John Sayers' Recording Studio Design Forum Archive

I have been asked to spearhead the building of a recording studio on our church conference center grounds in Salem, Oregon, USA. I have received “valuable” experience building a lousy home studio before and am determined to give this new opportunity my best effort for obtaining the best results based on REAL knowledge. I’ve been periodically lurking in the forum for years and it’s a dream to me to be trusted by my friends to put together something that would really WORK! My job is to design and spearhead the studio project and keep the zealous builders & handymen from rushing in and doing all the wrong things.

I have a building that is set apart from other buildings in the back of our 32-acre conference center. The interior sheeting and insulation on the walls and ceiling have been recently gutted and all windows and doors (but one) are filled in and exterior siding replaced. Walls are 2x4 timber studs spaced 16” apart. Trusses are 24” apart and built of 2x4 timber. It has a concrete slab floor (good news). Existing exterior walls are of ½” plywood, Tyvek and siding. The single door is near one corner and the electric panel is in the opposite corner and will most likely be replaced and possibly moved (unclear how to deal with that).

I have read through Rod Gervais’ book Home Recording Studio and plan to follow it as strictly as possible (What a great resource! – wish I had found this a long time ago!). Current plans are to start adding mass to the exterior walls by adding drywall in-between studs from the inside, along with backer rod and acoustic seal – a painstaking process. This will lead me to the first two questions I would like to ask at the end of this post.

Interior dimensions: 23’ 5” by 23’ 6” from wall to wall and 96” from concrete to bottom of trusses overhead (a height concern here).

Budget: We are looking at around $30K to $40K budget stretched over the remainder of the year and the next two budget years, figuring an 18-month project, based on annual budget and manpower availabilities. I need to use up this year’s budget ASAP by buying materials before losing it (if I don’t use it, I loose it).

Sound Levels:
Our music will consist of the following categories:
• Adding vocals to pre-recorded instrumentals (easy!)
• church youth choir of up to 20 singers;
• orchestra string ensemble (up to 20)
• Jazz band (horns, guitar, bass, drums (acoustic or electric), vocals)
Outgoing sounds (“A” weighting, slow response from Radio Shack 33-2050):
• I measured the electric bass and acoustic drums 96dB inside, 66dB outside building at 3 feet, 51dB at the nearest guest cabin 35 feet away.
Incoming sounds:
• Worst case - our loudest groundskeeping lawn mower is 98.5dB outside of building, and currently 85dB inside (untreated walls). I think this is a bit too much to think we can eliminate. I am guessing we will have to schedule around mowing??
• Occasional car on asphalt passing by at 5mph about 15’ away (once/hour max during events).
• Guests outside talking/shouting, children playing etc. during events.

I have two pressing concerns that I want to ask about:
1. Can someone help me decide how many layers of 5/8” drywall for my walls are appropriate? As a starting point, I was thinking 2 layers inside the exterior wall (between studs) to add exterior mass and 2 layers on inside of 2nd inner walls. The order from outside to inside is: original siding, plywood, original studs with 2x 5/8” drywall (sealed), with insulation batts then new 2x4 inner walls, insulated, with 2 layers of 5/8” drywall. If this many layers is overkill, I’m wasting my budget. If under-kill, I’m wasting money on something that won’t work. I need to use what’s left of this year’s budget NOW to order the drywall while I still have the money available.

2. I haven’t figured out the best way to have an isolated ceiling. The concern here is height (only 8 feet from concrete floor to bottom of trusses). I came up with an idea of adding drywall to the inside of the roof between trusses (like my exterior walls) for the external mass and then use RC or RISC to hang the interior drywall layer(s) from the trusses (insulation between trusses). This will not take up much of my precious height. Can I get help with this so I can sleep better? 

I am attaching a 3D Sketchup draft layout of the studio, another with 2D floor layout with dimensions and a current pic of the gutted room.

"1. Can someone help me decide how many layers of 5/8” drywall for my walls are appropriate?"

To achieve the highest degree of isolation, upwards of STC 69 in an ideal assembly, you should use 2 layers of 5/8 fire rated type gypsum. But this mass has to be maintained on both sides of the framing assemblies. So the exterior walls would be massed as you suggested, I do not think you need backer rod, but you will use a tremendous amount of caulk thru the entire process.

I like what you mention about massing up the roof, but let me ask you this. How is the roof vented for air? I would almost think it has gable end vents and soffit vents. I would consider eliminating the gable end vents, side it up. Then install a continuous ridge vent. This will remove the penetrations that sound will creep into but allow the roof to properly vent.

Have you thought of massing up the top side of the joists, kind of like an inside out ceiling?

Hi there "Guit-picker", and welcome!

My job is to design and spearhead the studio project and keep the zealous builders & handymen from rushing in and doing all the wrong things.

I wish you good luck with BOTH of those, but from many years of experience in church building projects I can pretty much assure you that the second part will be much harder than the first part... The enthusiasm of many well-meaning church volunteers unfortunately exceeds their skill level by a few orders of magnitude. That's not to say that it's not a good thing! It certainly is excellent to have enthusiastic handymen on board to turn the design into reality, and indeed it's a blessing... but channeling that enthusiasm into careful studio construction isn't so easy... especially if you have experienced tradesmen on the team: Since they are the guys that supposedly already "know how to build", everyone else (even the pastor and other church leaders) tend to look to them and trust them in the construction process, without realizing that that's a big mistake: building a studio is not the same as building a house, office, shop, school or church. There are very many differences, so tradesmen cannot just go ahead and do it "the same way we always do it", because the "same way" is invariably "the wrong way" for a studio.

I'm starting out with this long explanation because I live it all the time in churches, both in my own and in the many that I do consulting for. It's often hard to get it across that normal construction methods are not suitable for sound isolation structures, because most people simply do not understand sound. For example, sealing: pastors, contractors, and the congregation in general will not understand just how critical it is to seal EVERYTHING air-tight, so there will be major discussions about the huge amount of caulk that you'll be buying: very few will understand that it is ever bit as necessary as the studs and the drywall; without the caulk, you don't have an isolated studio just as much as you don't have one without the studs and drywall. Trying to get that across isn't easy. Ditto with holes in walls: nobody will "get" why you can't just chop a hole in any old place to put in switch, outlet, light or other fixture: after all, "That's the way we always do it, and it always worked before!". Your explanations will fall on partially deaf ears, unless you take the time to first train the entire build team in the huge importance of maintaining the integrity and the seal of the isolation leaves.

It will take you a concerted effort to teach the build team and the leaders how to do this right, if you want it to be successful. That is likely to be your biggest headache, right up there with getting budget approval...

Anyway, on to your questions:

The interior sheeting and insulation on the walls and ceiling have been recently gutted and all windows and doors (but one) are filled in and exterior siding replaced. Walls are 2x4 timber studs spaced 16” apart. Trusses are 24” apart and built of 2x4 timber. It has a concrete slab floor (good news).

So far, so good! You have a great base for the build. Just checking: Did you seal that outer leaf very, very carefully, with abundant oceans of caulk? If not, then now is the time to do that, while you still can. It will give your build team something to keep them busy for a while, and will be good practice for them to get used to sealing everything. The rule is: "If it looks like a crack or gap, then seal it. If you aren't sure then seal it. And if you are certain that is NOT a gap or crack, then seal it anyway, just in case."

The single door is near one corner and the electric panel is in the opposite corner and will most likely be replaced and possibly moved (unclear how to deal with that).

Yep. At some point fairly soon you'll need to move that panel close to the entry door. The exact position will depend on the overall design.

Current plans are to start adding mass to the exterior walls by adding drywall in-between studs from the inside, along with backer rod and acoustic seal – a painstaking process.

Yep!

Budget: We are looking at around $30K to $40K budget

That's probably in the ball-park, provided that you work carefully, and that your labor is mostly volunteer, and therefore zero cost!

Outgoing sounds (“A” weighting, slow response from Radio Shack 33-2050):
• I measured the electric bass and acoustic drums 96dB inside,

There's the first problem: You should have measured that with "C" weighting, not "A". "A" is insensitive to low frequency sounds, and also to very high frequency sounds. "C" is a better match for the way human ears perceive loud sounds, so you should measure that again using "C". Yes, I know that your local noise regulations most likely specific your LEGAL levels as "A" weighting, since that's the way low-level ambient sound is measured, but "C" is the correct way to measure high-level music, and is the way isolation is measured.

• I measured the electric bass and acoustic drums 96dB inside, 66dB outside building at 3 feet, 51dB at the nearest guest cabin 35 feet away.

When you re-measure, you'll find that your real level inside for bass and drums is more like 115 dBC, which will be more like 80 just outside the building, and more like 60-something at the guest cabin. Those are all loud, whichever way you look at it.

• Worst case - our loudest groundskeeping lawn mower is 98.5dB outside of building, and currently 85dB inside (untreated walls). I think this is a bit too much to think we can eliminate. I am guessing we will have to schedule around mowing??

Not a problem. It is perfectly possible to get a 100 dB lawnmower outside down to 40 dB inside, or even less if you design and build it right. The spectrum of the lawnmower engine will likely be in the range that can be controlled quite well with your isolation walls, and certainly controlled better than our out-going drums and bass!

• Occasional car on asphalt passing by at 5mph about 15’ away (once/hour max during events).
• Guests outside talking/shouting, children playing etc. during events.

Those should also not be too much of an issue, if you design and build the isolation system suitably.

1. Can someone help me decide how many layers of 5/8” drywall for my walls are appropriate?

It's not just the number of layers that you need to work out, but also the size of the air gap between the two leaves. The wall is a tuned system, that has to be tuned to at least an octave lower than the lowest frequency that you need to isolate. You tune it with both mass and air gap.

That said, at a very rough guess (I didn't do the math! Just "guesstimating"...) with 2 layers of 5/8" drywall on each leaf and an 8" air gap, filled with insulation, you should be able to get the type of isolation that would allow you to track a loud 20-piece Gospel Rock band session late at night, or alternatively track a single delicate worship vocal with the lawnmower going nuts outside the door.

However! (And this is a big "however")... That "guesstimate" assumes that you design not only the walls to get that isolation, but also the ceiling, windows, doors, HVAC system and electrical system to get the same level of isolation. It can be done, but you are pushing towards the limits of what can be accomplished for isolation using only studs and drywall, so this will need careful attention to detail...

The order from outside to inside is: original siding, plywood, original studs with 2x 5/8” drywall (sealed), with insulation batts then new 2x4 inner walls, insulated, with 2 layers of 5/8” drywall.

Correct, provided that you leave that 8" air gap between the outer-leaf and the inner-leaf.

If this many layers is overkill, I’m wasting my budget. If under-kill, I’m wasting money on something that won’t work.

Rest easy: It's not overkill, and it will work.

2. I haven’t figured out the best way to have an isolated ceiling.

Join the club! This is usually the toughest part of most builds, and the part that will give you the most headaches in both design and construction.

I came up with an idea of adding drywall to the inside of the roof between trusses (like my exterior walls) for the external mass

You could do that, but I would use OSB or plywood for that, not drywall. The roof deck is exposed to extreme temperature changes, and humidity, and other issues that drywall isn't much good for. So if you want to go this route, then you could "beef up the mass" with OSB IF IT IS DONE CORRECTLY! For example, assuming you have asphalt shingles on top, you should find that the roofing nails are protruding through the deck just a bit, and you cannot mess with that! They are supposed to protrude. So you can't just press up bits of OSB against those nails, as you'd be pushing them back through. You'd need to press a sheet of some type of closed foam in there, covering the nails without moving them, then put your OSB on that.

However: This is not a good plan, for many reasons. I'd suggest that you seriously consider re-doing your trusses, once again for several reasons. If you do them as scissor, raised-tie, raised-tie-scissor, or parallel-chord trusses, then you can firstly gain a lot of extra ceiling height for your rooms (which is very useful, acoustically!), and also provide a better solution for your isolation.

At first glance this sounds hugely complicated and you probably discarded the idea before even hearing me out (!), but it's not such a big deal as it sounds. I did this for a studio for one of my clients in LA last year, and it worked out fine.

Just to clarify; You do not need to take off your roof to do this! The basic concept is that you build the new truss system inside the existing roof, then you take out the old one after you are finished. You start by putting a couple of hefty wood columns at each end of the building, and inserting a new ridge beam just below the existing ridge beam, to take the weight of the entire roof. Then you build your new trusses (I did raised tie scissor for that studio in LA, but ordinary scissor would be nearly as good), one at a time, then finish up by taking out the old truss members, which you can then save and re-use for building your walls (reduce expenses).

If you'd like to look into this, I can send you some details by PM of how we did that, so you can see for yourself. I'll also put you in touch with the client, if you have any doubts. I can't post anything on-line, as I don't have clearance from that client to show his studio details in public.

The concern here is height (only 8 feet from concrete floor to bottom of trusses).

You could probably get that up to 10 or more feet for the central span, if you do the new trusses. That would give you plenty of room to do your ceiling isolation to the same level as the wall isolation, plus it gives you room for your HVAC system, and also allows you to have a significantly higher final ceiling in your live room at least, and perhaps also in your CR, if you want.

then use RC or RISC to hang the interior drywall layer(s) from the trusses

You would be greatly limiting your ability to isolate the studio like that, since your inner-leaf ceiling would be attached directly to the outer-leaf trusses, with only the RC for isolation. RC (or RSIC clips) helps with isolation for some circumstances, yes, but in your case you need more isolation than it can produce. If you go with RC (or RSIC clips) then you might as well use only one layer of 5/8 on your wall leaves, since you'd be wasting money otherwise. If you have great walls but a mediocre ceiling, then there's no point spending all that money to make the walls great! You'd also have to live with a lower level of isolation for the entire studio, likely in the region of the high 40's to low 50's. So no more late-night jamming sessions for the praise & worship team, and no more tracking with the lawnmower outside. You limit your options like that.

Can I get help with this so I can sleep better?

What I would suggest is the same as the studio I did in LA: To avoid great expense and complications in "beefing up" the roof deck and making it into a sealed system with no ventilation in the attic space (complicated...), we just left the roof deck exactly as it was, ventilated correctly, but we switched to the raised tie scissor trusses, then sheathed that with plywood and drywall, to create a new "outer" leaf, independent of the roof. In reality, that new leaf is technically the "middle" leaf, since I designed this as a three-leaf roof ( gasp! ). Yup: sometimes you have to do that. As long as you compensate for the losses, it can be done. So after that was done, the final "outer" shell of the studio was the walls plus the new "middle" leaf ceiling, which had a large flat section across the middle of the building at 10 feet above the floor, and angled sections on the sides, going down to the walls. We then built the inner-leaf rooms inside that shell, and also used some of the extra headroom for the HVAC system, to avoid losing floor area for that.

I'd suggest that you should do the same. PM me if you want more details.

I am attaching a 3D Sketchup draft layout of the studio,

That's probably not the best layout, considering your needs that you mentioned up front. The corner-style control room might not be the best use of space for your situation,k and the angles are not optimal anyway.

Also, the inner-leaf walls of the rooms are not done correctly! The walls of the live room are directly tied to the walls of the iso booth and the sound lock, but that cannot be allowed to happen. Each room must be built as an independent stand-alone single-leaf room with it's own independent ceiling.

Next, although it's great to use sliding glass doors between rooms, you probably don't have the budget for that. Each acoustic-rated sliding glass door is going to cost you around US$ 2k to US$ 3k, so you'd be blowing a third of your budget on doors alone. Considering that HVAC is going to take up another third, that leaves you with precious little to build the actual rooms. I'd suggest rethinking your door concepts along the lines of site-built doors, similar to what Rod shows in his book. They will work out a lot cheaper than four large acoustic-rated sliding glass units. You can put glass in them if you want more light, better sight lines, etc.

Finally, the layout with the CR is not good at all, acoustically: You have the speakers on the desk (a big no-no!), the desk is too far back into the room, the speakers are too far away from the front wall (more on that later), and the mix position is roughly in the worst possible location: the geometric center of the room.

Yes, there's this "rule" that speakers should be far away form the walls, but most of the people who parrot that "rule" don't understand why, or how, or where, or which, or what! They just repeat it, because they read it somewhere, so they think it must be the eleventh commandment... Of course, it isn't. In fact, it isn't even a rule at all! It's a guideline, which should be preceded with the qualifier: "If your room is big enough, then...". In other words, the rule should go like this: "If your room is big enough that you can get your speakers at least six feet away from all walls, while still having them at acoustically acceptable locations in the room, and covering all of the listening positions correctly, then do that, but make sure they are not the same distance away from the front wall and the side walls, nor the same distance from the floor or ceiling. None of those dimensions should be the same, or even close". The second part of the rule should go: "If your room is not big enough to do this, then your speakers should go tight up against the front wall, with only a 4" panel of porous absorption between the speaker and the front wall." The reasons for the above are a bit complex to go into, and I'm running out of time to answer your post anyway, but if you want to learn about why this is, then search for things like SBIR, LBIR, phase cancellation, comb filtering, power imbalance, diffraction, and suchlike.

That said, if you REALLY want your studio to be as good as it possibly can, then just soffit-mount your speakers: if you do that, all of the above technical scary monsters just disappear: they stop being an issue, because they are all related to the way the speaker acts inside a room, but if you soffit mount your speakers, then technically they are no longer inside the room! So none of those ugly artifacts can even occur...

Anyway, I hope I've gotten you on the path a bit better, and I'm really looking forward to following your thread, as you are going about this the exact right way, with plenty of time, a reasonable budget, and a reasonable basic knowledge of what you can achieve realistically, and how to get there.


- Stuart -


EDIT: Oooops!! I didn't notice that Brien was replying at the same time I was! But fortunately we are both saying roughly the same thing.... He just says it in fewer words than I do.... I do tend to waffle on and on, sometimes... unnecessarily ....

Wow! Thanks Brien and Stuart for all your input. I made the mistake of reading your replies just before going to bed late. The ol’ brain wouldn't shut off until about 3am!

You guys gave me so much to consider that my head is swimming!.... but very good input and I appreciate it. I think it’s too much to respond to everything in one sitting, but I’ll start with the most expedient things first - dictated by the need to order supplies that I can order NOW in this calendar year – mainly supplies for the outer leaf mass. Yesterday I just picked up and delivered 48 sheets of 5/8” drywall for the outer two layers.

I do not think you need backer rod, but you will use a tremendous amount of caulk thru the entire process.

Brien, I understood from the book and on the forum that for EACH layer it is best to use backer rod and seal. Isn’t the purpose of backer rod to allow me to conserve on acoustic seal? I bought a 20’ package of it for test. In package form (20 feet), it costs 16 cents per linear foot. Maybe I can order it in bulk.
I was figuring on the standard ¼” gap around each piece of drywall with backer rod and acoustic seal over that. Same with 2nd layer. I tallied up ALL the nooks and crannies between studs and it totals 1433 feet for the first layer on the exterior walls. I’m in a quandary to guess linear feet to expect per 28 oz tube in order to estimate quantities. I can order OSI SC-175 (that I’ve seen mentioned on the forum) only by the case of 12(ea) 28 oz. (about $77) but how many linear feet per tube is a reasonable estimate using backer rod and without backer rod? Also, is this SC-175 the right stuff to use? How is it to work with?

I would consider eliminating the gable end vents, side it up. Then install a continuous ridge vent.

Great idea! I will put that in the plan!

Have you thought of massing up the top side of the joists, kind of like an inside out ceiling?

Yes, sort of a “drywall attic floor” if you will. That was my first idea, then it looked like a major problem getting full sheets of drywall up there, in-between the trusses, but I found a couple ways to do that since. I like this idea best, but the worry is having a low ceiling in the end! This brings me to all the ideas that Stuart put out.

Stuart, I want to respond to a bunch of ideas you started, but have to leave now for a function. Thanks for the advice about dealing with construction workers and the sort. I have some pretty-good experienced workers and so far, they are responding well to my “crazy ways” of building a sound studio. I think it will work out well if I stay on top of it.

Can’t wait to continue the dialogue as soon as time permits. In the mean time, I will respond to one easy one:

There's the first problem: You should have measured that with "C" weighting, not "A".

The good news is: Being that I’m an electronics tech, I am accustomed to measuring the heck out of things and I measured both “A” and “C” weighting, both fast and slow on each, so I measured four ways. I was so tired when I posted that I erroneously put up the wrong data set, knowing that “C” is recommended. Also, I lost the actual linear distances measured and was resorting to estimates in order to get my post started and have since re-measured. The updated info (for what it’s worth) is as follows:

Sound Levels:
Outgoing sounds (“C” weighting, slow response):
• I measured the electric bass and acoustic drums 99dB inside the room
• 78dB outside building at 3 feet
• 69dB at the nearest guest cabin 74 feet away
• 64dB at nearest camper 111 feet away
• 58dB at property line 263 feet away.

Incoming sounds:
• Worst case - our loudest groundskeeping lawn mower is 104dB outside of building, and currently 85dB inside (untreated walls).
• Occasional car on asphalt passing by at 5mph about 24 feet away (once/hour max during events).

Got to run, but I want to say that I’m so grateful for your advice on this matter, feeling excited and a bit scared at the same time, taking on this awesome project. Looking forward to further dialogue (and I will try hard to search the forum for things already answered).
Best regards,
Ron Smith (Guit-picker)

(“C” weighting, slow response):
• I measured the electric bass and acoustic drums 99dB inside the room

Are you SURE about that? I don't know many drummers that can play that quietly! Was that some type of soft jazz number he was playing, played with wire brushes? 99 dB for drums is looooow. Mostly I measure drummers at around 110 to 115, and they can do even better if they try hard...

I'm just a bit surprised that you got such a low reading there. It's also really hard to figure out how drums could measure only 2dB louder on "C" than on "A"!

Yesterday I just picked up and delivered 48 sheets of 5/8” drywall for the outer two layers.

If you still have money left in your budget that you need to spend, stock up on as much 4" OC-703 as you can, and several cases of acoustic caulk. You'll need all of that, and more. And if you really want to go for maximum isolation (and can increase the budget a little) then also order a few cases of Green Glue compound.

Got to run, but I want to say that I’m so grateful for your advice on this matter

That's what we're here for!


- Stuart -

"Brien, I understood from the book and on the forum that for EACH layer it is best to use backer rod and seal. Isn’t the purpose of backer rod to allow me to conserve on acoustic seal? "

The reason for backer rod is to fill a void. My experience is that I can cut pieces into the stud bay and use a sheetrock rasp to flatten the edges, install and caulk. This is in no means an attempt to usurp Rod. He knows what he knows but he also knows that not everyone does this type of thing.

So, when I do it, I cut the sheetrock to fit the bay, caulk then add another layer as required, install caulk and insert cleats.

The backer rod assumes a large void which has to be filled with something. Backer rod and acoustic caulk fit that bill. But the less void you have you reduce the need for added backer rod cost and simply install acoustic caulk.

It will not reduce your isolation only your man hour time.

Sorry it took so long to get back - DON'T GIVE UP ON ME!!! I've been buried with other events and been thinking about all your input every day, wishing I could get back onto the forum.
Thanks Brien for clarifying about backer rod and caulk! I'll use your method!

Stuart:

"If your room is not big enough to do this, then your speakers should go tight up against the front wall...

if you REALLY want your studio to be as good as it possibly can, then just soffit-mount your speakers

I really like your input here! I wanted soffit-mounted speakers in the first place, but got the impression that Farfield speakers are really spendy and I couldn't find a lot of info on the idea and I see most of the examples of studios are using nearfield setups. Here's the situation: I purchased Yamaha HS8 powered monitors. They are rear ported!!! I think that would be a big problem with either soffit-mounted or against the wall, don't you think? I'm already wondering if I should either sell them and buy something front-ported or even offer to swap with my personal Roland DS90 set in order to mount them better and avoid all the aforementioned headaches. You are making perfect sense here!

Also, the inner-leaf walls of the rooms are not done correctly! The walls of the live room are directly tied to the walls of the iso booth and the sound lock, but that cannot be allowed to happen. Each room must be built as an independent stand-alone single-leaf room with it's own independent ceiling.

OK, time for true confession: (You're going to tear this apart!) I purposely put a lower expectation on isolation between the larger sound room and the two vocal booths. The attempt here is to try for a versatile setup so I can open up the vocal booths and convert it into a single larger recording room (i.e. swinging walls like large doors - notice the arcs drawn on the floor?). This would allow me to get a small orchestra or youth choir in the room when opening the walls. Other times, we could close them up for vocal isolation. I know this compromises the isolation between the large room and the vocal booths, but I'm trying to hang on to the larger room size and still have some sort of vocal booths when needed. I was figuring on two ceilings - one for the CR and the 2nd for the rest. I have a metal fabricator in a shop next door that could build the steel swinging frame for me (think giant version of gate frames you can buy at Home Depot). I expect that most of the use of the isolation booths will be for vocals and not much else - perhaps an acoustic guitar? So, go ahead.... tear into my idea.... I can take it!

Still digesting the truss-replacement idea. Thanks, you guys!
-Ron

but got the impression that Farfield speakers are really spendy and I couldn't find a lot of info on the idea and I see most of the examples of studios are using nearfield setups.

Actually, all those names such as "farfield" and "nearfield" are just marketing hype! In reality, there's no such thing as a nearfield speaker or a farfield speaker, since the terms "near field" and "far field" actually refer to the room, not the speakers. If you sit closer than the room's critical distance to a "farfield" speaker, then you are, by definition, in the room's "near field", regardless of the wording on the box that the speaker came in. And if you are sitting further away form the speaker than the critical distance of the room, then you are, by definition, in the "far field", despite what the words on the box might say.

If you ask five different speaker manufacturers for their definition of "near field" you'll get at least five different answers, and they'll be in conflict with each other. Some say it is a specific listening distance, others say it is all about where you place the speaker, others talk about angles and suchlike... But do a google search for "definition of nearfield speaker" and see what that turns up....

OK, in other words: use whatever speaker you want! As long as you are seated far enough away from the thing that the fields from the various drivers are well merged, then you are fine. For most speakers, that distance isn't too large.

The only real restriction on soffit-mounting, is if the speaker is rear-ported or side-ported. Those are really hard to do. So choose a speaker that is either front ported, or not ported at all. Personally, I'm partial to the Adam A7X and A8X, as well as some of their bigger offerings. Genelecs are pretty good too. So are K&H, and some of the Focus models. And many others too.

I purchased Yamaha HS8 powered monitors. They are rear ported!!! I think that would be a big problem with either soffit-mounted or against the wall, don't you think?

Rear-ported speakers can be soffit mounted, but it isn't as easy as for front ported or un-ported.

The attempt here is to try for a versatile setup so I can open up the vocal booths and convert it into a single larger recording room (i.e. swinging walls like large doors - notice the arcs drawn on the floor?).

Those would be hugely heavy... And very hard to seal when they are closed. You won't be able to get good isolation like that, but it seems that isn't something you need?

I know this compromises the isolation between the large room and the vocal booths, but I'm trying to hang on to the larger room size and still have some sort of vocal booths when needed.

Eat the cake, and also have it? I seem to remember a saying about that...

I have a metal fabricator in a shop next door that could build the steel swinging frame for me (think giant version of gate frames you can buy at Home Depot).

If you do go that route, then put castors under it. There's no way you could hang that on a hinge, successfully. Or rather, not at a reasonable cost.

So, go ahead.... tear into my idea.... I can take it!

Rip! Rip!

What you are proposing can perhaps be done, but I wouldn't hold out for isolation much beyond about 30-something dB. Is that enough? That's what a typical house wall gets...


- Stuart -

Thanks for your good information Stuart! Your explanation of farfield vs nearfield is just what I wanted to hear (no pun intended)! I think I'll end up buying a new set of speakers for the studio.

Yes, the swinging wall idea will be very heavy and I also figured that castors will be in order. The "hinge" would be a set of pipes from ceiling to floor with an inner and outer "sleeve". It would be an engineering feat, and I have access to a couple of mechanical engineers to help with it. I agree, it will be a compromise on the isolation between vocal booth and main recording room. I was going to use automotive weatherstrip as described in Gervais' book. It's all just theory at this point, but I'm intrigued.

We are preparing drawings of trusses to present to a structural engineer for a stamp. I was so relieved that the decision makers over my head didn't blink an eye over this idea!!! In the meantime, we are about 80% around the room with the 1st of two layers of drywall and I'm about to order a case of OSI SC-175 to get my "helpers" started with the sealing process. I'm pretty excited to see our plan FINALLY in motion!!!

Sorry I took so long to respond. I've been running in circles. I guess I better get used to it.... it's going to be this way for quite a while
Thanks again for all your input!
-Ron

I don't want to comment on the design for your hugely massive swing doors until I see it, but let's just say "color me skeptical" in the meantime... A really deep shade of "skeptical" ...

We are preparing drawings of trusses to present to a structural engineer for a stamp. I was so relieved that the decision makers over my head didn't blink an eye over this idea!!

That's great news! In the interim, I have just finished designing a studio for another customer in the USA with a similar concept, and this is how the roof trusses ended up: (raised-tie)

Detail of sheathing:
That might give you an idea of how simple it can be. In this case, they customer gained about a foot of ceiling height in the central section, and with careful design of the rooms and HVAC, saved a lot of space.

In the meantime, we are about 80% around the room with the 1st of two layers of drywall and I'm about to order a case of OSI SC-175 to get my "helpers" started with the sealing process.

Whoa!!!! Hang on a bit there.... How did you get your SECOND layer of drywall on before you sealed the FIRST layer????? Each layer has to be sealed individually, not all of them after the fact. Sealing is the absolutely critical key part of getting good isolation, and if you skimp on that, then you just wont get where you expect to be.... The sequence should have been to first seal the existing structure in intimate detail, then put the first layer of drywall on while also sealing that at every step, then putting the second layer on and sealing that....

Sorry I took so long to respond. I've been running in circles. I guess I better get used to it.... it's going to be this way for quite a while

Yup! "running in circles" is actually the entire road map for how to build a studio...


- Stuart -

Thanks Stuart for your moral support, info and frank opinions. The swinging wall is only a concept right now. Your 30dB figure might be acceptable for our situation though. I'll give it careful consideration before committing to the idea.

I can't believe it's been a month since I've been on the forum! Been busy between the studio and keeping the rest of my world in working order! I work on the studio twice a week - Tuesday nights and Saturday half-days. They give me a couple of teenagers to help. We've got most of the first layer of drywall on the outer leaf (between studs) up and sealed and am just starting the 2nd layer. Got another case of SC-175 tonight.

Got two versions of truss drawings out for engineer approval now - one with a Glue Lam and the other without. Excited to see the ceiling rise!

Whoa!!!! Hang on a bit there.... How did you get your SECOND layer of drywall on before you sealed the FIRST layer?????

I must have skipped over your comment here before. I just noticed it. No worries, Stuart, we sealed the first layer before the 2nd. This was the SECOND case of SC-175 I ordered.

We are on hold for a while now. We have to get a permit and inspection before I can proceed any further. That will give me time to worry about other details. I will be fretting over the fresh air venting system next.

-Ron

Well, after discussions, delays, being put on hold 4 months, etc. It finally happened: I got the trusses replaced and raised the level from concrete to bottom of the trusses from 8' to 10' 5". Man, what a difference!! Nightmare #1 is over Here's a pic of the progress to compare with the photo above. Next, I need to get the electricians to give me temporary lighting, heat and plug-ins so I can continue work through the winter. I will finish the double layers of sealed drywall in a couple of undone wall spaces, then do the walls above the 8' line. I will add more vent holes in the soffets (with screens to keep out varmints) before adding drywall to the new ceiling joists.

I have questions regarding how to go about insulating the ceiling:
If I put Roxul above the drywall, it's on the wrong side for the MAM scheme. If I put Roxul BENEATH the drywall, how would I mount it (what holds it up)? I'm guessing that the right thing to do is to put fiberglass insulation above (for the R value) and plan on Roxul beneath the drywall. Then I would expect to have Roxul above the inner ceiling when it gets built. Would that be correct?

I need to use up the rest of my budget for 2015 and a big chunk of that is Roxul "Safe N Sound". I just need to do a bit of a sanity check before committing to such a large quantity of insulation to make sure I'm doing the right thing.

Also, Roxul "Safe N Sound" says it's for interior walls. I've got four EXTERIOR walls I'm planning to put this stuff in. Is it just because of the lack of R value or might it be a vapor barrier issue? Why do they say interior? Heck, I've got two sealed layers of drywall , plywood, Tyvek and siding between the insulation and the outside world.

Can you guys fill me in with some wisdom here?
Thanks,
-Ron

So you finally did it! Excellent. I'm glad I was able to influence you to do that. It will make a big difference to your studio for sure.

And it wasn't all that hard to do, now was it?

I don't know if you noticed, but this photo was taken exactly one year to the day after your original photo... and boy, whaaaat a difference!

Congratulations: Job well done!

I will add more vent holes in the soffets (with screens to keep out varmints) before adding drywall to the new ceiling joists.

Do you have a ridge vent up top? Or a gable end vent?
Either way, you will probably need to make some type of duct a foot or two long, to guide air from the soffit vents in the eaves up past the insulation that you'll need to stuff down the sides there. I have been known to use sections of PVC pipe for that (reasonably large diameter), but you can also buy other stuff to accomplish the same thing. Whatever it takes to hold back the insulation in that area, and ensure that air can flow past it freely.

I have questions regarding how to go about insulating the ceiling:
If I put Roxul above the drywall, it's on the wrong side for the MAM scheme. If I put Roxul BENEATH the drywall, how would I mount it (what holds it up)?

You need both: You need insulation both above and below your "middle-leaf". In both cases it serves acoustic purposes, but the one on top also serves a good thermal purpose, in reducing heat exposure from the roof deck down to your middle-leaf.

You can hold the "underside" layer in place with strips of plastic, wire, or mesh, stabled to the joists. You don't need 100% coverage with that; just enough to keep it in place while you build the inner-leaf under it.

I'm guessing that the right thing to do is to put fiberglass insulation above (for the R value) and plan on Roxul beneath the drywall. Then I would expect to have Roxul above the inner ceiling when it gets built. Would that be correct?

Yep. That would work.

I need to use up the rest of my budget for 2015 and a big chunk of that is Roxul "Safe N Sound". I just need to do a bit of a sanity check before committing to such a large quantity of insulation to make sure I'm doing the right thing.

If you have budget to spare, send it my way! I'll be happy to solve that extremely grave problem you have, by absorbing all your excess budget. Soaking up spilled money is something that I'm very good at! (It's a dirty job, but someone has to do it!!!!)

Seriously, if you do have budget left over then spend it on extra sealing (some cases of good quality caulk), a few cases of Green Glue, and better quality insulation: Get OC-703 if you can. That's hard to beat. The caulk and GG will come in very handy for the inner-leaf, so you might as well buy it now.

Also, Roxul "Safe N Sound" says it's for interior walls. I've got four EXTERIOR walls I'm planning to put this stuff in. Is it just because of the lack of R value or might it be a vapor barrier issue? Why do they say interior?

Good question! Better call them and ask! I can't think of any major reason why that insulation would only be usable on interior walls. So ask the manufacturer directly.


- Stuart -

Thanks a million, Stuart, for your input! ... a tremendous help!

You need both: You need insulation both above and below your "middle-leaf". In both cases it serves acoustic purposes, but the one on top also serves a good thermal purpose, in reducing heat exposure from the roof deck down to your middle-leaf.
...You can hold the "underside" layer in place with strips ...to keep it in place while you build the inner-leaf under it.

Not completely clear on that. I have been picturing putting up 23" R19 craft-back fiberglass between the new joists (6.25" - allows room for ventilation), then two layers of drywall, then (somehow) adding the first layer of Roxul. When the inner ceiling is framed later, I will add Roxul then two layers of drywall. In other words, the layers of sheetrock and Roxul will be the same order as my walls (MAM). Is that what you're describing? The unclear part is how to connect the Roxul under my smooth double layer of the outer-ceiling drywall. Not sure what you are referring to as the "middle-leaf".

Do you have a ridge vent up top? Or a gable end vent?

Yes, I've got a ridge vent on the top. Currently, in the soffets, there is a vent every four sections or so, but I believe I need venting on every section with the vaulted ceiling configuration. I have a contractor friend that I can clarify that with.

I just went to the FAQ at Roxul.com. Here's the answers to my fore-mentioned Roxul questions:
"WHAT IS THE DIFFERENCE BETWEEN COMFORTBATT® AND ROXUL SAFE‘N’SOUND®?
The difference between ROXUL COMFORTBATT® and ROXUL SAFE‘n’SOUND® is density (weight) and batt size. ROXUL SAFE‘n’SOUND® is denser than COMFORTBATT® and is manufactured to an approximate 3 inch thickness."

"SAFE'n'SOUND® is intended for acoustical and added fire resistance in interior wall applications. Interior walls have no R-value requirements so R-value information is not tracked or published for SAFE'n'SOUND®. We recommend COMFORTBATT® be used in applications requiring thermal value."

It looks like the momentum will be stepping up on this project. There is growing attention, interest and support from my peers to get this DONE!