44m2 is a reasonable size, but any chance you can make it even bigger? More is pretty much always better for a studio.
The Recording Studio will operate as a rehearsal, recording and mix space for my own bands and productions after hours, and also my office during work hours. The Piano Studio will be used by my wife to offer piano lessons.
Might there ever be a connection? Such as the need to track and mix her piano sessions, or maybe use that room as an additional Live Room for some of your own sessions? If so, I'd suggest including windows between the various rooms, where possible. When I'm designing a studio for a client, I try to think of additional things that might be possible at some point, and make the studio as flexible as possible.
Our house is in a quiet residential suburb in Sydney, and the closest neighbour is 6m away.
As a drummer and muso who likes to play loud, I will need superior sound isolation to allow evening sessions without affecting the neighbours.
OK. Got it: Isolation is priority number one! On which side of your floor plan is your closest neighbor? Try to avoid having windows, doors, or HVAC inlets/outlets on that side of your studio, if possible.
The existing garage slab is 6m x 5.5m, and the extension will be 3.3x3.3, so 44m2 all up.
Can you mark on your layout the locations of the existing slab and new slab? I'm asking that because it occurs to be that it might be possible to have your rooms on individual isolated slabs, which allows you to maximize isolation between them. That might not be possible, of course, but it's worth considering.
For the layout, I addressed the critical need for a good sounding mix environment by creating a decently proportioned symmetrical Recording Studio along the shorter edge of the existing garage.
Basic layout looks good to me!
Recording Studio (acoustic dimension): 5.1 x 3.7m
That's nearly 19m2. Pretty decent. The specs for a "critical listening room" call for a floor area of 20m2 or more, but 19m2 is quite fine too. From your diagrams, those seem to be the final inner dimensions of the finished room? Have you considered doing those inner walls "inside out"? That could gain you another few cm of acoustic size on each side of the room (including height).
I placed a main door directly into the Recording Studio, offset to one side so I can place a drum kit next to it, but leaving room in the corner for bass trapping.
Looks good. Did you also try it with the door swinging the other way, towards the front of the control room? It might work out better for access, furniture, traffic. Not sure, but that's one of the things I always try out in the initial design stages: flip doors around, to see if it might help... or not!
Speaking of doors, is there any chance you can move the main exterior door into the control room to be more centered in the rear wall? That would help with symmetry and make it easier to design/build your rear wall treatment.
A large window in each Studio provides some natural light and a view.
My most critical need is to reduce the sound of loud drums (110db) to a neighbour friendly night time level (40db).
Allowing for an environmental level decrease of ~10db at the nearest neighbours, I will need a Transmission Loss within the structure of ~60db
That is do-able, but its pretty much at the limit of what can be accomplished in a typical home studio. It requires careful design (especially with regards to doors, windows and HVAC), and careful construction, with lots of attention to detail. Your two new friends here are named "Mass" and "Seal". Actually "Major Mass" and "Hermetic Seal"
Therefore I'll build a double stud wall with 25kg/sqm of mass on each leaf around the perimeter of the Recording Studio and Booth, and save some money on less critical areas by building a staggered stud wall around the perimeter of the Piano Studio and Internal Booth wall.
For 60 dB isolation, I'd shoot for more mass on those leaves, and a larger air gap.
I'd also suggest using an initial sheet of 19mm OSB or MDF directly on the studs, then your other layers over that. The reason here is three-fold: Firstly, that base layer of OSB gives you a nailing surface all around the entire building, both inside and out. Very useful. Secondly, it greatly improves the structural integrity of the wall: it adds a lot of strength in sheer, which is something lacking in both drywall and fiber-cement board. Third, fiber-cement board is brittle, and not very forgiving of minor impacts. With that OSB backing behind it, it gives it better support and better chances of surviving a careless hammer blow during construction. Green Glue in between the OSB and Fiber-cement board would help even more in that aspect, as well as improving your isolation. It's not actually something that Green Glue has tested (as far as I know), so it's hard to say how much acoustic improvement you'd get, but it will certainly do something good.
Doing the above and increasing the cavity depth to 18cm, would lower your MSM resonant frequency to around 24 Hz, and give you theoretical isolation of a tad over 55 dB. That's pretty good for a home studio. Yes, it makes your rooms a little smaller, but since isolation is the priority, it's worth considering.
Without the extra mass (using your current plan), your MSM resonance is at 41 Hz, and good isolation only starts at about 82 Hz. Kick drums usually come in somewhere around 70-85 Hz fundamental (depending on size and tuning), so your "thump thump" is likely going to get through a bit to the neighbors. Ditto bass guitars (a six string bass goes down to around 31 Hz).
GraGra wrote:Source of the post • 16mm Fyrechek Drywall
• Green Glue
• 16mm Fyrechek Drywall
• 70mm Studs (+ insulation)
• Fabric Covering
Based on that, it seems that you are considering inside-out construction? That's great, but it also implies that you'll need an even larger cavity depth to get the isolation that you need.
• 20mm Gap
That refers to the gap between the outer-leaf stud frame and the start of the inner-leaf drywall, correct? If so, that only gives you 70mm + 20mm = 90mm for your cavity. Not so good, for high isolation. Or rather, it doesn't change the overall isolation
LEVEL by too much (only drops a couple of dB), but it does greatly change the MSM resonant frequency.
Increasing your cavity depth to 170mm, and adding the extra mass, you get the numbers I mentioned before.
Also, you didn't' mention any insulation in the gap: that's important! Filling the entire cavity with suitable insulation greatly increases the isolation. The difference between an empty cavity and a full cavity can be as much as 20 dB in isolation, and 6 dB at the very least. Make sure your entire cavity is filled.
The Booth will either have a heavy duty sliding glass door or a bifold door- Id prefer bi-fold so I can open it right out for extra space when just jamming, but not sure if I can source one that will also provide a decent level of isolation when closed.
Not really. Bi-fold doors give you very little isolation. I'd go with using sliding glass doors on the booth. Something like this:
That gives you excellent sight lines, good access, and reasonably good isolation too. Those are just typical Home Depot type patio doors. We put those in originally as a temporary measure, until the client could order his final acoustic sliders, but in the end he kept these ones as they did a really good job. Enough for what he needed. Which included this:
I didn't actually design the booth to be used regularly for drums, but he managed to get a decent sized kit in there, and he tells me it worked very well. His place is not too far from you, actually: Lismore (OK, not exactly next door!). Since these are internal doors (not facing the outside world), you can probably get away with a little less isolation. Your need is for major isolation to the outside world, so you could save money like this, by going with less effective but less expensive "ordinary" doors for internals, rather than acoustic sliders which are pretty pricey.
The window in the Recording Studio will be fixed panes of laminated glass 10 and 13mm thick.
How deep is the gap between them?
I'm still trying to wrap my head around the HVAC calcs, but hoping to do a ducted mini split to cover both studios.
That would probably work fine, but have you also considered including your wife's piano room? She might not be too happy when you have a wonderfully cooled, dry studio, and she's sweating in Sydney heat! Adding a bit extra HVAC ducting and silencers to include that other room probably wouldn't be a huge thing, since you'd have most of what you need already for the studio. Worth considering!
I'm hiring a Builder to complete all construction on a budget of $150k AUD.
Does the builder have any experience with building recording studios? If not, he's going to need constant supervision and careful instruction before-hand, since a lot of the typical methods and "short cuts" that he normally uses, cannot be done in your place. He likely isn't aware of the extreme need to keep the two leaves entirely separate, without so much as a single nail joining them, nor is he aware of the need for extreme care in sealing everything, twice over. Typical house construction does not need that, so he won't be used to it if he hasn't done studios before. But both of those are critical to achieving your high isolation goals. Even a tiny crack under a wall or around a window can cost you many, many dB of isolation. Basically, if air can get through, then so can sound. You might want to go around the entire build every evening, after he leaves, and re-seal all the spots he missed, yourself. And check for inadvertent flanking paths, too.
to meet approved development requirements I will need the final ceiling to be 2.4m
I didn't know that Australian approved-development rules set the ceiling height. That's unusual. In the UK, they only set the height of the roof, measured at the eaves and peak, but the inner ceiling height can be whatever you want it to be. Some of the studios I have designed for the UK, we actually dug down many cm to get the floor a lot lower, so the ceiling height could be high without violating the roof and eave height regulations. I'm surprised that Australia sets the ceiling height. Unexpected. I also noted that you have 2.7 m ceiling height on the table of room dimensions, but it seems that was an error and should have been 2.4m, if that's the limit that rules allow.
After talking with the builder, he concluded the effort required to modify the existing framework to lift the roof
What type of roof trusses do you have up there? It might be possible to just modify the trusses in-place, without needing to raise the entire roof.
It seems such a waste, but at least it affords me the option of an even higher ceiling.
Now I'm confused! You said that your regulations require a ceiling height of 2.4m, so how can you go higher than that? Maybe you could publish the actual applicable regulations here, or provide a link: there might be ways to do what you want that still comply with the regs.
The DA also requires that I either have operable windows to allow for ventilation, or undergo another approval process to approve my HVAC plan, which would cost about $2k. I'm sure fixed pane windows would be best option for Transmission Loss, but not sure if its worth the extra expense
Do ALL of the windows have to be operable? Sometimes they only specify that, for example, 50% of the total widow area in the building must be operable. In that case, make the windows in the piano room bigger and operable, and the windows in your studio smaller and fixed.
Worst case, you can buy operable acoustic windows for studios, but they are pricey!
▪ Is there another solution for achieving the required ceiling height?
Maybe, but I'm confused about what your regulations actually say. In one place you said that they require 2.4m ceiling height, so it seems that they don't allow higher ceilings under this regulation?
▪ Is there a significant cost increase in building a ceiling inside out?
slightly higher cost in materials, yes, but mostly it's just the increased complexity of building like that.
▪ For someone with only basic building skills, is demolishing a garage myself realistic?
It's possible, yes, but a hell of a lot of work, and you might also need certification to do that. Check your insurance, too. You might not be covered for personal injury and third-party damages, if you do it yourself.
▪ Are there operable windows available that would achieve the same or similar TL as two fixed panes of glass?
Yes, but not cheap. You could also build them yourself, but that requires some skills and tools that you might not have.
▪ Does my HVAC spec sound somewhere in the zone - Air Volume Rate :500CFM (236 L/s) and Air Flow Rate : 60CFM (28 L/S)
I didn't do the math, but something seems off there.
▪ Most manufacturers list either an Air Volume or Air Flow Rate in L/S, but never both. Have I misunderstood?
Perhaps!
▪ It seems like units in the 6kw range are appropriate for my needs?
Heating/cooling is usually specified in btu/hr, or even "tons". It might be different in Australia. Do you have a link to the AHU units you a re thinking of?
▪ Any idea's about a bi-fold vs sliding door for the Booth?
Answered above.
▪ Any other thoughts or concerns with my design?
Yup! But I'm out of time right now, and it would be better to get these basics resolved first....
- Stuart -
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