? I don't think I will be able to drill into the floor or anything. Don't seem to be able to find any plans or advice on what kind of wall would allow this. I've moved the outer wall in a bit, because, from my un-knowledgeable look, the room modes would be better with the room being 4.09 x 3.35 than 4.09 x 3.17. Is this right?

Been looking at the bank a bit and now realise my budget for acoustic treatment/building wall/painting etc. is around £700-£800 max. Obviously less would be fine by me

Thanks to anyone that helps!

Dave

Hey,

I'm wondering whether this should now be moved to the studio design or construction forum? Not sure it's in the right place here!

Thanks,

Dave

I'm wondering whether this should now be moved to the studio design or construction forum?

Done! Now under "Studio Design"...

- Stuart -

Done! Now under "Studio Design"...

Great, thanks Stuart!

If anyone here has any useful comments or answers, please let me know. Sorry to post a few times in a row - here is the plan I made for the stud wall. At the moment this doesn't include the door frame. I wasn't sure how best to do the door and where best to put it. Obviously sealing the wall will be made trickier due to the pipes on the ceiling, but I was also confused at how people build the door frame with staggered stud walls. Any help would be much appreciated. I'm hoping to run by all the plans with the building owner this week and order the materials soon to get started on the project, so if there are any glaring errors then it would be great to know
Cheers,

Dave

If you are doing staggered studs, I would go with 60 cm OC spacing, rather than 40 cm OC, as you show. You lose a lot less wood, and it also improves low frequency isolation a bit.

For the door frame on staggered stud, you only really have space for a single door there (rather than the usual pair of back-to-back doors), so use 2x6 framing for the door rough opening. And since the door has to be massively heavy, use three studs on each side to make up the doorway: one jack stud (with the corresponding cripple above the header), and two full length studs. You can build up your own door by starting with at solid-core blank, then adding a couple of layers of 16mm MDF to get the mass. Take a look at how Rod shows it, in his book. And if you don't have his book, now would be a good time to get it!

Also, you show 12.5mm drywall on the plans, but that is no use: too thin, too light, too flexible, bad resonant characteristics. Use only 16mm drywall.


- Stuart -

Thanks Stuart!

You can build up your own door by starting with at solid-core blank, then adding a couple of layers of 16mm MDF to get the mass.

Unfortunately, I'm having little luck finding any decent looking solid-core blanks online in the UK . Not exactly where I go for them? Also, it seems to be that everywhere I look is 15mm for both MDF and plasterboard (they both have variants, for plasterboard there is 12.5, 15, 18) but no 16! Is this slightly different over here or can you not get 16mm in standard online stores? Not sure what to expect £-wise for this, unfortunately budget for the door is only £150-200.

Take a look at how Rod shows it, in his book. And if you don't have his book, now would be a good time to get it!

I've ordered it, looking forward to it arriving, should hopefully be in the next couple of days! Luckily just spoke to the manager of the building today and he said the wall is ok to build and that I can rip out the carpet and replace with laminate flooring

David

Unfortunately, I'm having little luck finding any decent looking solid-core blanks online in the UK

Do you have that book yet? ("Home Recording Studio: Build it Like the Pros") If not, then buy it: Rod shows how to build your own doors....

Also, it seems to be that everywhere I look is 15mm for both MDF and plasterboard (they both have variants, for plasterboard there is 12.5, 15, 18) but no 16!

15mm is fine, but 18mm would be even better.

just spoke to the manager of the building today and he said the wall is ok to build and that I can rip out the carpet and replace with laminate flooring

Excellent!

- Stuart -