New Drum/Live Room Design in Chicago, IL

[nmk85roll]

Hello Everyone! First off, let me thank you up front for taking the time to click on my thread and show some interest! This is my first post, but probably easily the 201st hour I have spent on the forum! I've gone through multiple threads, bought Rob's book and read it cover to cover, as well as explored just about every link applicable in the FAQ/Reference sections. Your inputs and feedback are greatly appreciated! Here we go...

Budget: $5000 to $9000
The purpose of this room in order of importance is:
1. Drum Practice Studio
2. Live Tracking Room
3. Bedroom

Yes, I know... bedroom...boring... but I need to think resale for later in life as well. After much thought, it really only changes two things for my situation. First, I need to add a closet, and second, I need to make sure a standard bedroom set could fit in here so unusual wall angles need to be AT least manageable. The good news is, the closet doesn't really need to be a closet for me, I can remove the door off the hinge, or take the door of the track, and just leave open space if that will help with the acoustics. Also, let's just get the floor discussion out of the way. The room will utilize the thick basement slab as the floor. I'll plan do some nice concrete smoothing and finish, but I have two proposed setups, but lets first discuss the MAIN limitation... CEILING HEIGHT!

I have a steal beam that runs across the whole house (see pic1). I could either make my room SUPER small and avoid the beam completely, but that just seems like an awful idea on all levels. Also, I do have some duct work, pipes, etc... towards the back of the room that I would have to work around as well so I'd lose some ceiling height there too. I could have a multi-level ceiling, but I feel that would add a lot of complexity when it comes to sealing. So... my first thought is to just AVOID the beam all together and build a separate ceiling under it which gives me 7'5" to work with. I figured I can have the ceiling joists run in the same direction as the beam, so the beam would eventually be in a pocket between two ceiling joists which would allow me to gain back a few inches with a finished ceiling. Assuming I do an engineered 2x6, with RC, 5/8" sheetrock, green glue, 5/8" sheetrock, that means I would only lose the width of the RC, greenglue, and 2 layers of drywall. So leaving a small gap of at least 1" between the beam and the resilient channel, that would give me an INTERIOR finished ceiling height of 7'2".

pic1.jpg

So that's my main limiting factor for the drum room. Also, if you noticed on the blueprint, the back wall against the unexcavated area and the wall with the window, are both roughed in with vapor barrier with insulation, 2x4s, 1" air gap, and then 10" of concrete. From there, I started messing with the room mode calculators using the 7'2" as my absolute max height and calculating the INTERIOR dimensions of the room. The next limiting factor in my design is the width of the room. As you can see from the blueprint (see basement_blueprint), my ejector pit will limit where that wall can go. This is the ORANGE wall in my crappy Sketchup drawing. This wall can always move inward, but that maximum distance from the opposite concrete window wall is 12'0". So if we assume a UL U423 design (STC 61...even though STC isn't a great measure) for walls that are 6.5" thick, that gives me a MAX WIDTH of 10'11". From there, it was just a matter of deciding the length of the room based on the calculations from room mode calculator. Upon doing so I realized I could hit one of the good ratios of 1:1.5:2.1. This would give me a room of 7.2' x 10'10" x 15'1" which is what I'm proposing as my best option. Ironically, the Bonello response didn't look all that great on bobgolds.com calculator, but it seemed ok on amcoustics.com calculator. Both are shown below as well. I have the option of shrinking the length of the room to 13'7" which cleans of the Bonello nicely and still passes everything else, but I'm guessing I'm better off with the added space/volume?

basement_blueprint.jpg

RoomMode1.jpg

RoomMode2.jpg

Room Mode Alt.jpg

Now that we have the interior dimensions proposed, I have two options to integrate the closet...

Option1.jpg

Option 1: One is just blocking out a small 3.5' area next to the concrete column intrusion (see option1). In doing so, I know I am probably messing with the room modes as the length for part of the room is now effectively 13'1". However, when using 13'1" in the room calculators, everything passes including the Bonello response. I lose minimal space/volume especially if I don't put up a door and the only added material would be a short 2' wall of the closet, which would still be inside the double leaf wall of the outer shell.

Option2.jpg

Option 2: Obviously I know 90 degree angles are bad. So the though crossed my mine to add a separate wall for the back wall on an angle that would eliminate two of the 90 degree corners and then I could put the close on a slant. The angle would be around 14 degrees which is more than the minimum 12 degrees that I see written everywhere. The down side to this is I lose about 5 sq ft or 37 cubic feet compared to the other solution (and that's counting it with the closet door ON).

OptionsSideBySide.jpg

As for wall construction, If I'm going to utilize the two existing RED walls, I will just add proper insulation instead of the crap already in there, add an RC, then 5/8" sheet rock, green glue, then another 5/8' sheet rock. Correct me if I'm wrong but that should be a MASS-AIR-MASS double leaf system where the concrete is one MASS, the 1" air gap and 2x4s with insulation are the AIR, and the RC, and 2 layers of sheet rock are the other MASS. The ORANGE wall and GREEN wall would be the same except it would have another layer of 5/8" sheet rock, green glue, and 5/8" sheet rock on the back side of 20g steel studs, 24" OC. I know 25 gauge is better, but based on what I read I need 20 gauge here for load bearing so I can support the ceiling. The RCs for the RED walls would be at 24" OC and 16" OC for the GREEN and ORANGE wall to be opposite of the stud spacing. (I'm pretty sure I read that somewhere...) If you all recommend Option 2 for the room design with the slanted wall, I'm curious on how you think I should build that wall to incorporate the closet properly.

As for the door, I need some advice here. As stated, the main purpose of this is a drum practice room and then a tracking room because I know people will come play, jam, and want to watch. So for my friends and family to enjoy this adventure, I will need to add a big window on the GREEN wall, probably around 72" by 42". But considering I need to add one of the SUPER doors or double door as outlined in Rod's book, I'm wondering if I should just pony up and get the double sliding doors to accomplish both tasks. I feel like there might be fewer possibilities for error during install as it's only one opening now that needs to be sealed instead of 2 for a double window and in theory 2 for the double door. Thoughts?

There are two other obstacles we need to address from that pic1 as well. I have an emergency window and an electrical panel that needs to be dealt with. For the electrical panel, I'm thinking of just building a separate framed door with sturdy hinges and a magentic clasp that will use the same insulation, two layers of sheet rock, and green glue. That way it can still be "accessible" but I can seal the crap out of it on the inside. I don't need it to look pretty. As for the window, I'm not sure what to do here. The good thing is my property line is 25' from the window, and the neighbor is at least another 20' beyond that. The down side is that both AC units are on that side of the house so I'm probably more worried about sound getting in. I'd test it using an SPL meter, but considering its -12 right now in Chicago, I can't turn them on

Electrical will all be done surface mount with one small cutout to bring power in. I'll draw that up later. HVAC will be done by attaching to the pre-existing unit. I have the luxury of TWO HVAC units, one for upstairs and one for my main floor. I was planning to tie this into the UPSTAIRS one as its highly uncommon for anyone to be upstairs other than sleeping. That way I can use a damper to decide to add air flow to the studio when only in use. I also plan to do silencer boxes, which I will draw up later as well. I imagine I will have these either on the ceiling outside the interior framing or I can put them on the outside of the ORANGE wall close to the furnace. More to come on this later...

So in summary, my main questions are:

1. Should I go with the 7'2" ceiling height which will avoid the complications of the beam and existing HVAC, or spend more money to vary the ceiling as much as possible to maximum height closer to the floor joists when possible?

2. Do you agree with my assessment on room dimensions and maximizing the room size to hit the 1:1.5:2.1 ratio even though the Bonello response isn't all that great?

3. Is the rectangular room with maximum volume the better way to go vs. the slanted back wall which takes up more space? And if you think the slanted is the right option, how would you go about constructing that back wall then with the 10" concrete and 2x4 framing already existing?

4. Do you agree with the planned double leaf construction on the two existing RED walls as well as the additional ORANGE and GREEN wall?

5. Do you think it's worth getting the double sliding doors or stick to a separate window and separate door configuration?

6. How should I deal with the electrical panel and window on the pre-existing exterior wall against the concrete?

Truly appreciate all you help and feedback everyone!!!

[Soundman2020]

HI there "nmk85roll", and Welcome!

I have a steal beam that runs across the whole house (see pic1).

Ouch! That's a problem, for sure.

Also, I do have some duct work, pipes, etc... towards the back of the room that I would have to work around as well so I'd lose some ceiling height there too.

Unless you move the duct-work to another location... It might be an option.

I could have a multi-level ceiling, but I feel that would add a lot of complexity

Not necessarily. It will add SOME complexity, yes, but it doesn't have to be overwhelming. If your contractor is any good, their framers will be able to build that without too much hassle.

my first thought is to just AVOID the beam all together and build a separate ceiling under it which gives me 7'5" to work with.

... and would also greatly reduce the available acoustic height of the ceiling, which is not a good idea in general, and even worse if you plan to play/track drums in there! Drums under a low ceiling almost never sound good: The overheads end up very close to the reflective surface, thus inducing major comb filtering in there response, and the short flight time for reflections going up and coming back into the snare and tom mics makes even the best drum kit sound like a child's toy. You can deal with some of that by vary careful mic placement, EQ, and perhaps some judicious use of effects, but the "tiny dull closet" sound never truly goes away.

I'd look for a solution that allows you to maximize the ceiling height for at least one large section of the room, under which the drums will be played and tracked, even if other parts of the room have a lower ceiling.

I figured I can have the ceiling joists run in the same direction as the beam, so the beam would eventually be in a pocket between two ceiling joists ....

That might work for the beam, but what about the ducts? How wide are the ducts? You do need a certain minimum spacing between your joists... the ducts might prevent you from getting that. Plus, having your ducts in close proximity to the upper side of the ceiling leaf, is a recipe for disaster... Do the math to figure out the MSM resonance for that situation, and it will be an eye-opener for you...

Assuming I do a 2x4,

Ummm..... don't look now, but there's no way you are going to span that distance with 2x4s and two layers of drywall plus GG and RC. You are going to need 2x6 at least, and perhaps even 2x8. That's several more inches that you'd be chopping of your acoustic ceiling height...

that would give me an INTERIOR finished ceiling height of 7'2".

... and would place your overhead mics within inches of your hard, solid, rigid, massive, reflective ceiling...

I started messing with the room mode calculators

It's a live room, not a control room. There's no need at all to worry about room ratios. As long as there's no obvious direct relationship between room dimensions, you are fine (eg, width is the same as height, or length is twice the width, etc.)

So if we assume a UL U423 design (STC 61...even though STC isn't a great measure)

Right! STC isn't useful at all for predicting isolation of studios... and ESPECIALLY irrelevant for drums. A very large portion of the energy put out by a drum kit is totally outside the very small range measured for STC ratings.

Also, you didn't say how much isolation you need, how much you have at present with the existing construction, or how loud you will be. So even if there was a direct one-to-one correspondence between STC and real world isolation in dB, there's still no way to determine if 61 dB of isolation is enough, too much, or about right!

So if we assume a UL U423 design

And what design would you use for your ceiling, to get the same "STC-61" level? And doors? And the window? And the HVAC? And the electrical system? Isolation of a room is only as good as the weakest point. If you spec U423 for the walls, then you should be specifying the equivalent for all of the other parts of your design as well. There's no point in having (for example) 50 dB isolation in the walls if your ceiling only gives you 40...., or your doors work out to 35....

This would give me a room of 7.2' x 10'10" x 15'1" which is what I'm proposing as my best option.

For that room, considering it is a live room meant for drums, your best option would be the one that gives you the highest possible ceiling, widest possible width, and longest possible length, regardless of what room mode calculators tell you. Control rooms need good ratios: live rooms don't. It's basically irrelevant for live rooms. It's worth taking a look, yes, but not worth using it to make decisions about length, width or height, unless it shows something really, really bad.

but I'm guessing I'm better off with the added space/volume?

Absolutely! Always go for more room volume if you possibly can. Even in a control room I would rather have more volume that hit a certain ratio perfectly.

I know I am probably messing with the room modes

Irrelevant... see above!

Option 2: Obviously I know 90 degree angles are bad

Actually, that's a myth! There¿s nothing wrong with 90° angles. Take a look at Abbey Road's main live room, for example: 90° angles everywhere! I hardly think you'd call that room "bad"...

add proper insulation instead of the crap already in there, add an RC, then 5/8" sheet rock, green glue, then another 5/8' sheet rock. Correct me if I'm wrong but that should be a MASS-AIR-MASS double leaf system where the concrete is one MASS, the 1" air gap and 2x4s with insulation are the AIR, and the RC, and 2 layers of sheet rock are the other MASS

Right, but did you do the math to check that the MSM FREQUENCY is correct for your application? And that the overall design will provide the correct ISOLATION for what you need?

will need to add a big window on the GREEN wall, probably around 72" by 42".

Not a problem! You can have windows if you want. As long as you ensure that you are getting the same (or better) isolation where the windows are, it's not an issue.

I'm wondering if I should just pony up and get the double sliding doors to accomplish both tasks.

That depends on where you need to have glass! If you need it in BOTH places to provide the sight lines that you need, then do both. If you only need it where the door will be, then do it there.

The advantage of sliding glass doors is that you get a lot of view, as there's a lot of glass in there: floor to ceiling, and the full width of both doors. There are two disadvantages: 1) is the cost: acoustic rated sliding glass doors are not cheap ! ( ). And 2) is the acosutic treatment issue in side the room: That's a very large area of solid, rigid, massive, reflective surface that you cannot treat: It sort of defeats the purpose of having glass there, if you have to then roll a large gobo in front of it when you are tracking, to get the acoustics under control.

For the electrical panel, I'm thinking of just building a separate framed door with sturdy hinges and a magentic clasp that will use the same insulation, two layers of sheet rock, and green glue. That way it can still be "accessible" but I can seal the crap out of it on the inside.

Check your local electrical code, and talk to your building inspector: that might not be permitted. In some places, the electrical panel must be visible and accessible, to enable emergency shut-off.

As for the window, I'm not sure what to do here.

That's a legal requirement. According to your drawings, that's an emergency egress window, that will save your butt in the event of a fire or other disaster elsewhere in the house that prevents you getting out the front door. You cannot cover it. You MIGHT be allowed to place another operable window in front of it (such as a sliding glass door, for example) that leaves it visible and accessible. Once again, check your local building code, and talk to your local building inspector. Also check your home-owner's insurance policy: You might find a clause hidden 27 levels deep in the fine print that says something about in the event that you disable or interfere with emergency exists blah-blah-blah, the insurance company washes their hands entirely, you get nothing, and you also then become legally liable for all damages and expenses, "including but limited to ...." blah blah blah. Make VERY sure you check that! Ditto for your electrical panel.

Let's say the worst happens: there's an electrical fire in your house when you have visitors there, and they can't shut off the power because they can't find the electrical panel (you hid it behind that "door" thingy....), and one of them dies in the resulting fire because they could not get out the egress window (because you illegally blocked it...) , while another spends months in hospital recovering from burns and smoke inhalation: All of that is on your head. Your insurance won't pay you a cent for the damage to the house, since your electrical panel was illegal, and they won't pay a cent for the funeral, or for the medical expenses. You will have to foot the bill for all that, and if the surviving visitor sues you for damages, you will have to pay that too. Plus, you would probably be criminally or civilly liable for the death: Manslaughter, not murder, but liable nevertheless..... This not a happy picture.... And then your neighbors might decide to sue you too, for emotional suffering or whatever, because they got scared when they watched your house burn to the ground... You can keep on adding to thos scenario, and you get to pay every last cent, with no help from insurance! So yes, it's important to check your building code, fire code, electrical code, and talk to your building inspector to get his OK for whatever it is you plan to do. And of course, do make sure to get all your permits and inspections!

The good thing is my property line is 25' from the window, and the neighbor is at least another 20' beyond that.

If you are not at all concerned about isolating your room, then why go to all the trouble of isolating it? That's a lot of money, time and effort you'd be spending, all for nothing, if you don't actually need to isolate! If the current level of isolation provided by that egress window is fine and sufficient, and since that window is what will define your TOTAL isolation, then why isolate the rest?

1. Should I go with the 7'2" ceiling height which will avoid the complications of the beam and existing HVAC, or spend more money to vary the ceiling as much as possible to maximum height closer to the floor joists when possible?

If that were my room, and I wanted to track drums in it, I would go wit an "inside out" ceiling that is as high as possible (acoustically), at least for the area where I plan to play/track drums.

2. Do you agree with my assessment on room dimensions and maximizing the room size to hit the 1:1.5:2.1 ratio even though the Bonello response isn't all that great?

No, because fine-tuned room ratios are not applicable to live rooms, only control rooms.

3. Is the rectangular room with maximum volume the better way to go

Yes.

4. Do you agree with the planned double leaf construction on the two existing RED walls as well as the additional ORANGE and GREEN wall?

Only if you plan to do two-leaf construction around the ENTIRE room, including all walls, the ceiling, the doors and the windows, as well as correctly dealing with the electrical system and HVAC system.

5. Do you think it's worth getting the double sliding doors or stick to a separate window and separate door configuration?

IF you can afford the large extra cost, and if you need the glass in that location, and if you can figure out how to deal with the acoustic treatment issue of that large area of glass, then yes. Otherwise, no. You could site-build a par of back-to-back normal hinged studio doors with glass in them, for much, much less cost than a pair of acoustic rated sliding glass doors.

6. How should I deal with the electrical panel and window on the pre-existing exterior wall against the concrete?

Check your local building code to find out what restrictions apply, talk to your local building inspector, and check your insurance policy. Based on the outcome from that, you can decide which options are open to you, then plan accordingly.

I hope I haven't scared you with all of the above! Your situation is complex, and that's the reason for my musings and warnings. You probably can make a good live room out of this, is you do it all correctly. I'm just trying to point out the issues, so you can deal with them!


- Stuart -

[nmk85roll]

Here are some simple SPL measurements I took using a frequency sweep through a Sonos5 speaker and an SPL meter app on my phone. I know this won't be spot on accurate, but it was really for me to understand the DIFFERENCE in a measurement taken from inside vs. outside the house to get an idea of my current isolation and what I'll need to target. I measured with the phone about 6 inches away from the speaker for the INSIDE reference point. OUTSIDE was taken outside my house, with the phone about 3 feet above the metal grate and escape window. The Office measurement was taken at 3 feet above the floor in my office, which is the room directly above where I want the drum studio to go.

I'll be honest to say that originally I was surprised I only got 20dB of isolation from the window, but once I thought about it, I guess 20dB if fairly average. And considering the concrete walls don't apply here, it would be something similar to a standard wall or window configuration. Either way, the window will need some treatment. I'm thinking to have it just be a removable window plug with two handles screwed to the front side and two swivel latches on either side of the window to keep it in place that I can just slide over the plug when it put it in. That make sense? so my question is:

What type of construction should I do for the Window Plug? Is there any point to framing it like a door and using a resilient channel on this or is it better to just have it be a massive piece of a few sheets of MDF or drywall with a layer or two of plywood inbetween for structure? Probably though some insulation on the back of it that would fill the cavity from the window sill and then just have a lot of weather strip or other sealing mechanism on the inside of the window frame to the plug fits tightly. Any ideas?

Inside_Sweep.jpg

Outside_Sweep.jpg

Office_Sweep.jpg

[nmk85roll]

Stuart! Thanks for all these responses! Let me craft up another post tonight to answer some of this. Didn't want you to think I ignored it after posting those SPL graphs

HI there "nmk85roll", and Welcome!

I have a steal beam that runs across the whole house (see pic1).

Ouch! That's a problem, for sure.

Also, I do have some duct work, pipes, etc... towards the back of the room that I would have to work around as well so I'd lose some ceiling height there too.

Unless you move the duct-work to another location... It might be an option.

I could have a multi-level ceiling, but I feel that would add a lot of complexity

Not necessarily. It will add SOME complexity, yes, but it doesn't have to be overwhelming. If your contractor is any good, their framers will be able to build that without too much hassle.

my first thought is to just AVOID the beam all together and build a separate ceiling under it which gives me 7'5" to work with.

... and would also greatly reduce the available acoustic height of the ceiling, which is not a good idea in general, and even worse if you plan to play/track drums in there! Drums under a low ceiling almost never sound good: The overheads end up very close to the reflective surface, thus inducing major comb filtering in there response, and the short flight time for reflections going up and coming back into the snare and tom mics makes even the best drum kit sound like a child's toy. You can deal with some of that by vary careful mic placement, EQ, and perhaps some judicious use of effects, but the "tiny dull closet" sound never truly goes away.

I'd look for a solution that allows you to maximize the ceiling height for at least one large section of the room, under which the drums will be played and tracked, even if other parts of the room have a lower ceiling.

I figured I can have the ceiling joists run in the same direction as the beam, so the beam would eventually be in a pocket between two ceiling joists ....

That might work for the beam, but what about the ducts? How wide are the ducts? You do need a certain minimum spacing between your joists... the ducts might prevent you from getting that. Plus, having your ducts in close proximity to the upper side of the ceiling leaf, is a recipe for disaster... Do the math to figure out the MSM resonance for that situation, and it will be an eye-opener for you...

Assuming I do a 2x4,

Ummm..... don't look now, but there's no way you are going to span that distance with 2x4s and two layers of drywall plus GG and RC. You are going to need 2x6 at least, and perhaps even 2x8. That's several more inches that you'd be chopping of your acoustic ceiling height...

that would give me an INTERIOR finished ceiling height of 7'2".

... and would place your overhead mics within inches of your hard, solid, rigid, massive, reflective ceiling...

I started messing with the room mode calculators

It's a live room, not a control room. There's no need at all to worry about room ratios. As long as there's no obvious direct relationship between room dimensions, you are fine (eg, width is the same as height, or length is twice the width, etc.)

So if we assume a UL U423 design (STC 61...even though STC isn't a great measure)

Right! STC isn't useful at all for predicting isolation of studios... and ESPECIALLY irrelevant for drums. A very large portion of the energy put out by a drum kit is totally outside the very small range measured for STC ratings.

Also, you didn't say how much isolation you need, how much you have at present with the existing construction, or how loud you will be. So even if there was a direct one-to-one correspondence between STC and real world isolation in dB, there's still no way to determine if 61 dB of isolation is enough, too much, or about right!

So if we assume a UL U423 design

And what design would you use for your ceiling, to get the same "STC-61" level? And doors? And the window? And the HVAC? And the electrical system? Isolation of a room is only as good as the weakest point. If you spec U423 for the walls, then you should be specifying the equivalent for all of the other parts of your design as well. There's no point in having (for example) 50 dB isolation in the walls if your ceiling only gives you 40...., or your doors work out to 35....

This would give me a room of 7.2' x 10'10" x 15'1" which is what I'm proposing as my best option.

For that room, considering it is a live room meant for drums, your best option would be the one that gives you the highest possible ceiling, widest possible width, and longest possible length, regardless of what room mode calculators tell you. Control rooms need good ratios: live rooms don't. It's basically irrelevant for live rooms. It's worth taking a look, yes, but not worth using it to make decisions about length, width or height, unless it shows something really, really bad.

but I'm guessing I'm better off with the added space/volume?

Absolutely! Always go for more room volume if you possibly can. Even in a control room I would rather have more volume that hit a certain ratio perfectly.

I know I am probably messing with the room modes

Irrelevant... see above!

Option 2: Obviously I know 90 degree angles are bad

Actually, that's a myth! There¿s nothing wrong with 90° angles. Take a look at Abbey Road's main live room, for example: 90° angles everywhere! I hardly think you'd call that room "bad"...

add proper insulation instead of the crap already in there, add an RC, then 5/8" sheet rock, green glue, then another 5/8' sheet rock. Correct me if I'm wrong but that should be a MASS-AIR-MASS double leaf system where the concrete is one MASS, the 1" air gap and 2x4s with insulation are the AIR, and the RC, and 2 layers of sheet rock are the other MASS

Right, but did you do the math to check that the MSM FREQUENCY is correct for your application? And that the overall design will provide the correct ISOLATION for what you need?

will need to add a big window on the GREEN wall, probably around 72" by 42".

Not a problem! You can have windows if you want. As long as you ensure that you are getting the same (or better) isolation where the windows are, it's not an issue.

I'm wondering if I should just pony up and get the double sliding doors to accomplish both tasks.

That depends on where you need to have glass! If you need it in BOTH places to provide the sight lines that you need, then do both. If you only need it where the door will be, then do it there.

The advantage of sliding glass doors is that you get a lot of view, as there's a lot of glass in there: floor to ceiling, and the full width of both doors. There are two disadvantages: 1) is the cost: acoustic rated sliding glass doors are not cheap ! ( ). And 2) is the acosutic treatment issue in side the room: That's a very large area of solid, rigid, massive, reflective surface that you cannot treat: It sort of defeats the purpose of having glass there, if you have to then roll a large gobo in front of it when you are tracking, to get the acoustics under control.

For the electrical panel, I'm thinking of just building a separate framed door with sturdy hinges and a magentic clasp that will use the same insulation, two layers of sheet rock, and green glue. That way it can still be "accessible" but I can seal the crap out of it on the inside.

Check your local electrical code, and talk to your building inspector: that might not be permitted. In some places, the electrical panel must be visible and accessible, to enable emergency shut-off.

As for the window, I'm not sure what to do here.

That's a legal requirement. According to your drawings, that's an emergency egress window, that will save your butt in the event of a fire or other disaster elsewhere in the house that prevents you getting out the front door. You cannot cover it. You MIGHT be allowed to place another operable window in front of it (such as a sliding glass door, for example) that leaves it visible and accessible. Once again, check your local building code, and talk to your local building inspector. Also check your home-owner's insurance policy: You might find a clause hidden 27 levels deep in the fine print that says something about in the event that you disable or interfere with emergency exists blah-blah-blah, the insurance company washes their hands entirely, you get nothing, and you also then become legally liable for all damages and expenses, "including but limited to ...." blah blah blah. Make VERY sure you check that! Ditto for your electrical panel.

Let's say the worst happens: there's an electrical fire in your house when you have visitors there, and they can't shut off the power because they can't find the electrical panel (you hid it behind that "door" thingy....), and one of them dies in the resulting fire because they could not get out the egress window (because you illegally blocked it...) , while another spends months in hospital recovering from burns and smoke inhalation: All of that is on your head. Your insurance won't pay you a cent for the damage to the house, since your electrical panel was illegal, and they won't pay a cent for the funeral, or for the medical expenses. You will have to foot the bill for all that, and if the surviving visitor sues you for damages, you will have to pay that too. Plus, you would probably be criminally or civilly liable for the death: Manslaughter, not murder, but liable nevertheless..... This not a happy picture.... And then your neighbors might decide to sue you too, for emotional suffering or whatever, because they got scared when they watched your house burn to the ground... You can keep on adding to thos scenario, and you get to pay every last cent, with no help from insurance! So yes, it's important to check your building code, fire code, electrical code, and talk to your building inspector to get his OK for whatever it is you plan to do. And of course, do make sure to get all your permits and inspections!

The good thing is my property line is 25' from the window, and the neighbor is at least another 20' beyond that.

If you are not at all concerned about isolating your room, then why go to all the trouble of isolating it? That's a lot of money, time and effort you'd be spending, all for nothing, if you don't actually need to isolate! If the current level of isolation provided by that egress window is fine and sufficient, and since that window is what will define your TOTAL isolation, then why isolate the rest?

1. Should I go with the 7'2" ceiling height which will avoid the complications of the beam and existing HVAC, or spend more money to vary the ceiling as much as possible to maximum height closer to the floor joists when possible?

If that were my room, and I wanted to track drums in it, I would go wit an "inside out" ceiling that is as high as possible (acoustically), at least for the area where I plan to play/track drums.

2. Do you agree with my assessment on room dimensions and maximizing the room size to hit the 1:1.5:2.1 ratio even though the Bonello response isn't all that great?

No, because fine-tuned room ratios are not applicable to live rooms, only control rooms.

3. Is the rectangular room with maximum volume the better way to go

Yes.

4. Do you agree with the planned double leaf construction on the two existing RED walls as well as the additional ORANGE and GREEN wall?

Only if you plan to do two-leaf construction around the ENTIRE room, including all walls, the ceiling, the doors and the windows, as well as correctly dealing with the electrical system and HVAC system.

5. Do you think it's worth getting the double sliding doors or stick to a separate window and separate door configuration?

IF you can afford the large extra cost, and if you need the glass in that location, and if you can figure out how to deal with the acoustic treatment issue of that large area of glass, then yes. Otherwise, no. You could site-build a par of back-to-back normal hinged studio doors with glass in them, for much, much less cost than a pair of acoustic rated sliding glass doors.

6. How should I deal with the electrical panel and window on the pre-existing exterior wall against the concrete?

Check your local building code to find out what restrictions apply, talk to your local building inspector, and check your insurance policy. Based on the outcome from that, you can decide which options are open to you, then plan accordingly.

I hope I haven't scared you with all of the above! Your situation is complex, and that's the reason for my musings and warnings. You probably can make a good live room out of this, is you do it all correctly. I'm just trying to point out the issues, so you can deal with them!


- Stuart -

[nmk85roll]

Stuart,

Here is what I've collected from your response. And probably a few follow up questions as well. Let's start with the ceiling first.

1. I need to do everything possible to maximize the height in this room. I measure the height by those ducts and plumbing in the back. Basically, I can't move that duct, it's the main vein for my upstairs HVAC. With that being said, the height below it is 7'10.5". I'll have to move one of the ventilation pipes or two, but that seems doable after talking to a few contractors. The height to the regular floor joists are 8'6. So if I maximize my ceiling space, I'd only have three different heights, and one would technical just be the soffit for the beam anyway. So with this in mind, do you suggest just making the soffit for the beam alone and utilizing that 2 feet long space for more volume as well? Or is that creating a small cavity in which I should just soffit that whole area with the beam instead so it would be about 2.5" long?

Ceiling_Cross_Section.jpg

2. You must have caught my post before I editted the comment about 2x4's on the ceiling That was an error, and I was proposing that i use 2x6 beams instead. For a 11' span its cutting it close so as you suggest, 2x8 might be better especially if I need to go 24" OC to get around that duct work. I'll review this with my architect. However, this starts me to ask the bigger question. Instead of trying to construct a whole separate ceiling support by the load bearing studio walls, would I be better off using the existing 12" I joists to support the double drywall for the ceiling and use RCs or some other isolators, insulation, etc... ?

3. As for how much isolation I need, take a look at my post above with those SPL measurements. My style of playing rarely gets above 110dB so getting 60dB of isolation from my office or outside would be ideal. Realistic? I'll let you scathe me on that Bottom line, I do need more isolation between the studio and the office and outside.

4. You mentioned doing a MSM FREQUENCY calculation... this is new to me. I tried doing some googling, but didn't seem to come up with how to do the math. Could you point me to something where I could calculate this out and do my due diligence? Thank you!

5. The door to seal the electrical panel is permitted as long as its "easily opened" according to my village inspector. He said I may have to put a sticker on it to say the panel is there, but he was going to check. I don't care about a sticker if it makes the room sound good!

6. As for the egress window, it appears I did not explain myself properly. I know what its for and why I can't wall around it. What I was proposing is what I've read some other guys do with that window plug, which I tried to describe in my post above. A removable wall plug, 44''x44" (same size as window) that I would only put up while playing in the studio, maybe only even at early/late hours. You bring up a valid concern about my home owners insurance, but I actually called my agent and he said it wouldn't remotely be a problem because I have 3 other egress windows in the basement, one which is only about 20 feet away from this one in question. So... the main question is, what do you suggest for the construction of this plug? all mdf,drywall, plywood?

Thanks so much for your time in reading this and responding! You haven't scared me yet

[Soundman2020]

Here are some simple SPL measurements I took using a frequency sweep through a Sonos5 speaker and an SPL meter app on my phone. I know this won't be spot on accurate,

Right! Not very accurate at all, but it does help to get an idea.

it was really for me to understand the DIFFERENCE in a measurement taken from inside vs. outside the house to get an idea of my current isolation and what I'll need to target.

For a rough idea, that's fine. When you get a better sound level meter then you'll be able to do it more accurately.

I measured with the phone about 6 inches away from the speaker for the INSIDE reference point.

That should be done at 3 feet. That's the standard distance for acoustic measurements of speakers. At 6" you run the risk that you were not measuring the sound field correctly, as it probably had not merged fully: the woofer and tweeter put out very different sound fields, and you need some distance before you can be sure they have fully merged and smoothed out, and that the artifacts from the speaker face and edges have also smoothed over a bit. By 3 feet, that should be fine for most speakers. Try running the test again, if you want, and measure at 3 feet this time.

OUTSIDE was taken outside my house, with the phone about 3 feet above the metal grate and escape window. The Office measurement was taken at 3 feet above the floor in my office, which is the room directly above where I want the drum studio to go.

That's fine. It's better to take many measurements in various places around the exterior, some up close like you did, some further back, and in several directions, and at several heights above the ground. since the sound field can vary due to a whole bunch of things. If you take several measurements like that, you get a better idea of how well the isolation is working.

I'll be honest to say that originally I was surprised I only got 20dB of isolation from the window,

Yup. That's about right for a typical thin glass window that is operable. It's very hard to get good seals on an operable window, and seals are critical for isolation. So that's typical. If that were a fixed pane, non-operable window, you might have got 25 or so, and if the glass were decently thick, in a good solid frame, perhaps even 28. But going beyond that is tough with a single-leaf.

I'm thinking to have it just be a removable window plug with two handles screwed to the front side and two swivel latches on either side of the window to keep it in place that I can just slide over the plug when it put it in.

Once again, check your building code: that probably isn't legal. The emergency egress path usually must be unobstructed.

That make sense?

Sort of, but not really. This gets complicated...

With a single-leaf barrier, the law of physics that is applicable for figuring out isolation is very simple, and is called "mass law". It goes like this:

TL(dB)= 20log(M) + 20log(F) -47.2

Where:
M is the surface density of the panel (mass per unit area (kg/m²) ), and
F is the center frequency of the third-octave measurement band.

So all you need to know is the surface density of the barrier, and you can figure out the Transmission Loss (TL) in decibels (dB)for any frequency that you want. There's an even simpler version, called the "empirical mass law equation", that doesn't even need you to choose the frequency: it just gives you an overall estimate for the entire spectrum. It goes like this:

TL(dB) = 14.5 log (Ms * 0.205) + 23 dB

Where: M = Surface Mass in kg/m2

Dead easy. But not very encouraging! Do the math for a few possible barriers and frequencies, and you'll see that you need HUGE amounts of mass to get reasonable isolation. The equation also implies that each time you DOUBLE the mass, you get a paltry increase of 6 dB in isolation. That assumes perfect materials, perfect mounting, perfect conditions, etc. In reality, you get more like 4 to 5 dB each time you double the mass. To put that in perspective, if you have a single sheet of 15mm drywall, that will get you about 25 dB of isolation. So double that, so you have two layers, and that will get you 30 dB. Double it AGAIN (four layers now), and you get 35 dB. Double it AGAIN (you now have 8 layers), and you get 40dB. Double it yet again, for a total of SIXTEEN layers of drywall, and you get 45 dB of isolation. Double it one more time so you can reach 59 dB of isolation, and you now have 32 layers of drywall, which is 48cm thick.

As you can see, a single-leaf barrier isn't much help, unless it is extremely massive and extremely thick. Concrete and brick are about the only two reasonable options. Even though you could get there with 32 layers of drywall, I'd like to know what type of stud you'd use to support that and where you would find drywall nails that are 55 m long....

That's why you are getting such poor isolation from your window: It's just a single-leaf barrier, and not much mass. The concrete is much better, of course, so the window is the weak point.

So, if you wanted to add more mass to that window to get better isolation, you can see why you are fresh out of luck. It ain't gonna do much!

Fortunately, there's another option: do a 2-leaf barrier. This type of isolation barrier is governed by a different set of equations, sometimes called the 2-leaf MSM equations, (where "MSM" means "Mass-Spring-Mass"). This is a much happier outcome, because now you can get as much as 18 dB increase with each mass doubling for some parts of the spectrum. The reason this works so much better, is because it is a tuned resonant system. You have two "leaves" of mass separated by an air gap, which acts like a spring. Hence the MSM name. So for example, two sheets of drywall with an air gap between them, or two panes of glass with an air gap between them. This system is tuned, and will resonate at a certain frequency. At that frequency, it does not isolate at all, and in fact can amplify sound. But at all frequencies starting about twice that frequency (one octave higher), it does isolate, and it isolates a hell of a lot better than a single leaf.

So, you need to create a two-leaf barrier if you want high isolation with a reasonable amount of mass. You'd think that your "window plug" could do that, but there's a catch: to get the resonant frequency down low enough, you need a large air gap, and lots of mass. The general rule of thumb is that the air gap needs to be at least 4" (10 cm), and the mass on each side needs to be at least 25 kg/m2. That implies glass that is at least 10mm thick on each side, plus a 10cm gap. And that's the minimum: you might need more mass and greater depth, depending on other factors, such as the coincidence dip, for example... that's a bit too complicated to explain, but it's another form of resonance in each leaf, that robs you of isolation. It's clearly visible in your own tests, at around 1.5 kHz you can see that the isolation falls off suddenly, then improves again: that's the coincidence dip. You can also see that it is really bad at about 140 Hz: that's probably the resonant frequency of the window itself.

So anyway, that should tell you why a simpoe plug won't work: because you can't get a large enough air gap from a simple plug, and nor can you get enough mass on there. 25 kg/m2 is fine for glass, as you only need 10mm to do that, but for the drywall on the plug itself, you'd need four layers of 15mm drywall to get that amount of mass.... and it would, obviously be a very heavy plug: maybe too heavy to pick up and put in place by one person, and also too heavy to hold in place with a simple catch of some type....

In other words, the only real solution here, is a second window maybe 15 cm away, in a second wall, or at least a massive extension of the existing wall. Not what you wanted to hear, but that's the sad reality.

...would fill the cavity from the window sill and then just have a lot of weather strip or other sealing mechanism on the inside of the window frame to the plug fits tightly.

... and that's the other issue! You nailed it perfectly: sealing. Seals are way more critical than most people think. A single tiny crack under your door, just a couple of mm wide, can totally trash all of the isolation provided by the entire wall! Not intuitive, but true. So you need not just good a seal on your plug, but a PERFECT seal. Since it is impossible to have a perfect seal, you would need at least two, and preferably three, "imperfect" seals. Each of those would need to run around the full perimeter of the plug, unbroken. Then you'd need some form of locking catch that can provide enough pressure on the seals, to ensure that the really do seal tightly....

Not trying to dishearten you! Just pointing out reality...

Hope I didn't trash your evening....

- Stuart -

[nmk85roll]

Thanks Stuart, let me ponder this overnight and do some research on those (minimal) options.

Could you do me favor and comment on the ceiling idea? Would it be better to construct a seperate ceiling with soffitts as discussed or should I suppport it with the current floor joists with some sort of isolation as in part 1 of my earlier post?

Thanks!

Here are some simple SPL measurements I took using a frequency sweep through a Sonos5 speaker and an SPL meter app on my phone. I know this won't be spot on accurate,

Right! Not very accurate at all, but it does help to get an idea.

it was really for me to understand the DIFFERENCE in a measurement taken from inside vs. outside the house to get an idea of my current isolation and what I'll need to target.

For a rough idea, that's fine. When you get a better sound level meter then you'll be able to do it more accurately.

I measured with the phone about 6 inches away from the speaker for the INSIDE reference point.

That should be done at 3 feet. That's the standard distance for acoustic measurements of speakers. At 6" you run the risk that you were not measuring the sound field correctly, as it probably had not merged fully: the woofer and tweeter put out very different sound fields, and you need some distance before you can be sure they have fully merged and smoothed out, and that the artifacts from the speaker face and edges have also smoothed over a bit. By 3 feet, that should be fine for most speakers. Try running the test again, if you want, and measure at 3 feet this time.

OUTSIDE was taken outside my house, with the phone about 3 feet above the metal grate and escape window. The Office measurement was taken at 3 feet above the floor in my office, which is the room directly above where I want the drum studio to go.

That's fine. It's better to take many measurements in various places around the exterior, some up close like you did, some further back, and in several directions, and at several heights above the ground. since the sound field can vary due to a whole bunch of things. If you take several measurements like that, you get a better idea of how well the isolation is working.

I'll be honest to say that originally I was surprised I only got 20dB of isolation from the window,

Yup. That's about right for a typical thin glass window that is operable. It's very hard to get good seals on an operable window, and seals are critical for isolation. So that's typical. If that were a fixed pane, non-operable window, you might have got 25 or so, and if the glass were decently thick, in a good solid frame, perhaps even 28. But going beyond that is tough with a single-leaf.

I'm thinking to have it just be a removable window plug with two handles screwed to the front side and two swivel latches on either side of the window to keep it in place that I can just slide over the plug when it put it in.

Once again, check your building code: that probably isn't legal. The emergency egress path usually must be unobstructed.

That make sense?

Sort of, but not really. This gets complicated...

With a single-leaf barrier, the law of physics that is applicable for figuring out isolation is very simple, and is called "mass law". It goes like this:

TL(dB)= 20log(M) + 20log(F) -47.2

Where:
M is the surface density of the panel (mass per unit area (kg/m²) ), and
F is the center frequency of the third-octave measurement band.

So all you need to know is the surface density of the barrier, and you can figure out the Transmission Loss (TL) in decibels (dB)for any frequency that you want. There's an even simpler version, called the "empirical mass law equation", that doesn't even need you to choose the frequency: it just gives you an overall estimate for the entire spectrum. It goes like this:

TL(dB) = 14.5 log (Ms * 0.205) + 23 dB

Where: M = Surface Mass in kg/m2

Dead easy. But not very encouraging! Do the math for a few possible barriers and frequencies, and you'll see that you need HUGE amounts of mass to get reasonable isolation. The equation also implies that each time you DOUBLE the mass, you get a paltry increase of 6 dB in isolation. That assumes perfect materials, perfect mounting, perfect conditions, etc. In reality, you get more like 4 to 5 dB each time you double the mass. To put that in perspective, if you have a single sheet of 15mm drywall, that will get you about 25 dB of isolation. So double that, so you have two layers, and that will get you 30 dB. Double it AGAIN (four layers now), and you get 35 dB. Double it AGAIN (you now have 8 layers), and you get 40dB. Double it yet again, for a total of SIXTEEN layers of drywall, and you get 45 dB of isolation. Double it one more time so you can reach 59 dB of isolation, and you now have 32 layers of drywall, which is 48cm thick.

As you can see, a single-leaf barrier isn't much help, unless it is extremely massive and extremely thick. Concrete and brick are about the only two reasonable options. Even though you could get there with 32 layers of drywall, I'd like to know what type of stud you'd use to support that and where you would find drywall nails that are 55 m long....

That's why you are getting such poor isolation from your window: It's just a single-leaf barrier, and not much mass. The concrete is much better, of course, so the window is the weak point.

So, if you wanted to add more mass to that window to get better isolation, you can see why you are fresh out of luck. It ain't gonna do much!

Fortunately, there's another option: do a 2-leaf barrier. This type of isolation barrier is governed by a different set of equations, sometimes called the 2-leaf MSM equations, (where "MSM" means "Mass-Spring-Mass"). This is a much happier outcome, because now you can get as much as 18 dB increase with each mass doubling for some parts of the spectrum. The reason this works so much better, is because it is a tuned resonant system. You have two "leaves" of mass separated by an air gap, which acts like a spring. Hence the MSM name. So for example, two sheets of drywall with an air gap between them, or two panes of glass with an air gap between them. This system is tuned, and will resonate at a certain frequency. At that frequency, it does not isolate at all, and in fact can amplify sound. But at all frequencies starting about twice that frequency (one octave higher), it does isolate, and it isolates a hell of a lot better than a single leaf.

So, you need to create a two-leaf barrier if you want high isolation with a reasonable amount of mass. You'd think that your "window plug" could do that, but there's a catch: to get the resonant frequency down low enough, you need a large air gap, and lots of mass. The general rule of thumb is that the air gap needs to be at least 4" (10 cm), and the mass on each side needs to be at least 25 kg/m2. That implies glass that is at least 10mm thick on each side, plus a 10cm gap. And that's the minimum: you might need more mass and greater depth, depending on other factors, such as the coincidence dip, for example... that's a bit too complicated to explain, but it's another form of resonance in each leaf, that robs you of isolation. It's clearly visible in your own tests, at around 1.5 kHz you can see that the isolation falls off suddenly, then improves again: that's the coincidence dip. You can also see that it is really bad at about 140 Hz: that's probably the resonant frequency of the window itself.

So anyway, that should tell you why a simpoe plug won't work: because you can't get a large enough air gap from a simple plug, and nor can you get enough mass on there. 25 kg/m2 is fine for glass, as you only need 10mm to do that, but for the drywall on the plug itself, you'd need four layers of 15mm drywall to get that amount of mass.... and it would, obviously be a very heavy plug: maybe too heavy to pick up and put in place by one person, and also too heavy to hold in place with a simple catch of some type....

In other words, the only real solution here, is a second window maybe 15 cm away, in a second wall, or at least a massive extension of the existing wall. Not what you wanted to hear, but that's the sad reality.

...would fill the cavity from the window sill and then just have a lot of weather strip or other sealing mechanism on the inside of the window frame to the plug fits tightly.

... and that's the other issue! You nailed it perfectly: sealing. Seals are way more critical than most people think. A single tiny crack under your door, just a couple of mm wide, can totally trash all of the isolation provided by the entire wall! Not intuitive, but true. So you need not just good a seal on your plug, but a PERFECT seal. Since it is impossible to have a perfect seal, you would need at least two, and preferably three, "imperfect" seals. Each of those would need to run around the full perimeter of the plug, unbroken. Then you'd need some form of locking catch that can provide enough pressure on the seals, to ensure that the really do seal tightly....

Not trying to dishearten you! Just pointing out reality...

Hope I didn't trash your evening....

- Stuart -

[Soundman2020]

So with this in mind, do you suggest just making the soffit for the beam alone and utilizing that 2 feet long space for more volume as well?

For that situation, it seems that the easiest thing would be to build the ceiling partly inside-out, and partly conventional, but based on the same joist system. So one set of joists, running lengthwise (then can be big: no problem), with "conventional" ceiling on the bottom edge of the joists, for the parts under the duct and beam, and "inside out" modules raised up between the joists in the central section.

That's what I would suggest.


- Stuart -

[nmk85roll]

So with this in mind, do you suggest just making the soffit for the beam alone and utilizing that 2 feet long space for more volume as well?

For that situation, it seems that the easiest thing would be to build the ceiling partly inside-out, and partly conventional, but based on the same joist system. So one set of joists, running lengthwise (then can be big: no problem), with "conventional" ceiling on the bottom edge of the joists, for the parts under the duct and beam, and "inside out" modules raised up between the joists in the central section.

That's what I would suggest.


- Stuart -

Thanks Stuart. I'm meeting with my architect tomorrow to discuss all of this so I'm sure I'll be posting a lot this week. For the ceiling, in general, is it considered better to build a separate new framed ceiling underneath the floor joists for complete isolation instead of using isolation clips and hat channels on the pre-existing floor joists to hang the studio ceiling from? Let's assume the finished ceiling height only changes by 2" so trivial here.

Thanks again for your help! More to come...

[Soundman2020]

I'm meeting with my architect tomorrow to discuss all of this...

Do make sure that your architect clearly understands what "inside-out" construction of the "inner-leaf" is! Most don't... these are not concepts that are commonly used in any type of construction, except in recording studios.... Chances are, he's never heard of them...


- Stuart -

[nmk85roll]

Ok everyone. After much consideration, I'm taking a slightly different approach. I'm going to utilize a larger part of my basement for the Drum/Live room, and then have the bedroom constructed separately. I'm planning to sound proof that as well so in theory I could use it as a second live room. Point being, the Drum Studio can now be around 225 sq feet with a 7'9" finished ceiling. Unfortunately I still have to deal with another egress window, but I lose some of the complexity with pre existing duct work and the electrical panel in the drum room. i'm also keeping very small closets in both for qualifying as a bedroom in case of resale. Because of this expansion, my budget has about doubled so we are trying to keep this all under $20k now.

A few things to note:

1. I've decided to go with the sliding doors for entry into the studio. I really do like the look of them, and it makes it easier for others to view what's going on in the studio without having to take the loudness of the drumkit. Now, when I might actually be recording, I have no problem putting some type of treatment in front of the window even if it blocks the view. What do you recommend for this type of application?

2. For the smaller live room/bedroom, I went with a air lock system for the doors. I'm planning to buy that acoustic seal kit for the bedroom door as well, which between that and the 42"x42" airlock should have good isolation from the rest of the basement. I can always add mass to the doors as well per Rod's book. I'm planning for 3' doors to allow for equipment to easiliy be moved in and out, including the furnace room which will also be isolated through the airlock as well.

3. I'm going to add a window inbetween the two live rooms now to plan ahead for future use. I can add a dinky privacy curtain on the inside when used as a bedroom, or use a more standard treatment similar to my questions in #1 if I will be recording in this room as well.

4. For the egress windows, based on Stuart's recommendation above, I'm now looking at adding a second egress window with some thicker glass that will be located in the framed wall to establish a MSM system for those windows.

5. Apparently, I'm great at understanding all of this in 2D, but when you add the 3rd dimension, and connect a wall to another wall, or wall to floor, I don't quite understand how to construct that properly. For example,
a. For the walls, do you anchor those DIRECTLY into the concrete floor? No need for neoprene pads or some other type of isolation?
b. How do you seal the MSM ceiling system from the wall with the sliding door? i.e. if you are standing outside the studio and look down the 2x6s towards the egress window, technically you
can see down to the concrete wall. Do you apply drywall all the way up the exterior wall to the floor joists and underlayment of my 1st floor? I struggle with the physics principles here of
flanking....

6. HVAC silencers... I've done a lot of research here and it's still fuzzy to me. Correct me if I'm wrong but the goal of a silencer box is to slow down air velocity to reduce noise inside your studio, correct? Do these silencer boxes help with sounds going BACK through the HVAC system? In what situations do you need one per duct vs. two per duct (one on inner leaf, one on outer)? Also, the whole 2x the area of the inlet is needed for the outlet/register... i'm setting conflicting reports if that 2x Area is needed THROUGHOUT the entire silencer box, or just at the outlet/register before entering the studio? (and vice versa for the return duct) And compared to actual manufactured "duct silencers", which ones provide better isolation? Seems the cost of duct silencers has come down a lot from the threads here in 2008 where people said they are expensive, especially considering how expensive duct liner is.

Thanks everyone!

Studio15a-Model.pdf

Studio15a.jpg

[nmk85roll]

Little update guys. I've decided to change to a double wall construction as I could give up the extra few inches in real estate. Now that I'm not using isolation clamps and furring channels, it really didn't hurt my area all that much. I also decided to splay the close as to avoid and small angles, it takes up just an additional 0.5sqfeet for me to do that and looks a lot nicer than the weird angled box closet.

One MAIN QUESTION I have is the air lock. I know this topic has come up about a 4 leaf system, but the larger space negates any huge negative affect. My questions is regarding to two walls I drew as SINGLE stud walls. I shouldn't need to make these double correct? I didn't really see a point because i'm not doing back to back doors. So should I just double drywall and green glue on both sides? The Door to the bedroom will also have a acoustic jamb/seal kit.

Thanks for the help!

[nmk85roll]

HA! I think I realized why no one was replying... the pictures didn't load in the thread and you had to download. And all this time I thought you were just ignoring me cause I'm a newbie

Sorry guys! Here is the JPG version of the studio.

Studio15final-Model.jpg

[nmk85roll]

Back to my original question, how do I get this airlock designed properly. Option 1 was my original, but I realized the air gap has a path directly into the bedroom because I don't want the door opening into it. My thought with option 2 was that the air lock becomes part of the MSM air gap. Because the doors take up most of the surface area, I was thinking I could just add fabric over the insulation on the one side without the door to avoid any triple leaf affect with drywall.

Need some help here gents. Thanks!

airlock_option1.jpg

airlock_option2.jpg

[nmk85roll]

So we were getting ready to start doing some sealing of the outer leaf today before framing the new inner leaf, and I realize parts of my pre-existing framing are actually touching my foundation wall, and in some cases, sloppily sealed with foam to the concrete. My thought is that I can no longer use the existing framing as inner leaf because its now coupled to the foundation outer leaf. Everyone agree here?

If this is the case, I'm guessing my only option is to now build another wall that would be my interior leaf and leave this existing wall with insulation as part of the outer leaf and air gap in an MSM system. Sucks that I lose 4.5" in every direction now, but I rather do this build right from the start instead of discovering late in the game that I don't have the isolation I planned for.

Maybe now I consider doing inside out walls on every wall in the studio now? I'll have to do a lot more research on this type of system now. Originally the thought of not having a hard surface for people to accidentally lean on bothered me.

Do you all agree? Is there something I'm not thinking about here? Thanks guys!

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