Building a new Drum Room

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

  1. Jason Morris

    Jason Morris Active Member

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    Holy crap. 29db doesn’t seem attainable considering how quiet the room is and spl is saying 55-58. I can’t even imagine what 20 sounds like.

    If it’s the AC from the existing structure I’m probably going to have to live with it and do things different on the next one. :/ not giving up yet just not sure what I can feasibly do that doesn’t involve destroying the room and rebuilding from scratch.

    If you look at the video you can get an idea of where my mechanical room is. Basically there’s my drum room, a flight of stairs. And next to that is the mechanical room.. so it’s close.

    The anecdotal testing seems ok. The wife is thrilled with how much more quiet things are, but as expected she said she can still just barely hear the kick drum... but that it wouldn’t keep her awake or bother her as she watches tv.

    The sound of the drums inside the room.... insane. Holy cow. There is so much low end. Can barely hear the snare over the booming kick drum. Kick sounds like a canon, but not in a good way. Heh
     
  2. kmetal

    kmetal Kyle P. Gushue Distinguished Member

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    Hmmm. Is that where the ac unit and boiler are?

    Well thats encouraging. Its not too late to add another layer of drywall tho if theres any concern. The acoustics can be adjusted as you go, the isolation not so much.... Id think deeply about this.

    It would be totally weird if the room sounded good as is, id question your tastes, or call you the luckiest person on earth. Bass trapping will go a long way in your studio. Also the position of the kit can have an effect too. No worries till a bunch of treatment is up.

    Fyi, my cousins basement control room was about 11x14 without much bass trapping it sounded like there was a subwoofer on in certian spots. Part due to my bright idea on the ceilings added mass (face palm). He ended up moving before we did a full acoustic treatment. Room boom. Ugh.

    Your perseverance is comendable sir.
     
  3. Jason Morris

    Jason Morris Active Member

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    The AC unit is outside, another 15 feet away or so. You can certainly hear it running in the basement though.
    And that part of the basement is not below ground, so it's just framing/sheathing between the exiting finish basement/family room and the AC unit.
    We have a walkout basement.

    Yeah, we bought this huge house with 5 bedrooms and two kitchens, expecting to have a ton of people living here for a while. My oldest two just moved out, and my wife's oldest will be going off to college soon,.
    In another year it will be just she and I, and her youngest 50% of the time... in this 4800sq ft house.
    I don't think we will be here for more than a few more years.
    So yeah, this won't be my last studio.

    But I would still like to figure out why this is happening. If I can't fix it I at least want to know where I went wrong so I don't make the same mistake again.


    Oh you mentioned seeing something that I should tear apart and do over.. What was that?
     
  4. kmetal

    kmetal Kyle P. Gushue Distinguished Member

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    This might be the culprit. If so they have mounts you can use to help it, although it wont help if its airborne noise, as opposed to seeping thru the ac's concrete pad. The issue could be lines the are running from the unit, attached to the wall, and running thru the structure.

    Is the noise in the studio Only when the AC is on?

    My other thought is do you use any light dimmers in the studio or on general?

    You have a nice house man! You should see some of the dumps ive been looking at buying.

    Ya know, :) instead of moving you could turn your house into a gigantic multi room studio!

    The main thing that i questioned was why the studs for the new ceiling didnt get tucked between the bays of the the existing ones. Like rod pictures in the "independently framed ceiling" section.

    The other was why you had access with the video camera to the space between the two ceilings. It seems like there should be an outer leaf (wall) sealing that off floor to ceiling, in front of the studio wall. I could be missing something with both concerns.

    Overall everything generally looks good. And i meant to add that the excessive room boom is actually a good sign. It shows you've got massive, airtight walls, that are not letting anything vent out. All the air is trapped. Good isolation makes acoustics worse, hence the extensive room treatments required in well isolated rooms.
     
  5. Jason Morris

    Jason Morris Active Member

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    It is certainly worse. When the AC is OFF the SPL meter reads about 41-44 DB.
    For kicks I used Decibel Meter Pro (an iphone app) and it read 30db in that room. I am sure the iphone isnt totally acurate, but would it really be THAT off?
    maybe its just not picking up the low frequencies that the SPL meter does.
    Both the SPL meter and the app were set to C-weighting.

    No, I havenet installed lighting yet. its just a plug-in light right now.

    Ahh thanks man. The downside of it being a nice house is that it came with a large finished basement which the wife was adamant I could NOT destroy in order to build.
    That made things really complicated. I was relegated to one tiny unfinished portion of the basement.

    Ha! That would be nice. Maybe the next place.

    Oh! that ones easy!
    The inside-out method! when you do the inside out method you can still push the drywall up to like a half inch from the existing joists.
    It is true that the joists stick out farther, but they provide a place for me to put the mineral wool I will use as treatment.
    If you sketch out some joists on a piece of paper and then draw the sheathing beneath them you should see that tucking the "inner" joists between existing joists, or doing them below the sheathing (via inside-out) method works out to the same ceiling height, at least acoustically.

    THAT is because THAT portion was part of the finished basement that I was not allowed to dismantle. :/ what you saw was outside the drum room.

    Yeah. it seems I pretty air tight. But it also seems I did something wrong. While I was in there this morning with the SPL meter, my step kid was stomping around upstairs and I could totally hear him. And I do mean STOMPING. the kid is incapable of any other form of ambulation. But it's still pretty discouraging. I'm wondering if I compressed too much insulation in the ceiling.
     
  6. kmetal

    kmetal Kyle P. Gushue Distinguished Member

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    Well that proves part of the problem. 10db extra is a big thing. The question now is how the transmission is occuring.

    40db range is much more like it. If i recall the cave measured somwhere around 35db in the main room.

    Yes, the iphone is That off! I experienced the same thing when working as a consultant/sound manager at a waterfront performance spot. 12db difference between the iPhone, and two different spl meters, c weighting. Like you i suspect the defficincey in the low frequency pickup of the mic.

    Where the iphone is useful if for a spectrum analyzer. Perhaps not the most accurate, but for rough guesses its cool, far cheaper than a purpose built one.

    I would check with a spectrum app and see if the same frequencies peak next to the ac, in the house right near the ac, and in the studio. This can verify the ac issue and problem frequencies. I suspect 60hz. Even the limited iphone thing should shed some light on this.

    Worth noting is you could gain a couple db once the internal insulation is installed.

    Also, the stc ratings are frequency dependent. So at 1k a wall blocking 55db is gonna block like 20db at 100hz. Roughly speaking. i dont have my chart around.


    So you know what to look for next time eh?

    Phew.

    If the studio leaf, is not fully enclosed by the outer leaf, this could be the crux of the whole thing. With the AC adding to the problem.

    Wondering if that opening isnt the issue. If the studio isn't a room in a room, then the isolation would be significantly compromised.

    The other thing could be any connection physically between the existing structure and studio. Does the silencer box or anything else, wires, pipes, ect connect the two rooms?

    Have you measured the spl in the studio with drums playing, and 3 feet outside the door with the drums playing?
     
  7. Jason Morris

    Jason Morris Active Member

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    It is fully enclosed, but its hard to describe how we did it. But being a glutton for punishment, I will try...

    The basement was almost fully finished. There was a small space that was NOT finished. That was the area I got to use for my drum room.
    as you walked from the finished room into the unfinished room and turned around to see the studs, you could see the ceiling of the finished room was soffited down in that area.
    When I was building my silencers, I stowed one in that soffited area (which you saw in the video).
    THEN when it was in place, we build a small wall which was placed on TOP of the existing wall, to cover the soffited area, and we sealed it off really well.
    That completed the "outer leaf".
    THEN we built the inner leaf of the drum room wall.
    Hopefully that makes sense.


    EVERYTHING goes thru the existing ceiling joists of that room. water pipes, wires, and a couple of HVAC lines feeding the dining room above.
    however, we were very careful not to allow any framing or sheathing from the inner leaf to touch those joists.
    The only thing that could feasibly be touching from one leaf to the other is insulation.

    Not yet. I'm waiting for my buddy to come over and help out with that. I tried doing it myself with the SPL meter set to "hold" which grabs the highest peak and displays that.
    That was very depressing.


    So, there IS one more thing. I may need to build one more small wall in the hallway adjacent to the drum room, towards the other side of the room..
    ugh. Im going to make another video to show you. too hard to explain..




    Also.. wow.. you can TOTALLY hear the AC unit as Im walking thru the finished basement.
     
  8. Jason Morris

    Jason Morris Active Member

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    So, i did what you (brilliantly) suggested and used the RTA app on my iphone, which is part of AudioTools...

    it looks like my problem frequency is actually 32hz. Thats what I am hearing in the drum room.
    and my AC unit is also crazy loud.

    Im uploading a couple screenshots from my iphone.
    One is taken right next to the AC unit.
    Another from inside the house on the other side of the AC unit, and a third from inside the studio.

    In the last pic (studio)You will see something at 125 and 250 registering. that is hand noise from me fumbling around taking the screenshot.
    When im just holding it only 32 and 60 are registering at all.
     

    Attached Files:

  9. Jason Morris

    Jason Morris Active Member

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    Oops look at that. I figured out how to use the pause button on the app to get a more accurate screenshot..
    Attached is what the RTA of the drum room looks like right now. IMG_3368.png
     
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  10. kmetal

    kmetal Kyle P. Gushue Distinguished Member

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    As long as its sealed your good. Does each outer leaf have the same mass?

    What type of insulation? Is it like barely touching or packed in? If its packed tightly it could count as a hard physical connection.

    Rod specs 25% compression for the mineral wool fire safing that touches both the isolation wall and the existing ceiling.

    So the ac is without a doubt contributing to the cause or is the entire cause. 60hz and 30hz, the octave below are where these machines run.

    I tend to think its airborne noise bleeding right thru all the walls, and/or possibly some connected pipes shaking the existing structure.

    It could be the unit itself shaking things, but since its on an earth dampened concrete pad, thats a good insulator. Does the house walls or foundation touch the ac pad? If not how close is it?

    Gonna watch the vid asap.

    From the pics your getting about 40db of isolation via all the walls which is a good amount at those frequencies.

    Ran a test tone at 60hz in the studio, and got similar isolation level, then the problem would likely be a air borne. If you got more isolation with the test tone, that seems to say that some physical connection is bypassing the walls.

    Im not a complete acoustical expert, so im trying to use what i know and suss things out.

    This may be a case where some of the big dogs should be called. Im not sure if Andre Avare is still an active member here. Might be worth tagging him into the thread.

    If you test the spl right outside the studio and inside, the difference should be what youd expect from the walls like that say 30db or so less inside the studio. If it isnt then that also seems to point to a flanking path shortimg out the walls.
     
  11. Jason Morris

    Jason Morris Active Member

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    Well, no. Three of the outer walls are 4" concrete. Everywhere else I beefed the sheathing up with 2 additional layers of 5/8" drywall.

    Pinky fluffy insulation. its not packed in. I tried to compress no more than 20%
     
  12. kmetal

    kmetal Kyle P. Gushue Distinguished Member

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    Ok cool so the wall mass is good, and sealed.

    Im thinking there should be a 1" airspace between the studio wall/insulation, and the outer leaves. Are the concrete walls the only walls which are "connected" by the insulation.

    I know limp mineral wool doesnt effectively transmit vibration, according to the book and rods drawings. I am not sure if the same holds true for pink fluffy.

    When you added mass, were the stairwell, and the hall area leading to the garage hall (the right hand wall when walkimg toward garage hall) areas you added mass to? Are those the outer leaves of the studio wall?

    Im thinking you may be correct about that green section of wall needing an outer leaf. Its a bit difficult to picture in my head. It seems to me that the garage hall is functioning as the outer leaf presently, and if so would need to be massed up if the wall section wasnt built.

    The upside is that little garage hall is a perfect echo chamber as is! A Great companion to the nice tight drum sound in the booth. Drool. Id certainly run a couple mic and speaker cables out there.

    Love, love, love, gretch kits. The most astounding snare i ever played was a gretch at a music shop. Im not a drummer, but ive had a couple beater kits over the years. The sound just lept off this snare, you barely had to touch it.
     
  13. kmetal

    kmetal Kyle P. Gushue Distinguished Member

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    Since the AC is a nuisance anyway, it might be worth thinking about some double deflection neoprene pads for it to rest on, and some (flex) isolation connectors to break the coupling between the house an ac unit.

    An ac company, or industrial supply co, might be able to help recconend some products. If i remember correctly mason industries website had tons of these types of things.

    I wouldnt do anything until i was sure, but it might be worth considering.

    Also, maybe there is a control on the ac unit that can make it run slower or quieter. Probably worth a call to the maker or installer.
     
  14. Jason Morris

    Jason Morris Active Member

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    The AC unit is pretty old. like 20 years old.
    My cousin is an HVAC guy, so I can get a new unit for a pretty reasonable cost, but that is an expense that will have to wait. We are installing another AC unit along with a furnace up in the attic to cool the upstairs, as that old unit outside cant keep up. Its always like 10 degrees warmer on the upper level as it is on the main floor of the house.

    The upside, is that I am planning to take a leg off the new AC/furnace system, coming down that hole I pointed out in the video and feeding that into the studio via another silencer.
    Going to use a motorized damper to control it.
    Hopefully THAT will go in next month. Maybe the following year I can think about replacing the ancient AC unit that is causing me so much trouble right now.

    :/
     
  15. Jason Morris

    Jason Morris Active Member

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    I beefed up the wall of the stairwell going from the basement up to the main floor.. That first one I pointed out between the mechanical room and my studio.
    The door leading out to the garage.. that echo chamber area... nothing was beefed up there.

    Yeah. Nothing is beefed up in that area, so I think building another wall there is going to be the task for us this wed.

    yeah, it would be, except that it's isolated away from the drum room! The green wall seaparates that space from the studio.
    Incidentally, that green wall is where my second set of silencers and the ventilation/hvac is going to come INTO the studio.
     
  16. kmetal

    kmetal Kyle P. Gushue Distinguished Member

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    Does the wall in the stairwell have added mass floor to ceiling, or did it trace the steps? In the book it addresses maintaing isolation when a stairwell is involved.

    Id be very careful to make sure the new units are on isolation pads.

    Id also make sure the unit has the capacity for the extra studio space, and the oversized ducting. In short id make sure the pro knows what you intend to do, and the specialized studio requirement details to keep it quiet.

    Last thing you need is double the rumble.

    The age old technique is to just have a speaker in the echo room, send the drums thru it, and record it with a mic. You can do this in realtime, or after the tracks are recorded.

    If you're planning on a hole in that wall anyway, its probably worth a couple feet of cable. Redco makes xlr and 1/4" jack plates that fit in standard electrical boxes. Little bit of cable and a couple boxes would go a long way. You dont even need the boxes.
     
  17. Jason Morris

    Jason Morris Active Member

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    Floor to ceiling.

    I grabbed 4 bags of mineral wool, and propped them in the corners of the room. Crazy how effective that stuff is.

    I couldn't resist and threw some mics up to see how things were sounding with just a little bit of mineral wool on the walls and 4 unopened bags propped up in the corners.

     

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  18. kmetal

    kmetal Kyle P. Gushue Distinguished Member

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    Hey man, thats encouraging sonically! I think the room is gonna turn out well. No nasty rings or boxyness and its barely treated. Well done.
     
  19. Jason Morris

    Jason Morris Active Member

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    So, I have a boat load of mineral wool with specs as seen in the attached screenshot.
    I am planning on doing corner traps in pretty much every corner I can.
    I measured out for the soffit traps you mentioned, Kyle.. I'm just not sure I can bring myself to do that. They would hang out so far into the room as to make it unpleasant to be in there.
    I think I'm going to have to go with either straddles or superchunks in each corner, including the wall to ceiling corners. I'm leaning towards superchunks. I know they are more costly than a straddle type corner trap, but I have a lot of the mineral wool already, and the stuff I am using is easily available to me, so I don't mind the expense.

    So here is what I am wondering..

    Considering my 8' ceilings (which are still considered 'too low' for good drum sounds) should I cover the entire ceiling with mineral wool? If so, should I then cover that with plastic sheeting to recover some of the mids and highs?
    Floor is going to remain reflective of course.

    I was considering doing a 'wiggly wall' as I have come to call it (sorta like in the picture attached.. that's not my photo but its a design I'm planning to copy). That wall would be my Helmholtz resonator.
    The back and side walls I was planning to cover in mineral wool, and again cover THAT with plastic sheeting, cutting strips out so that it wouldn't act as a vapor barrier.

    My concern is that as a drummer I don't want the room TOO dead. But I also wonder if "totally dead" is the best option for a room as small as mine.

    would spending time creating REW files be worthwhile in a live room? or is that more useful for control rooms?

    Does anyone have any thoughts?
     

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  20. pcrecord

    pcrecord Quality recording seeker ! Distinguished Member

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    I do have a too small drum room. It ended up near completly dead and I learned to work with it over the years.
    I pretty good at faking it now with room simulators or plain reverbs.
    I do have a hardware reverb for realtime mixing of my headphone mixes.
    When ever I go play, I put on my headphones and get a feeling of a bigger room...
    We'd all want the biggest room but get to work with what we have.
    I'm sure you make yourself a good recipe that fits your needs ;)
     
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