Initial Treatment Idea For An Existing Room. Thoughts?

[CiaranB]

Hi,

Myself and two friends are moving into a new studio space this week, I've been a (thankfully) working engineer/producer for the past few years and I've decided to take the plunge and set up my own room for songwriting, preproduction, overdubbing (mainly guitars, bass, synths, vocals, perc, occasional individual strings/brass) and possibly some mix work as well. Most of my drum tracking will be probably be done elsewhere, although no doubt I'll end up tracking drums here from time to time. I work on a lot of different styles of music from acoustic through to rock and electronica/techno stuff

Not too worried about isolating the room, just treating it so it's sounds good and it's an enjoyable space to work in. I've gotten very used to the accuracy of working in good commercial studios and I'd really love to be able to rely on what I'm hearing.

I've been doing my research over the past couple of weeks and I've come up with the plan outlined below. Big thanks to everyone who posts on these forums. The design ideas and general information, not to mention the willingness to share, has been absolutely invaluable to me while I've been working on this.

I have a few specific questions that I'll outline at the end of the post and if anyone spots anything they see as problem or think could be better done a different way please throw in your two cents, I'm far from an expert and any help would be hugely appreciated. I'll attach some 2D renders from sketchup of the plan as well.

So......

Room Dimensions are L=7.96m W=4.46m H=2.75m

The room is located at the end of the building so assuming your facing the speakers the only adjoining room is to the left. It's currently occupied by an electronica group that I've done a lot of work with. They use it for writing/rehearsing and they're good friends so we can work out any times we might need peace and quiet from each other. Above me is used as storage for a PA company.

I'm in Dublin, Ireland so I'll be using Rockwool RS60(60kg/m3) or RS100(100kg/m3) as appropriate instead of fibreglass panels.

The corners are going to be 848mm faced superchunks

The side walls will have 5 broadband panel absorbers each and the back wall will have 3. The panels are 1800mm x 900mm inside the frame and are going to be 100mm deep with a 100mm gap from the wall provided by the 100mm x 100mm spacers attached to the back.

There are 16 Ceiling clouds sized 1200mm x 600mm based on this design but with the same 100mm thickness and 100mm gap as the wall panels. I've grouped eight of them over the listening postion with back four angled slightly downwards at the back. There's another group of 4 near the back of the room where I envision most of the tracking will happen and the remaining 4 will be evenly spaced across the rest of the ceiling.

There's also two "clouds" straddling the floor-wall join at the front of the room.

....and now the questions....

Regarding the superchunks I'm unsure what the best material is to use for these. From what I've read I'm as well using lower density insulation for this depth but how low should I go? Also if I'm making them out of 'fluffy' insulation rather than rigid rockwool is there any advantage/disadvantage in cutting the insulation into triangles or would I be as well just building a frame and stuffing it with the insulation?

Also not sure what to do with the irregular back left corner or if I'd get away without treating it at all...

Initially I was going to use 100kg/m3 Rockwool for all the panels/clouds but I'm worried that I'll end up killing the room completely if I do. So now I'm swinging more towards the 60kg/m3 instead. Or possibly a mix of the two... 100kg/m3 at the first reflection points and on the back wall and 60kg/m3 for the side walls and remaining clouds?

Another consideration was frk faced panels.. I was thinking they'd be good for the back wall panels and possibly the back few side wall panels as well to lower their useful low frequency absorption point and keep some of the life in the room?

One more question regarding fabric... I seem to be pretty limited for choice here in Ireland. I'd love to be able to get deep blue and deep red coloured fabrics for the panels and clouds so I'm probably going to have to order them online. My knowledge of fabrics is even lighter than my knowledge of acoustics (no pun intended) so any guidelines on what I should be asking for would really help. Is felt a viable option? If anyone can point me towards a specific supplier in Ireland or the UK that'd be amazing.

..................

If you made it this far thanks and sorry for the long post and again any advice, thoughts, opinions greatly appreciated.

Cheers
C

[DanDan]

Hi Ciaran, your plan seems well thought out.
I suggest that you do the very sure things first. SSC's, RFZ side panels, Cloud. Then listen test and add.
Big SSC's is a great start. Here's a very clever way to construct them.
Corner Traps finally finished! - Home Theater Forum and Systems - HomeTheaterShack.com
Those big ones would benefit from using light material. How about RS40?
RS60 should be fine if you are using frames. Do a trial one though. Some of these materials can sag and flop, particularly in a cloud. It is possible to make panels without frames using the much stiffer RS100.
Acoustically either would be fine. If anything the RS100 will absorb a little bit less HF, keeping a minute amount of HF air. I like it.
If you ask them, Readybags will make EU sized bags to fit our 60x100cm panels.
I believe it is beneficial to have FRK on the back of all these panels. i.e. facing away from you.
It should help the LF absorption without hindering RFZ performance.
I don't like the direct specular (behaving like light beams) reflections from FRK. A bit tizzy for me. I haven't seen Rock with FRK but Dublin is bigger than Cork.
Rockwool is not the only game in town. You will probably find Isover High Performance Duct Slabs. 48KG and with FRK and good absorption numbers.
For life you could front your SuperChunks and your framed panels with thin wood laths. If you use a properly random sequence of widths and gaps you will should get some very nice diffusion. Take a look at the traps designs at John Sayers Productions
John designed a Dublin studio. It's on his site. I reckon they would probably tell you where they got their fabric. I saw some really nice fabric recently at Middlewalk studio. Peter mentioned some source in Kildare.
If you succeed in finding fabric locally, please let me know where.
If you are ordering from abroad, Guilford of Maine is the stuff. There are of course EU ones also. Cara. These will be Office or Display or even Acoustic fabrics. Get the Fireproof ones. Might be worth calling Murphy and Sheehy in Dublin. I think GIK sell fabric in the US. Perhaps Glenn will do the same at the UK plant for us Euros?
Send me an email or phone me, details here Sound Sound - Homepage
if you want a chat about any of this.
DD

[CiaranB]

Hey Dan, thanks for the reply, I was hoping you'd chime in. Strangely enough the first project in when I get set up is a Cork band...

Cheers for the SSC build link, I had a similar idea but that looks even easier. I was looking at using Crown Acoustic Roll for the SSCs, I've attached a pdf below. What do you reckon? It'd be a little messier to handle but if it's suitable it'd work out a lot cheaper..

Re the sagging issue it probably makes sense to go for the RS100 in the clouds but I reckon I'll go RS60 for the wall panels. I'm hoping at 100mm thick and in a frame it should be ok. It'd definitely work out cheaper to do it without frames but I'm not sure how I'd mount them with 100mm gap. IDL here in Dublin have pretty good prices on rockwool and I've worked with it before (better the devil you know eh?). Also the slabs are 120x60cm which divides nicely over a few panels into my 180x90cm design.

Re the FRK facing, I can get faced rockwool but it's a special order item from the factory which of course means more money & more lead time. Any thoughts on the 'thin plastic bonded to rockwool' idea? Or possibly aluminium foil? I was thinking of trying this for the SSCs as well.

Might try and get in touch with Peter from Middlewalk about the fabric, I'll let you know if I have any joy on that front.

I like the spaced slats idea but would I not need to angle the fronts? I'm going to do a bit more research into that. Maybe straight up panel absorbers for the the RFZ and back wall and angled slat absorbers for the rest of the side wall panels?..... I believe that's a can of worms we've just opened. ...Although that is why I came here.


Cheers
C

[DanDan]

The Crown Acoustic Roll should work fine. Construction could be difficult though. I always end up with fiberglass for rigidity and lightness.
I bet IDL have those Isover panels. If they are available without FRK they would be ideal for SSC. I remove the FRK but it's a nuisance.
The same panels would be just fine for your FRK fronted spots.
AFAIK nobody has tested FRK or other membrane in front of an SSC yet. It seems like it should work very well. If you do that it would be very useful to us all. I can help you with the testing.
Simple brown wrapping or craft paper is probably the best. I think plastic and aluminium will have an irritating sound.
The slats do not need to be angled. The alternation of gaps and reflective strips is a diffusing system. Particular sets of numbers randomise the effect frequency wise. Guess I will have to look it up and give you the special numbers....

Best, DD

[Glenn Kuras]

Might be worth calling Murphy and Sheehy in Dublin. I think GIK sell fabric in the US. Perhaps Glenn will do the same at the UK plant for us Euros?
Send me an email or phone me, details here Sound Sound - Homepage

We can send GOM over to the UK, but honestly the Camira Fabrics we use there are pretty much GOM and are fire rated.

[DanDan]

Thanks Glenn. Just found this yesterday. Camira is distributed in Ireland by
Fontington Fabrics

DD

[Glenn Kuras]

Originally Posted by DanDan

Thanks Glenn. Just found this yesterday. Camira is distributed in Ireland by
Fontington Fabrics

DD

Good to know.

[CiaranB]

Finally got the keys to the new room. As I said in my first post the room next door is going to be used by a band I know well as a rehearsal / writing room. The problem is the stud partition wall is pretty much a waste of time, it's just a stud frame with drywall either side and no insulation in between.

It was an industrial test building of some description beforehand so the main frame of the building is fairly solid. The four walls surrounding our two rooms are brick, we have a shared concrete poured floor and concrete slab ceiling. There's a steel girder running along the divide between the two rooms. The existing partition is built up to meet the bottom of the girder. I've posted some pics below.

I've been frantically reading around the forums and my plan thus far is to pull down the drywall from my side of the partition fill between the studs with rockwool then build another stud wall filled with rockwool and put one or two layers of drywall up. That would leave me with ...

Drywall+steelgirder---Rockwool---AirGap---Rockwool---DoubleLayer Drywall

... which hopefully approaches the scenario in the last picture below.

I know there's going to be flanking noise and this is far from ideal, I'm just wondering if this is going to worth doing at all? How much sound can I realistically expect to block?

Would it be worth my while to cut the concrete floor? The only place I could realistically do this would be between the two partitions (I'm on the ground floor, there's no basement)

I should also say the band next door have no drummer so while they do want to be able to rehearse at a decent volume they don't always have to.

Any advice or thoughts are really appreciated, I'd love to put the wall up this week but I keep thinking 'fools rush in'

Thanks
C

[avare]

Originally Posted by CiaranB

I know there's going to be flanking noise and this is far from ideal, I'm just wondering if this is going to worth doing at all? How much sound can I realistically expect to block?

It the best you can do without getting into major reconstruction.

How much will it block is hard to answer because, well, I don't understand what you are looking for. Any variations in construction from tested assemblies, which is where true performance data comes from, will affect the isolation. In broad general terms, greater than 50 dB from 250 Hz and higher. See IR 761 pdf pages around 348. Notice the effect of changing the type of insulation! Everything has an effect.

Would it be worth my while to cut the concrete floor? The only place I could realistically do this would be between the two partitions (I'm on the ground floor, there's no basement)

Hard to answer. Sound will still flank araound the cut betwen the rooms. NOt a very technical answer, but if you can do it without undo hardship, do it.

Good luck.

Andre

[CiaranB]

Thanks for the swift response and the great link.

I'll look into how tricky it'd be to cut the slab. If I can achieve anything approaching the numbers mentioned I should be ok.

I'm not looking for total isolation I just want to able to edit and record non critical loud sources like elec guitars while they're rehearsing if I need total silence I'm sure I can work out times with the band.

Thanks again... off to the builders supply yard

C

[DanDan]

How much gets blocked is very much related to how perfectly the new stud/wall is implemented. Both leafs of it need to be airtight, including around pipes, switches, sockets. The bigger the gap the better. The stud system floor and ceiling plates needs to float. Neoprene or such. If the floating and decoupling is effective there is hardly a need to cut the slab.
The insulation in the gap should be light, not dense. The gap should be fully filled, but not compressed in any way. Make sure it is stapled or somehow suspended, otherwise it will gradually descend, ruining the performance.
Heres some construction details pertinent to this side of the pond. Note the performance of the Steel studs. Party Walls & Solutions
Gypsum Ireland have similar products.
I've been rehearsing with a band here lately. Electronic drums, Pods. That's the way to go.....
Good luck with it,
DD

[CiaranB]

Hey Dan, thanks for the reply...

I've a question re the decoupling of the stud wall from the floor and ceiling...

Obviously I can lay a layer of neoprene or equivalent top, bottom and sides but I need to secure the new stud to the floor and ceiling with spring nails so that it's structurally sound... If these go through the rubber and into the floor won't that recouple the stud with the structure thus negating the rubber barrier? Or is the neoprene just to fill any gaps created by the unevenness of the floor/ceiling?

Please let me know if I'm missing something.

C

[DanDan]

I have often pondered that one myself. One could use screws with rubber sleeves. Or perhaps lengths of wood at each side of the plate, holding it in place. I don't have much building experience, practically all of my activity has been remedial. I believe the steels studs provide a degree of decoupling themselves. However I hope some experienced builder jumps in here. Do you have Rod's book? I do, and could look it up for you.
You would probably find a decent answer by searching here or johnlsayers.com or studiotips.com

DD

[CiaranB]

I've ordered the book but no sign of it yet so if you could look that up that'd be brilliant. I've not had great luck searching this or the Sayers forum re floating walls. I'll check the studiotips one now.

I've just pulled the one layer of drywall off the existing partition (very satisfying I must say But unfortunately the other layer is not perfect there are several small holes. Would it be ok to patch these holes by placing another layer of drywall against the existing drywall in the affected stud cavities and caulking around or would I be better screwing it to the studs through the existing drywall from the outside of the wall?

C

[DanDan]

Hi Ciaran, I have skimmed through a few books here. No detail on the floor and ceiling plate. I guess if you drill holes, use a rubber sleeved screw or concrete nail, it has to work. Why not PM Rod and ask him to join in here. Everyone building must have to answer that floating detail.
I don't follow the other question. Holes need to be airtight sealed and the missing mass layer replaced. There is a technique where a piece of card or wood is placed inside. A piece of thread or string pulls it tight to the hole temporarily. Layers of plaster or filler are then built up.
DD