John Sayers' Recording Studio Design Forum

Thank you Brien - that's REALLY helpful.
I'll render wall 4 - the brick wall.
And fear not! There is a ventilation system planned...

May I ask - just on that wall 1 - where I have brick pillars on the retaining wall - with big gaps in between - would you plasterboard between these/over these...or brick up the gaps and render over the top?I presume there's no need to touch the retaining wall as it has solid earth behind it!

Yes - this room was an attempt by my builder at building me a practice room - but the fact that everything was coupled - including the ceiling meant that noise transfer was just too great. And because of how it was done - the three leaf effect required a strip/rebuild..not just an 'add more'.

And as you say - the worst place was directly overhead - in our living room. Alas the builder was not a sound expert and just put up extra plasterboard..and I was too focused on building bedrooms for the baby etc to do my research! I have now reorganised everything so that I can make the space we need before the baby is born late Feb....and finish the music room at whatever pace is necessary!

(Thank you for the comment on internal dimensions too - noted!)

And thanks to you too Stuart - I have asked an engineer to confirm the spacings I need between my bearers on the inner room to support 3 layers of 16mm plasterboard!

LATE NEWS - I have my answer from the engineer: 90*45 mgp10 rafters (ceiling joists) at 450 centres carrying 40kg/m2 can span 2600mm - so I can use 90x 45s (the Aussie 'equivalent' to a 2x4) for the bearers and I'll keep my 2.4 head room....yeay! Though I might put the centres at 300 so a) Ive got more to screw to and b) if I need a 4th layer of plasterboard, I have the carrying power above!!

I would backer rod the joint and use a high quality caulk aimed at concrete or weather-proofing brick or morter or concrete. But I would have to see the joint first.




A three leaf requires multiple air spaces...like two air spaces to be a 3 leaf. It takes a mass/an air space/ a mass/ an air space/ and a final air space mass with no hard connection between any of the air spaces or the mass...or then it becomes a couple assembly



Well, adding mass directly to the underside of the upper floor assembly is part of the project. And will always be the weakest link so you have to treat it like a wall assembly that just happens to be over your head horizontally.



A 2X4 for such a small span could have been resolved right here, had I known what the span, the outside dimensions of the wall to wall assemblies would be, were. What did that engineer cost you?


But the layout is 406mm centers not 460mm and reducing it will gain you nothing.

_________________
Brien Holcombe
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Sound: You can't stop it, you can only try to contain it.

Hi Brien - and thank you.
Here's a pic of one of the voids I'm talking about - I'm assuming that I should brick them up as all your comments thus far have indicated that brick is a pretty good sound insulator. It may be a bit tricky in a couple of places - but if I get as good a fill as I can with the bricks and then fill any gaps/joins with a good caulk/ backing rods, I presume that would be better than just using plasterboard?

(And don't worry about that engineer advice - it was free! So I'm very glad you're happy with the numbers too!)

All the best.

P

Instead of bricking the voids up, why not use them as deep bass traps, or absorbers? Perhaps they need a lining of drywall inside ans on the ceiling to realize this.

_________________
Brian
As you slide down the bannister of life, may the splinters never point the wrong way...

Thanks Brien -
You suggested not just bricking OVER the voids but on using the space as bass absorbers...
And then mentioned using drywall etc.

Can I just check this....

You are suggesting essentially creating a 'box' in the wall of the outer leaf (with plasterboard)
And then this will mean having a smaller 'box' in the wall of the inner leaf that 'hangs' in that outer leaf box.

Pls see my picture...

If I have this correct....may I ask
a) what kind of size the box in the wall of the inner leaf should be...
b) Whether I should create one or two (assuming there is room for two at the size you suggest
c) whether the 'box' in the outer wall should be made of brick wall/ drywall ceiling (to leverage brick's superior ability to stop sound travelling into the house) or all drywall. Remembering my principal goal is to practise the trombone down there without the sound carrying into the house/ over to the neighbours!

Thanks again Brien. Your guidance is very much appreciated!

P

Just a random question as the vendor has no details...can anyone tell from the picture what these acoustic panels are?
http://cgi.ebay.com.au/ws/eBayISAPI.dll ... FP:AU:1123
Thank you
P

Frequency specific Helmholtz panel

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Brien Holcombe
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Sound: You can't stop it, you can only try to contain it.

Yup. Perforated panel, tuned to a specific frequency or small range of frequencies. Probably not too useful to you unless your room has roughly the same issues as the original room those were designed for.

- Stuart -

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I want this studio to amaze people. "That'll do" doesn't amaze people.

Thank you both for your comments on the panels....

I've read more on the forums about bass traps - and can see most refer to large 'pads' that get placed in corners of the room.

Are you able to tell me -referring to that picture I've put above) how you're thinking using that void behind wall 1 might work as a bass trap- I'm thinking about what I'll need to construct in the framing of the inner room at inner-room-wall-1.

Thanks again.
P

Absorption is one form of bass trap, yes. Probably the most common. But there are other ways of dealing with bass too, such as panel traps, hangers, and Helmholtz resonators.


- Stuart -

_________________
I want this studio to amaze people. "That'll do" doesn't amaze people.

Thank you - so may I ask - in that picture about 5 posts up from here - have I understood what you are describing correctly when you suggest I don't just brick over the void in wall 1? The picture is showing an an in wall cavity in the inner room wall 'suspended' in space into the cavity in the outer room wall?
All the best.
P

Perhaps even easier, line them with insulation, fix an insulated panel over the opening including a slot cut as a port, and fill the void with hangers!

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Brian
As you slide down the bannister of life, may the splinters never point the wrong way...

Hi - just a quick question now bub is born and I'm back on the build. Can the insulation wool btw the outer leaf and inner leaf touch both leafs - or should it be outerleaf-wool-airgap-innerleaf?
Thank you
Peter

It can touch, as long as you don't jam it in. In other words, "touch" is the operative word. ONLY touch. If you jam it in, you run the risk of creating a flanking path. And in any event, if you compress it more than just a little bit, then you change the acoustic properties.

- Stuart -

_________________
I want this studio to amaze people. "That'll do" doesn't amaze people.

Thank you Stuart!

PS Brian - when you said in your post 3 up from here 'Perhaps even easier, line them with insulation, fix an insulated panel over the opening including a slot cut as a port, and fill the void with hangers!' - was the 'hangers' bit a joke (i,e. a wardrobe for loud clothes) or something technical!

Best P