John Sayers' Recording Studio Design Forum Archive

I've got a few questions about my studio design. I'm hoping to be able to isolate it enough so one can play drums there at night (a full band would be even better )

The room i'll be building in is at the ground floor, vinyl on concrete.

Room height is 2,55 m.

Neighbours:
- North: a family (but noise friendly though)
- South: Office (compter guys with musician-type working hours)
- east/west: a few meters until next house...

The carpenter wanted to lower the ceiling and build single stud walls with 2 layers of gypsum and just "step-sound-sheet" (10 mm dense rockwool I think) on the floor, but I do not believe that it will bee 24/7 friendly.

So I'm seeking advise to build a 24/7 room:

I've been thinking around using single studs since this will eat less space and be cheaper, so is it possible to get that kind of isolation with single studs, or do I have to use double?

With double studs (2x4"), what about turning them 90 dg. so they become kind of 2x2", will this reduce the stc drastically?

What about turning the 2x4 used for floor and ceiling?

Does the "only gypsum on one side of the wall" rule apply to the whole construction or just the walls facing other studio walls?

Will probably have a million more questions later, but will ask a few at a time and reading some more on this forum.


Thanks

HansP.

Han, from your questions it doesn't sound like you've read this thread yet -

http://www.johnlsayers.com/phpBB2/viewtopic.php?t=598

I'm pretty short on time today (as usual) so if you could read the basics of wall soundproofing on the first page of that thread, then come back with whatever questions you still have, it would help me quite a bit - thanks... Steve

Hi Hans,

There is a ton of info on the forum about STC vs different walls designs.

I don't think 1 single wall will do what you want it to do - 24/7 space.

I just tested the sound proofing on my studio-in-progess. Drums played as loud as possible and les paul played well beyond the thresh-hold of pain. Immediately outside the building - can hear the drums very slightly. 10 feet away - nothing can be heard and that was on a quiet still night.

The walls - room within a room. Outside walls plywood, then between the outside wall studs - roofing felt + 5/8 drywall, then 703. Inside wall - 2by4 stud wall, 2 layers of 5/8 drywall on the room side (3 layers around the drums) - 6inches of fluffy insulation in the space between the walls (in addition to the 703). Lots of caulk! - Ceiling - 2 layers of 5/8 on Resiliant channel. The floor is concrete & the walls have no specific isolation from the walls.

With a single wall with 2 layers of 5/8 then I think you'll hear the drums enough to piss off the neighbors.

Thanks for your replies,

I have infact read most of the thread you directed me to Steve, but I can't seem to find the right answers for my questions, guess I have to read some more before I ask more questions.

Andrew; your design looks interesting, might be just what I' looking for!
From what I understand, you don't have any floating floor under the the walls, is this right?
Love to get some drawings/plans of your design.

HP.

Hans,

You live in Norway?

I think you should check what the local regulations or customs are and involve a local expert.

I have my doubts about the feasibility, without extreme measures (and even then). This then must all happen in a limited space and height.

Andrew,

It's difficult to compare a coupled structure with an in- outside situation.
In the latter you have no flanking. The intensinty outside by definition is lower (free field propagation) than inside.
This last point means that exactly the same wall, while ignoring any flanking, and the same emission level, still will result in lower outside pressures in the in/out situation than in an in/in situation. (theoretical difference between 3 to 6 dB depending on room acoustics).
Also night levels inside a home or appartment are often much lower than outside (added insulation home versus outside noise in the absence of internal sources).
What you hear depends on the masking by the background noise (dynamic exceedance range).

Basis:
1) What levels do you play?
2) Which type of music (function of bass content)?
3) What's the current insulation?
4) Are there regulations or local customs to be taken into acount?
5) What are the max target immission levels (receiving site), in function of 4) and/or environmental disturbance?
Be careful not to make your studio dependent of the goodwill of the neighbors!!!!

Take note that standards, regulations and laws can be different for professional/commercial and private use.
Even when non-professional, a judge will use professional standards levels to judge disturbance, with possible complaints when you use the studio a lot.

Mostly it's cheaper (or only solution) to search a location elswhere, but depend of course on local circumstances.

Best regards
Eric

hansp wrote:
Andrew; your design looks interesting, might be just what I' looking for!
From what I understand, you don't have any floating floor under the the walls, is this right?
Love to get some drawings/plans of your design.

HP.

It's not my design - just what I learned from this forum

There is no floating floor. Both the external wall and the inside wall rest on the same concrete slab.

10 ft from the building you can't really hear anything - while drums are being played as loud as possible. 30 feet on my porch - absolutely cannot hear a thing. I'm confident when it's all done we'll be able to play a full band at 3am in the morning and have no problems. Just done tests so far with drums and guitars because the place is not finished - the control room isn't built yet and none of the painting etc is done. With loud guitars the sound control is even much better than the drums - you can't hear them at all stood next to the wall outside.

I did another test with a hifi on full blast - this is obviously lacking in the bass, even with your head pushed up against the outside wall you can't hear anything at all.

It should get even tighter when the control room is constructed because that will effectively offer even more soundproofing to the live room. Also the drums will be on a concrete pad - this isn't poured yet so the test was just drums on the main concrete floor.

Well, guess I should have said "the design you are using" and not "your design", sorry.

My carpenter and I agreed that we both will seek advise from professionals, he will ask his acoustic consultant and I will ask you guys, and I just hope we can get a good solution.

The way my rehearsal space is now, it can only be used after office hours and until 10 pm. It's not a requrement to be able to play a band at night in the new studio, but it certainly is a plus, and a goal to strive for when buiding it. I'm a believer in doing things right the first time even if it will cost a little more time, patience and money etc. That will always pay off in the long run.

What I'm most concerned about at the moment (reg. my design) is the walls between cr and live room facing the north buildig. The wall between the studio building and the north one is the weakest of them all, and in the way I've drawn it, the gap of air between my rooms looks like it will escape into the next building.

The only solutions I can think of at the moment is to either build the outer wall of the studio completely by itself before the rest of the studio and only have single wall on the floating floor.

Or sealing the live room walls together with the cr walls at that point.

One other solution is to build to whole studio on one floating floor with the same outer walls, and just add the cr walls inside this, but I guess this is not good.

Han, one way to save a bit if you're floating floors mainly for isolation from the outside world - only float the LOUDEST room. If, for example, you're using the live room for tracking drums (or rehearsing with full band) then that should be the room with the floated floor.

If you're monitoring mics for best placement, you will still get good isolation from the live sound by floating the live room floor.

Keep in mind that floating floors need to be planned with full knowledge of the load that will be placed on them, so proper deflection of the isolating materials can be achieved. Beyond that, the only good you will see by floating everything on the same floor will be isolation to the outside. For best isolation between rooms, the floors need to be isolated from each other, same as walls and ceilings.

When you say North, is your drawing oriented with North at top like a map? And, can you clarify the construction as it is presently?\

Eric makes some very good points, BTW - there are times when it's better to just walk away from a site.

Your answers about present construction (as much detail as possible) will help figure out the best way to go... Steve

With north I indeed mean like a map, so nort=top of drawing.

Moving to another space is not an option for me, since I live two floors up in the building and are planning to stay there for a long long time

The building as it is now:

No walls other than the toilet and the room next to the toilet.
The floor is concrete with linoleum/vinyl on it.
I belive the left and right walls are concrete, perhaps with leca blocks.
Top wall is an old stone wall with a bit too much sound leakage.
Bottom wall is as far I know single or dual layer gypsum. The room that is already there will be used as an archive-room and has single layer gypsum with steel studs.
The ceiling is concrete with two floors of wood construction on top. I think the ceiling concrete is about 20 cm thick, and the two upper floors rest on 2x6 type studs on the concrete.

Room height is 255 cm.

Construction will start in one or two weeks, so it would be great if we can reach a conclusion within the end of this week.

How much difference in stc will there be from floating the floor as opposed to not floating it? And the same with the ceiling; difference in lowering existing ceiling as opposed to float the ceiling on the new walls?

And how about my question in my last post regarding leakage of sound between walls?

Thanks,
HansP.

Hans, sorry for the delay - work has been less than fun lately, still that way...

I'm starting to agree with Eric on the feasibility of your room being usable on a 24/7 basis - you might be able to get there, but not without more time and thought as to construction/soundproofing.

Even though I thought I'd stated these basic concepts in the thread I linked to, I'll see if I can put it a bit more concise here -

Turning wall studs flat does nothing but waste materials - Here is a list of things that work/don't work, and why -

Best soundproofing is achieved in ANY direction when the sound must travel through two leaves of mass separated by one air space. The air space can (and should) have fiberglas or rockwool insulation in it, optimum for sound control is around 2.5 PCF, or 45 kG/m^3.

Higher mass in the leaves gives better isolation. Having one leaf with a DIFFERENT mass than the other improves isolation. After a certain point, much more mass is required to notice much of a difference.

A wider air gap between the two mass leaves improves isolation. Increasing this gap beyond about 8" or 200 mm has less and less results.

Both leaves of mass need to be hermetically sealed, regardless if you will then break this seal with HVAC - that part must be done carefully and with no short runs, several bends, duct liner for silencing air flow, proper gratings, etc - do NOT put electrical outlets back to back in the same stud cavity, and DO thoroughly caulk all penetrations. The less penetrations, the better - NONE is just the right amount. Consider surface mount electrics because of this.

When mounting multiple layers of gypsum wallboard on frames, do NOT glue successive layers of wallboard to each other - use fewer than normal screws for the first layer, allowing the longer screws for successive layers to help hold the first layer. The fewer screws, the less flanking through the fasteners.

When trying to minimise flanking, as you need to do, then some type of floating floor, along with resiliently mounted inner wallboard leaves, plus resiliently suspended ceiling inner leaf, will all be necessary. Your already low ceiling will make this difficult at best. Remember, increasing the air gap between inner and outer leaves helps isolation.

Your old stone wall will need to be "rendered" , or coated with at least 12-15 mm of mortar, in order to seal it. Not doing so will cost you somewhere around 10 dB isolation. Once that's done and dry, you should paint it with a heavy bodied paint for a few more dB isolation, then you can move inward about 150 mm and put up a stud frame with at least two layers of 15mm gypsum - a third 12mm layer between those two wouldn't hurt. IF you use lightweight 25 gauge steel studs, you won't need to use separate resilient bars/channels - all the gypsum would be placed on the same side of the frame, first putting insulation batts between the frame studs.

Your floor should be floated, at the very least in the live room where drums/bass will be tracked. In the CR, you should normally only be monitoring at around 85-90 dB SPL so would not need as much inside-to-outside isolation as live drums at around 110 dB.

Your goal, as I said, is to have two centers of mass between any two areas to be isolated - in order to minimise flanking into your concrete walls and therefore to the rest of the building, you need your inner mass leaves to be resiliently attached in some way so that they don't couple as much sound into structure. Same with floor and ceiling.

Your already low ceilings will make all this a compromise, but if you can live with a total loss of height of around 25 cm, I think you can get very close to the results you're after.

Once the place is isolated, acoustics will be difficult as well - the stiff walls necessary for isolation are NOT what the doctor ordered for best sound quality... Steve

I updated my drawing a little to include a wall between the stone wall and the studio walls. Because of a concrete stud, the wall has to be about 50cm from the stone wall.

Lowering the floor from 255 to 220 is alot, considering that almost all bassists I know are about 200 cm. Is the floating floor included in this calculation? Hope so, but afraid it isn't.

I've just aquired two windows of about 200x60 cm size, and since this is a little longer than planned, I was wondering if it is possible to have these inside the wall for a couple of cm to make soffit mounting possible.

What about retrofitting a floating floor in the control room? Is there any point in doing this or will it just be waste of money?

How much impact will it make if a layer of drywall is added on the inside walls and ceilings at at later point?

HansP.

You can do a floated floor on existing concrete in about 14 cm, a drop ceiling depends on whether you can use hangers from existing ceiling, or if it's not strong enough then ceiling joists resting on inner wall frames would be necessary.

If you need to support ceiling joists on your inner wall frames, 2x6" joists will span 13 feet using #2 and better douglas fir on 16" centers (that's 35mm x 140 mm joists, and a span of 4 metres) - if you increase joist size to 2x8, still on 400mm centers, you can span up to 16'6", or 5 metres. Both of these ratings will allow up to three layers of wallboard maximum to be mounted on resilient channel under the joists.

So, if your spans are under 4 metres, you would lose about 14 cm on bottom and about 18 cm on top, for a total reduction of about 32-34 cm in headroom.

I'm not sure how you would overlap a window or why it would help - can you do an example drawing?

Retrofitting a floating floor can work OK, but you need to look at the overall picture to know if it will be pointless. If there are other, weaker parts of the room (isolation-wise) then a floated floor won't help. If the floor is the only place where sound can flank to other areas easily, then floating it properly could help quite a bit. It also depends on how much isolation you need, and from what...

Adding extra layers of wallboard can help or hurt - if you're mounting on Resilient channel, extra weight can cause failure. On walls, it may only result in worse isolation due to overloading of the resilient channel. On a ceiling, it can result in injury or worse. If the wallboard is mounted directly on a double frame wall, the extra fasteners will reduce some of the improvement because of flaking through the fasteners, but there would still be a net gain. This gain is less for each additional layer, because it's a percentage thing - going from one layer to two doubles your mass - going from two layers to three only increases mass by 50%, etc - each 5-6 dB of improvement requires a doubling of mass.

Hope that helps... Steve