Building a new Drum Room

Discussion in 'Acoustics (Live Room, ISO Booths)' started by Jason Morris, Mar 19, 2018.

  1. kmetal

    kmetal Kyle P. Gushue Distinguished Member

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    Doors are the most difficult to get done right imho. They always take some finesse.

    Tricks ive found-

    Bevel the door jamb so the type K fits snug.

    Staple the rubber to the jamb before installing the jamb.

    To get the rubber stapled straight, dry fit it in, while laying in the floor and table. Use another 1x board resting up against the rubber. This sandwiches the rubber in straight. Then you dont have to stretch it or warp it.

    Use screws to install the jambs, this way you can partiallly screw them in, as your making adjustments and checking the door close for smoothness and seal.

    Use a wide cabinet clamp to bend the jamb if needed. For instance the middle of the jamb isnt sealing up right. Leave top and bottom screwed in half way, then use the clamp to bend the middle, screw in the middle.

    You may have to rip some width off the jambs so they are all even..

    Use a flashlight and have someone run it around the seal, while checking it in the dark from the other side. Or leave the lights one side of the door, check the other side in the dark.

    I also found it helpful to leave the door frame board with extra slack, then mount the hinges on door and frame, make sure it fits, then cut the frame board to size. This alleviates the need to measure the hinges super accurate relative to the top and bottom.

    Best of luck.
     
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  2. Jason Morris

    Jason Morris Active Member

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    Just dropping a line to reiterate that I HATE doing these doors/seals.
    I got the first set of seals on the two doors.
    things don't seem to be working as well as I would like them to though.

    I have done the flashlight (in my case a work light) trick.. I don't see any light around the seals.. EXCEPT the corners.

    I have not figured out a good way to seal up the corners really well.. where one seal butts up against another there is always a bit of a gap.
    If they overlap, the door doesn't close right.

    Any tricks for getting the corners right?

    also, how tight should the door be compressing into the seals?
    The doors are only just laying across the trunk rubber. the trunk rubber is too dense to compress much from just the weight of the door and closer.
    I ahve not placed the second set of seals, but right now the doors do not seem to be performing very well.
    I know things are not "done" yet, but I did some preliminary testing and was pretty disappointed.

    One of the challenges in studio construction seems to be that you can't really test the isolation until ALL the components are in place.

    :/
     
  3. kmetal

    kmetal Kyle P. Gushue Distinguished Member

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    Doors are the worst. The upside is once set correctly, they stay put for quite some time. It took me until door #5 until i could install them methodically, and less painfully. Still they take trial and error or just plain good luck.

    I think part of the reason for the redundant seals is the likelyhood of imperfection in one seal.

    I cut the corners at 45 degree angles. When the door shuts the corners compress into each other and create the seal.

    You could also do this with a butt joint, where the seal corners meet at a right angle. You cut one seal straight to meet up against the door jamb, and you the the other seal so its contour is meets up with the other seal flush.

    Difficult to describe. I can try again if this wasnt clear. If my life was not in shambles id have the pics available of the seal details.

    I also used caulking in the seal corners, to verify a continuous seal. Non-hardening silicone, or butyl caulking only. No acryllic.

    Either way, you want the seals to make slight contact with each other at the corners. Not enough to bunch up too much, but enough so there is no gap.

    Also the seals might be fine, you may just need to bend the door stop into place so it contacts the door. Do this with a cabinet clamp. Its why i use screws for the jambs. The invetible trial and error.

    Just enough to make contact. "A little bit". Maybe a 1/16 to 1/8th inch. More is fine as long as the door shuts. Prime goal is full contact.

    I will mention, i ordered type k on two different occasions, one was quite squishy and easier to work with, than the firmer one. They were both type k, but not identical.

    When i set the doors, i do it so a gentle push on the open door swings the door shut and lactched. The first two i did require a bit more effort and youve got to pull them shut with some force. Not convenient, but they do seal.

    Yes sir. This is the reasoning behind using lab tested assemblies.

    Its difficult for people who haven't suffered thru a build like you have, to understand the studio room a complete system, like a car or anything else. It only works properly in whole.

    You may need a second set of seals. These can be standard ribbed weatherstrip, type k, or magnetic weatherstrip. The magnetic is cool because it seals even if the door doesn't shut perfectly agaisnt the type k, its got flex and give, like the weatherstrip on a refrigerator. Ive not used the magnetic stuff yet, but its in rods book for good reason.

    Is the rubber installed with the thinner side attached to the jamb?

    Pics could help me verify what the issues are.
     
  4. Jason Morris

    Jason Morris Active Member

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    I am attaching some pics of where I am at with the seals. I have removed and reinstalled them numerous times. I'm about to tack in the last set of stops now.
    Between both sets of seals, things seem to be sealed up. I can't see any light.
    In fact, I daresay that when the light is off, it is the darkest room I have ever been in in my life.
    I'm still not 100% wild about the doors though. I may have to run with them for now and rip/replace the seals at a later date.
    I probably have 8-10 hours of fiddling into these seals right now. :/

    Also, I still have the door/seals to do for access to the water main. That is the last link in the isolation game.
    I have done a little testing, despite the gaping hole. I sure do hope there is a dramatic difference once that hole has a door in it.
    My testing has shown pretty terrible low-frequency isolation. I guess its to be expected when there is a 2'x3' hole in one wall.
     

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  5. Jason Morris

    Jason Morris Active Member

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    So, as I mentioned, I did some testing, even though that access hatch for the water main is not done, and I found the results pretty disappointing.
    Now I am wracking my brain trying to think of things I may have done wrong/poorly along the way.
    The only thing I did that I am a little worried about is this: For the inside out wall assembly, it still calls for insulation between the inner and outer leaf (in that 4" air gap space).
    All of my insulation had kraft paper on it, and rather than ripping it off, I applied the insulation kraft-paper side to the drywall with spray adhesive and a few staples at the very top in keep the insulation in place.

    I know that kraft paper is generally recommended to be removed, but I thought I read that it can be applied with the paper facing the drywall side to avoid creating a mini .3rd leaf.
    I am hoping this is not the thing short-circuiting my whole assembly. Not sure what I could do about it at this point actually.
     
  6. kmetal

    kmetal Kyle P. Gushue Distinguished Member

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    The seals look good to me overall. The one concern i have is on pic #3327, the bottom left section. The seals dont appear to meet. That is an issue.

    You can also put silicone (non hardening) caulking at any seems in the wood work. I caulk everything that is a seem, including the finish moulding. You can use is at corner junctions of the seals too. I use clear caulking for all this.

    Sounds about right. Ive put 35 hours into a single door before. At least you've only got to get it right once.

    Im not completely well versed in inside out methods. I have left the kraft paper in wall frames in any builds ive done, installed in a standard fashion. Its there as a vapour barrier, and i think possibly a fire code thing too. The kraft paper itself will not make or break an assembly.

    That said, my concern is the non-standard installation, mainly the use of the adhesive. Adhesives can affect the vibration and transmission characteristics negatively. Its why we dont use caulking between drywall layers, which would simplify installation. It restricts the sheets' ability to to vibrate independently of each other, forming a rigid connection between the two. Its what makes green glue special, it doesnt do that.

    That said, i wouldn't expect the kraft paper or installation method to be a significant culprit based on what i know. I could be wrong, and i reccomend you check with Stewart, or other pro well versed in inside out methods.

    Areas of concern for me-

    The seal integrity between the door jamb, and opening in the wall. Rod details it in the book. I spent alot of effort with the backer rod and caulking sealing the jamb. I remember using quite a few tubes of silicone to seal the gap.

    The exposed joists in the inside out method. I expressed concern about this a while back. Not being an expert in inside out, i was concerned the the joists themselves should be "wrapped" in drywal and seemed/sealed 'properly'. My concern is credited to the section in the book where Rod states the "joists themselves are the weak point in isolation" (not a verbatim quote, doing it from memory) when describing the existing ceiling with mass added to the bays. This to my mind and eyes resembles inside out construction. Now since the joists arent touching the existing assembly in your case, then it comes down to if the joists are air tight, and as massive as the drywall. I would inspect for air gaps.

    ----

    Also, did you add mass to the door? Does the mass = the wall mass?

    Also, you may need to add a latch to the door to keep it firmly shut. The door closure unit is designed primarily to close the door at a slow, safe rate, to avoid accidents. (My uncle severed his finger tips because of an unsafe massive steel commercial door at his job.) The closure may or may not also keep the door shut firmly. Its a safety precaution first and foremost.

    A deadbolt, or a ball and socket catch can be used to keep the door shut. Ball and socket is something i discovered during the Normandy build. I previously used standard knobs or deadbolts.

    https://www.lowes.com/pl/Ball-catches-Door-hardware-Hardware/4294395585

    ------

    I would not be surprised to see a healthy increase in isolation when the water meter hole is plugged up. Therefore i wouldnt get too worried just yet.

    I would still verify all possible gaps are sealed, and that the kraft paper is negligible.

    Doors suck.
     
  7. Jason Morris

    Jason Morris Active Member

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    Yeah you are correct. I will caulk the. corners up and see if that improves things. IU am trying to view these as "Doors 1.0".. I may have to break down and rip and replace the seals at some point.
    Maybe doors 2.0 will be better.

    Yeah when I was complaining to my lovely wife about the 8-10 hours I put into these seals she laughed and said it was about twice that. I did the math and she was right. (as usual)

    That is a pretty big relief honestly. I really tried to stick. to what I have read are best practices, but when it came time to add the insulation I was kinda scratching my head. My buddy and I came up with this method and I did a quick search to see if Kraft paper touching. the drywall was a problem. I thought I remembered someone saying basically the same thing you said, but honestly I have so many tidbits of knowledge swirling around in my head sometimes I lose track of what I really know and what I only THINK I know.

    I'm not sure what you mean about this one.. I caulked the gaps between each drywall layer, as I thought I had read I should do in Rod's book? Do you mean we don't glue one layer of drywall to another with construction adhesive? Cause that I did NOT do. I DID use green glue. Not sure that was worth the expense. Probably won't use it again in the future.


    Yeah, I know you had mentioned that, and I don't doubt your knowledge, and greatly appreciate the help you have given me. But I am also pretty confident in Stewart & Johns knowledge level, and I know Stewart does pretty much all of his builds that way. I am adding a pic of the ceiling joists/modules so you can see what I have going on.

    I have TWO standard 1 1/2 solid core door slabs with 3/4" MDF green-glued and screwed to it.

    Thats a relief. I know it isn't really possible to test this stuff accurately until its done, but when you have been working at it for like a. year and a half, its. hard to resist sometimes. :D

    On. another note, I know you mentioned your life being in turmoil right now. I hope its nothing serious, and I hope things calm down soon for you.
    Thanks again for the encouragement and guidance as I go thru this build!
     

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  8. kmetal

    kmetal Kyle P. Gushue Distinguished Member

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    You could also try and attach a little piece of type k, if the gap is big enough.

    Yeah thats what i meant. Glad you didn't do it.

    Me too, while i can hang in a conversation with anyone at this point, i wouldnt put myself up at their level. Especially in the inside out dept. I trust their words. I have seen very knowledgeable people make mistakes, or unknowingly spread mis information, but nobody is perfect. By know john and stewart have their methods down to a science.

    I wish that there was some lab data on the inside out method, for reference.

    Your modules look very well sealed.

    Sounds well done. I haven't calculated the mass vs your walls, but thats a hefty door either way.

    Oh for sure. I remember having an ipod hooked directly to the power amp and speakers in the empty control room at Normandy. Also i remember recording acoustic guitar in the untreated wave cave live room and the feeling of joy.

    Thanks for the kind wishes. Starting from scratch is difficult, but there is some good stuff brewing over the horizon.

    Glad i can be useful, i always respect anyone willing to do it properly. Cheers man!
     
  9. Jason Morris

    Jason Morris Active Member

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    I'm not trying to belabor the point, but while I was searching for information about the best type of insulation to use on the inside of my studio, I came across this post by Stewart:

    " Even though wood is a bit less dense than drywall, studs are much thicker, and serve just fine to keep the surface density of the wall high enough. At an inch and a half thick, a stud is about the same surface density as two layers of 5/8" drywall."

    http://www.johnlsayers.com/phpBB2/viewtopic.php?f=1&t=19817
     
  10. kmetal

    kmetal Kyle P. Gushue Distinguished Member

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    This is excellent info. Im glad you posted it.
     
  11. Jason Morris

    Jason Morris Active Member

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    OK! I got my hatch built.
    I also am like 99% sure I know where I am losing low end isolation.

    It's coming from my silencer box. I have one set of silencers (for exhaust) built and installed and very well sealed up.
    They were made out of two layers of 5/8 plywood and have i think 4 baffles inside them.
    When the AC runs in the house I can hear the very low frequency rumble in my room, and it is clearly louder coming from the silencer box.

    I have a silencer on the inner leaf connected to a silencer on the outer leaf with sorbothane rubber.

    Maybe a video would be a better way of explaining what I have going on..
    As an added bonus you get to hear my weird voice!

     
  12. Jason Morris

    Jason Morris Active Member

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    Oh, I found some photos that might be helpful as well...

    One is the silencer being built, the other is the silencer mounted in the wall before it was sealed up with drywall.


    Edit: just realized the photo of the silencer being built is the OUTER leaf silencer, while the mounted silencer is the INNER leaf silencer.
     

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  13. kmetal

    kmetal Kyle P. Gushue Distinguished Member

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    Let me preface that hvac is the area of least knowledge for me. I know the basics, but have not installed a ducted system ever. Ive done thru wall ac's, mini split systems. The only ducted system i dealt with was already installed at Normandy, and there wasn't much to do with it.

    I have a couple guesses. I think its either structural coupling, or the silencer is acting as a helmholtz resonator wisking air at a certian frequency. It could also be that the air flow is too fast, ideally its big ducts, and slow moving air. First 5,000 questions. I may also add that this next week or two is looking hectic for me so i will do my best to check in as often as possible. It could also be bleed if there is not double walls on the walls which dont have the concrete behind it.

    How did you test the sound?

    What frequency is the low noise, is it a fairly sharp peak or a wide one?

    What type of hvac is that?

    What type of ducting, hard or soft?

    What size is the ducting?

    What is the ducting attached to, and how?

    Is the ducting and other hvac all attach to existing structure or new room?

    Is the low end from the the hvac or is it bleed from drums out of the room?

    Is the hvac connected to the rest of the house or studio only?

    Is there a double wall on the door side?

    In the second picture, is the silencer mounted to the existing structure or new room?

    At the point of the inlet, the wall penetration, is the new wall touching the inlet?

    What is making you think the issue is silencer box related?

    Is there any known low frequency issues related to inside out methods?
     
  14. kmetal

    kmetal Kyle P. Gushue Distinguished Member

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    Did any pro help with the design and implementation of the silencer and ducting and hvac blower or overall design of the system.

    I Also saw a couple of structural things, which could be improved on, but are unrelated to the hvac. Im not sure if you care to hear them as they would require some disassembly and re assembly to fix. You would likely be able to re-use the materials.
     
  15. Jason Morris

    Jason Morris Active Member

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    mostly with my ears.. I can hear a very low frequency rumble in the room when the house's AC is running.
    Using the SPL meter in there (c-weighted, slow) I see the ambient noise level is like 56-58DB.
    Sticking my ear up to the silencer vent I, it seems the rumbling is louder coming from there.
    Thats about as scientific as I got.

    Im not sure how to answer that. Its pretty low frequency. If I play my drums without earplugs in for a little while the noise magically vanishes! :D

    its not really HVAC. The sinecers is just connected to a Fantech ERV unit. The unit isnt even turned on at this point. Its the HVAC sound for the REST of the house spilling into the room.

    Flex duct going into the silencer.

    The Fantech is 4" ouputs, so 4" duct going into the silencers, and then the cross-section within the silencer expands in order to slow down the air velocity.
    But like I said, the fantech isnt even running at this point.

    ?? the silencer, via a 4" take-off.

    The "inner leaf" silencer is screwed to the concrete wall, and does not touch the inner leaf. The OUTTER leaf silencer does just sit in the rafters of the existing structure.
    It was a compromise I had to work around.

    Its just low end rumble from the AC cooling the rest of the house. But doesnt bode well for my low end isolation.

    Yes.

    existing structure. The concrete wall of the basement. It doesnt touch the inner leaf.

    no.
     
  16. Jason Morris

    Jason Morris Active Member

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    Sure, I'd be open to hearing them.
     
  17. kmetal

    kmetal Kyle P. Gushue Distinguished Member

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    Im a bit confused as to the hvac system generaly for the studio? Is it just the air exhange? What are you using for heat and cooling?

    Im also confused as to how you still have acess above the studio ceiling. If there is concrete behind two walls (assuming the studio is in the basement corner), and the other two walls have the inner studio leaf, and the outer leaf (which should be connected to the basement concrete floor, and house joists). How is there acess? The ceiling of the studio (and walls) should be encapsulated completely by the concrete and outer leaf.

    Heres a couple tests. You can plug the silencer opening with a couple scrap peices of drywall an see if the noise goes away.

    If you have a loud speaker, like a PA or loud stereo, you can play some test tones outside the room loudly and see what frequency is loudest bleeding into the room. You can do this with the hole plugged and not plugged, which will tell you what the hole could let in.

    The main structural thing im curious about is why the ceiling joists are running under the house joists instead of running in between them. It seems to sacrifice a few inches. I might be missing something here.



    Thats a bit loud. Is the houses hvac connected in any way to the studio? Oris it just an ERV unit running in and out of the room.

    Thru ducting, or possibly a physical connection of some sort?

    How is the flex duct mounted?

    So neither silencer is physically touching the studio framing or walls? I consider the existing structure "the outer leaf"
     
  18. Jason Morris

    Jason Morris Active Member

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    Out of curiosity, what would one expect?
    I will say that the room is exceptionally quiet. I'm pretty sure I can hear my hair growing.
    But maybe its just really good at blocking high and mid-range frequencies, and xomething fell apart for me at the lowest end of the frequency spectrum.

    Not yet. I nfact, I do not even have the other set of silencers cut in yet. Only the "exhaust" silencers are built and going thru the wall.
    I wanted to test things before I cut another hole in the wall and tackled another set of silencers. I have easy access to the other side of the wall, so saving that portion till later was feasible for me.

    I AM planning on installing a new HVAC system to service the top floor, and I think I am going to use a line off that (along with a motorized damper) to get conditioned air into the room.
    But like I said, I havent got that far yet.

    Im not sure. Its such a low frequency that it seems to be coming from everywhere, but it does seem to be louder coming from the vent of my silencer.

    No. neither silencer is touching the walls of my drum room. One of the silencers IS touching the rafter of the office area adjacent to the drum room, but it is NOT making ANY contact at all with the drum room.
    It IS making contact with the other silencer via 3/4" thick neoprene rubber.

    I used this to build a coupler which joins the two silencer boxes between the leaves:

    https://www.amazon.com/gp/product/B01CT6TIW8/?tag=r06fa-20

    Again, the silencers are not touching the inner walls of my drum room. I left a gap around the permiter of the silencer where it penetrated the wall and filled it in with backer rod and caulk.
     
  19. Jason Morris

    Jason Morris Active Member

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    OK. I just covered the silencer vent with some mineral wool and a 3/4" piece of MDF.
    The low frequency noise didnt go away, which makes me wonder if it isnt coming in thru the ductwork across the ceiling and in that soffit we built.
    And maybe that low frequency spillage is amplified due to the natural room nodes?
    I dunno. this is voodoo to me.

    All i really know if "make it dense, leave a 4" airgap, insulation is a damper, and caulk the hell out of it" :/
     
  20. kmetal

    kmetal Kyle P. Gushue Distinguished Member

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    20 dba is the target ambeint noise level for a studio.

    Chart-

    http://www.sengpielaudio.com/TableOfSoundPressureLevels.htm

    PDF-

    http://tech.ebu.ch/docs/tech/tech3276.pdf


    Its important to use large, lined ducting, and incorperate some right angle bends in the duct to minimize bleed. The damper will control the temp.

    Im guessing its mechanical noise. Does it only happen when the AC is on? Where is the AC unit located?

    Its a possibility. Anything that would travel along the ducting should not penetrate those walls. It would just eminate from the source, thru the air space or even walls.

    Im wondering that its a mechanical vibration traveling along the existing house sturcture and bleeding into the studio. If it was rigid ducting not useing iso mounts for it could be an issue.

    What about your water heater/boiler? That could be a culprit.

    It could be inherent in the inside out method. A series of small panels resonates at a higher frequency than larger ones, just like a small vs large cymbal. Not being super well versed in the method i cant say for sure. It seems it would be discussed if it were a common issue. Id double check at Sayers site. Id also love to see test data on the method.

    Rods book states the ceiling assembly in he describes has a resonance of like 19hz. If you have similar mass i would expect the same result.

    This is where im thinking its mechanical noise, or the inside out method.

    At the wave cave, there was a regular thru wall AC unit on the rear wall of the control room. The first builder built a booth in the control room, with steel studs, and resillient channel on both sides. The booth walls were connected to the inner control room wall, and both control room and booth walls were built on top of the same wood framed floor, resting on the concrete. He didnt fill the deck with sand. All the walls (booth and control room) were connected to the studios ceiling which is second floors floor made of planks, in an old mill.

    When the AC is on the U87 mic would pick up a low frequency rumble. This didnt occur when drums or the dehumidifier were going in the main room, or at all in the other booths (built properly).

    The vibration of the AC was traveling down the CR wall, and thru the floor into the booth. Bypasing the booths walls.

    Im suspecting something similar in your case.
     
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