Ceiling Sound Isolation Advice

Hi, I am currently adding one room to project studio located in a warehouse space, which would serve as my live room. However, on 1 or 2 nights per weeks, air traffic is diverted to my part of the town and airplane noises can be heard in the room. The room is in the 2nd floor with an exposed ceiling (basically just wood boards and roof) approximately 10'x16' in size and the height of the room is approximately 11.' I am hoping to get some advice on how I can treat the ceiling so that I can use that room for recording. I've been researching isolation designs online and most of them suggest a 2 layer drywall ceiling filled in with insulation. Unfortunately, while I can attach drywall directly to the boards, I am only allowed to install a suspension tile ceiling. Would using a suspension tile ceiling with 6" of something like Roxul Safe N Sound insulation (http://www.homedepot.com/p/Roxul-Safe-n ... /202531875) help to isolate the external noises? Thanks

We'd need to know a lot more about the situation to be able to say what is "enough" and what isn't. For example, we'd need to know just how loud those planes are, and if it is mostly high frequency noise, mid range noise, or low frequency noise. You didn't mention if your building is on the arrival path or the departure path for the airport: two different types of noise. So your first course of action should be to break out your sound level meter and actually measure the noise as a few different planes fly overhead. Measure both inside the building and also outside, so you can document how much isolation you are getting currently, from the existing structure. With that information in hand, it is then possible to design the isolation strategy for your room. That being said, just treating the ceiling by itself is not going to improve things much, if at all. The sound from those aircraft does not just come down through the ceiling. It also comes in through the walls, door, windows, HVAC system, and likely up through the floor as well. It is not possible to isolate a room acoustically by treating just one side of it. To illustrate how futile this is, I often use the analogy of someone deciding to build an aquarium for his living room, so he can look at the fishes. But he reasons "I only need to look through the front, so I'll just put glass on the front of the tank, and leave the other sides open".... That fish tank with glass on only one side will hold water just as well as your studio with isolation on only one side. Sound is like water in many aspects: it ignores the "hard" path and takes the "easy" path. If you isolate only your ceiling, then the sound will ignore that excellent isolation and simply go around it, taking all the other paths into the room. just like the water in the fish tank will ignore the glass front, and rush out through the other sides of the tank.

I've been researching isolation designs online and most of them suggest a 2 layer drywall ceiling filled in with insulation.

That's the basic concept, yes, but it has to be done correctly. Technically, that's called a "two leaf" ceiling, and it works on the basis if a principle in physics, called "Mass-Spring-Mass" or MSM. The idea is that the two "leaves" of drywall on either side are the "Mass" and the "Mass", and the air in the middle is the "spring". We don't normally consider air to be "springy", but for sound waves it sure is. So the concept is that the two leaves are separated by air only (plus fibrous insulation). That means that there cannot be any mechanical connections between the two leaves: each of them must be attached to its own individual frame, and the frames cannot touch. At best, there can be a special resilient connect between the two, provided that it is properly designed, but you cannot just nail drywall on either side of some studs, because the studs transmit all the sound from one side to the other. So, yes, if you can hang a proper suspended ceiling that is hung on acoustic resilient hangers, then that would work as an isolation ceiling. But a typical drop ceiling will not work, as the hangers are not isolated and there isn't enough mass in the ceiling tiles. Not even vaguely close. One thing you could do, is to take the existing ceiling (if there is any) so you can see the joists above, then attach proper acoustic "resilient channel" to those, and hang new drywall from that. Or even better, put RSIC isolation clips on the joists, then put ordinary hat channel on those clips, and hang the new drywall from that. You cannot use hat channel by itself: it has to be isolated with the RSIC clips. However, there are equations that tell you how much isolation you will get, and what frequency you will get it at, based on the materials you use, so you do need to use the right materials. The two key factors are the amount of mass on each leaf (in terms of surface density: how much does each square foot of the leaf weigh), and the depth of the air gap between the two leaves. The bigger the air gap, the better the isolation. The more mass on each leaf, the better the isolation. Big gaps and high mass will get you very good isolation down to very low frequencies. Small gaps and low mass will only get you isolation in high frequencies. And all of that assumes that you are treating not only the ceiling, but also the walls, windows, doors, HVAC, electrical system, and perhaps even the floor if it is an issue. So start by taking measurements with a sound level meter (set it to "C" weighting and "Slow" response), then report your numbers here, and also post a few photos of the building, both inside and out, as well as more info about the type of noise, and where you are located with respect to the airport. - Stuart - - Stuart -

Thank you Stuart for taking the time to respond to my post. I really appreciate it, and know that you all are very busy. Here are some additional details on the room: Dimensions: These are the dimensions of the room without any interior drywall. Length = 194” (16' 2") Width = 116" (9' 8") Height = Approximately 11' (The roof has an incline. Lowest part is probably 10 1/2 ft) Room Setup: The room is in the 2nd floor of a large warehouse space containing a few small and medium sized individual rooms used by visual artists and myself. The right side longer wall of the room is shared with another room used by a visual artist; on the other side of the left longer wall is the hallway and entrance door to the building; on the front short wall is a metal commercial entrance door to the room and hallway; in the back are 2 large single pane windows that lead to the exterior. Directly below is a carpenter who uses his space to build cabinets and furniture when not out in the field. Foot traffic in the hallway is very minimal during the weekdays, but can get somewhat heavy during the weekend evenings when events are held at a larger room at the end of the hallway. The "control" room is directly across the hallway (about 3-4 ft away). That room is double the space and am currently working on setting it up mixing. The building walls are brick, and the building itself surrounded by other warehouses. There is a train that passes by on the other side of the building. Noises from the train get through the ceiling every now and then, but not too bad. Noise Considerations: This room is definitely not ideal but what I can currently afford, so I'm just trying to make it work in some capacity. Here are the noise issues: 1.) Foot noises from the hallway 2.) Next door neighbor plays music and can be heard in the room, enough to create problems for recording. 3.) Carpenter below uses some saws and some of the machine sounds travel up. His ceiling is open, just board, joists and my hardwood floor above. I'm currently in talks with him to come up with a plan for isolating the section of his ceiling where my room is located. 4.) Environmental noises getting through the window. 5.) Airplane and rain noises on ceiling. Airport is 3 miles away. When air traffic gets redirected to our area due to weather (approx 1 or 2 nights per week), we are on the arrival route. I have not yet measured the dB level of the airplane noises but will measure them when possible. 6.) No HVAC system yet, but plan on installing a mini-split system in the near future. Currently, I am a bit saddened by the situation. So far, I have updated the room by doing the following, and unfortunately my efforts have done little to help the situation: 1.) Filled wall cavities between metal studs with Roxul Safe-N-Sound. From the inside of the room, I installed Isolation Clips on metal studs, and use furring channel with 2 layers of 5/8" drywall. Seal gaps with acoustic caulk and covered electrical outlets with putty. 2.) Created "doors" that cover window space, but can swing open from the center if needed. The "doors" are like walls that swing open - 1 layer of drywall, stud, safe n sound insulation, and 2 layers of 5/8" drywall. The plan now is to treat ceiling, seal door to the room and and treat ceiling below room. In any case, despite these efforts the results haven't seemed to help much. The window doors seemed to help block out the environmental noise coming in from the windows, but I can still hear the music from the adjacent room when the artist is in and noises from the hallway (talking, foot noises). I haven't yet sealed the door and I know some of the noise is getting in from there, traveling through the floor and ceiling. I have the option to add another layer of sheetrock to the other side of 3 of the walls since currently those sides only have 1 layer of 1/2" drywall, but I am thinking that won't help much. I would like to have the entire room be available to use as a live room so that I can track drums, etc. However, my thought now is that if this room has too many issues to deal with, I will just build a small booth inside the room and rent space at other studios when necessary. I wanted to avoid this because of the boxy sound of small booths, and cost for renting other studio spaces. Nonetheless, my idea for this booth to build it to 6' wide x 6' long and 8' tall. The base would be plywood and MLV on top of studs that sit on u-boat blocks, with acoustic insulation in between studs. Walls and ceiling would be studs filled with roxul 60 or 80, with 1 layer of 1/2" drywall on both sides. Booth would placed in a corner of the room, spaced away about 6 inches from the room wall. Please let me know if this is a bad idea, and should just focus on the room. Attached is a picture of the space before walls went up. This pic shows the window which has since been covered. I'll post a more recent pic shortly. The next pic is of the front wall before clips, channel and double walls went up. Any advice/feedback would be greatly appreciated. Thanks, Wil

Since my last post, I decided that it would be best to put a stand alone recording booth in the other room, the "control" room, instead of in this live room. I would like to keep this thread open as I still would like to come up with a good strategy for isolating the live room in the best way possible, but will take it in steps as budget permits. The idea for placing a recording booth in the other room has been posted in another thread to keep the discussions separate: viewtopic.php?f=3&t=18803 Thanks, Wil

I've been doing some research on the forum and it seems that building a booth is probably a bad idea, and it may be better for me to invest in isolating the live room as much as possible. I saw a post from someone who built a booth with 8ft ceiling and he was struggling with an extra boomy sound in all recordings. If I am wrong in this conclusion, please let me know. Thanks, Wil

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3.) Carpenter below uses some saws and some of the machine sounds travel up. His ceiling is open, just board, joists and my hardwood floor above. I'm currently in talks with him to come up with a plan for isolating the section of his ceiling where my room is located.

The best way to deal with that is to seal up that floor (his ceiling) from below, probably add more mass to it by using the "beefing up" technique, then install suitable insulation to fill the joist bays, put resilient channel across the joists (or better still, put RSIC clips on the joists and put hat channel in the clips), then hang two layers of 5/8" drywall from that. He'll have to do that across his entire ceiling, not just the part under your room. This is actually a key point to isolating your room in both directions (sound going in and sound coming out), for the entire building, not just for the carpenter's shop.

6.) No HVAC system yet, but plan on installing a mini-split system in the near future.

That's not HVAC: that's just H-AC! Ventilation is the key part of studio HVAC, and mini-split systems do not provide any. All they do is cool (and perhaps heat) the air in the room, but they do not provide ventilation. So you'll still need to look into that. HVAC is a huge and critical part of studio design, and is often forgotten or underestimated.

1.) Filled wall cavities between metal studs with Roxul Safe-N-Sound. From the inside of the room, I installed Isolation Clips on metal studs, and use furring channel with 2 layers of 5/8" drywall. Seal gaps with acoustic caulk and covered electrical outlets with putty.

That's a good start, but did you also seal up the far side of those walls before you started, and did you beef them up with additional mass?

2.) Created "doors" that cover window space, but can swing open from the center if needed. The "doors" are like walls that swing open - 1 layer of drywall, stud, safe n sound insulation, and 2 layers of 5/8" drywall.

Since you also have the actual glass in there too, you are creating a 3-leaf system like that, so your isolation for low frequencies will be poor. Take off the single layer of drywall on the side of the studs facing the glass, put it on top of the existing two layers of drywall on the other side of the studs, and you'll get a large improvement in isolation. However, you also need to make certain that the window itself is sealed absolutely air-tight: caulk all the edges, and if it is an operable window (one that opens) then open it, apply abundant caulk to all the operable surfaces, close it, screw it down tightly with good screws in several places, then apply more caulk all around the edges where the moving surfaces meet the fixed surfaces. If the glass is thin (less than 6mm) the replace it with thicker glass, preferable laminated, before you do the above. Finally, make sure that your swinging shutter has really good rubber seals all around the edges, at least two independent seals that mate against different surfaces, and that they seal completely, leaving no air gaps at all when, it is closed and locked in place.

The plan now is to treat ceiling, seal door to the room and and treat ceiling below room.

Start by making sure that your existing ceiling is only one leaf, not two. Once that is confirmed, you'll need to do to your ceiling the same as what I suggested for the carpenter's ceiling below you: seal that leaf, add more mass, then hang a new inner-leaf ceiling from some sort of decoupling system.

In any case, despite these efforts the results haven't seemed to help much.

Right. You wont get results until the entire shell is completed as a fully enclosed 2-leaf MSM system. Right now you have only done the walls, but not the floor or the ceiling, so the walls aren't actually doing much, because the sound is flanking around them and getting in through the parts that have not been done. You won't get the full isolation until you squirt in the last bit of acoustic caulk in the last gap, after all the rest is done.

noises from the hallway (talking, foot noises).

Do yourself a favor, and splash out some money to carpet that hallway. Lay a good thick underlay, and a good thick carpet. You'll likely score brownie points with your neighbors, and you'll make your own life a lot easier. That won't isolate your room any better, but it will kill impact noise from footfalls, and also damp voices to a certain extent. Solve the problem at the source, rather than trying to deal with it at the destination which is much harder and much more expensive...

I haven't yet sealed the door

:shock: Then that would explain why you aren't getting results yet! You are in the same situation as the guy who has a roof that leaks every time it rains, and he has done a lot of work waterproofing it and sealing gaps.... but he still hasn't replaced the four missing roof shingles, right in the middle of the roof, where all the water is getting in... 8)

I have the option to add another layer of sheetrock to the other side of 3 of the walls since currently those sides only have 1 layer of 1/2" drywall, but I am thinking that won't help much.

It certainly will help! If you have access to those walls, then how about taking off the drywall om those, putting RC on them, adding more insulation, then putting two layers of 5/8" drywall on there too, staggered joints, and carefully sealing it all air-tight! If you have access to all of that, then you are in the rare position of being able to fix things that many other studio builders in shared facilities cannot do, and desperately wish they could.

However, my thought now is that if this room has too many issues to deal with, I will just build a small booth inside the room and rent space at other studios when necessary.

It sounds to me like you are giving up before you finish the job. It seems like you are doing that because you aren't getting any results yet, even though you haven't finished yet. Just like the guy with the four missing shingles, getting disappointed because his roof still leaks even though he hasn't done the most important part yet... His roof is still gonna leak water until he puts in every last missing shingle, and your room is still gonna leak sound until you put in every last missing piece to complete the system. Perhaps another analogy: You are like the mechanic rebuilding a car engine, and getting disheartening because it wont start yet: you connect the battery and turn the key, and it spins nicely, but just won't start. So you decide to give up, and tell everyone it is pointless to carry on trying to make it work, and you aren't even going to bother putting in the spark plugs or connecting the fuel line, because if it wont start without those, then why would it start once they are in? ... Get the point?

Attached is a picture of the space before walls went up.

and what did you do about the big red sprinkler pipe, the gas pipe, and the heater? How did you isolate those? What did you do about that 8" vent pipe coming down through your ceiling and hanging there? What did you do about the electrical conduits, where they penetrate your outer-leaf walls?

I've been doing some research on the forum and it seems that building a booth is probably a bad idea,

:thu: Yup, very much so if you have the option to do a proper room in such a great space as you have, as shown in the photos and your description. Not many people get the chance to build a drum room wit an eleven foot ceiling... Most studio builders on this forum would seriously consider cutting a deal with the devil himself to get such a wonderful opportunity... :) - Stuart -

Thank so much for taking the time to provide feedback. Much appreciated. I'll continue to work on the room and will post updates. Sometimes air traffic is redirected to our area and descending planes fly right above our building. I ran a test to measure the amount of plane noise that gets in through the ceiling (and window), and I got between 65-70dB. Any advice on how best to isolate the ceiling from that? Best, Wil

Another affordable option is to use industrial grade acoustic blankets that are like like 2-4 cm thick. The main advantage of these is that you can quickly assemble as well as disassemble the whole thing at any time. You just hang them around the walls and that's it. You should try something like [SPAM LINK REMOVED BY MODERATOR]. They're usually used around construction sites, so they should block or at least muffle pretty much any sound. Apart from gunshots and explosions.

Another affordable option is to use industrial grade acoustic blankets that are like like 2-4 cm thick

I hope you are just kidding.... Or are you SERIOULSy suggesting that those blankets would be a good way of isolating a high quality recording studio? Did you even read your own link? It says: " Our sound attenuation blankets are lightweight, ...". Did you notice that? "lightweight"? Lightweight implies low mass: Low mass implies no isolation. The ONLY way you can stop sound effectively at a reasonable cost is with mass. Low mass = low isolation. It really is that simple. You can't bypass the laws of physics. I'm also wondering why you are posting on a thread that has been inactive for a year and a half!? Also, please read the forum rules for posting (click here). You seem to be missing something rather important... - Stuart -