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home theater acoustics and design

Discussion in 'Room Acoustics / Studio Design' started by kmetal, Sep 12, 2014.

  1. kmetal

    kmetal Kyle P. Gushue Well-Known Member

    Hey everyone, my buddy ask to help him w his home theater. So I figured I'd add a thread to keep all the construction and acoustics related to it in one spot. This isn't my project so I don't have any control other than the power of suggestion, but I thought this would be a great opportunity to learn some stuff as this process goes on, and also have a documentation of some of the inevitable hangups, so maybe somebody else in a similar circumstance could have a resource. This is just at the brainstorming phase overall. Anyway here's the basics:

    We're in the planning phase of a basement home theater/kitchenette,in a 7'2x15x30 and 7'2x12x20' (rough) area. It's a walk in basement, 2x8 12"oc, 2x4 walls, and foundation in some areas.

    This is the 'front'.


    That is the 'rear' walkout part of the basement image.jpg

    That is looking a little left from the rear door.

    The plumbing you see is for the existing bathroom/shower, that will stay.

    Ill attach some shots of the place so you can get a better feel. Anyway.

    The ISO requirements/expectations would be met if a person could comfortably go down with an acoustic guitar and sing along at an average folk style volume. When 5 cizek speakers and 2 15" custom (it'll be a first for me) subs, powered by haflers, its gonna just get loud down there when the audio video mayhem happens, and it'd be absolutely ridiculous to have expectations of doing much against that, and with around 10k budget for the raw materials, it's gonna add up fast, although the existing physical space limitations, are really the determining factor in the overall design. So the overall idea is to just make a nice comfortable place that offers privacy, and as much isolation as possible, given the existing conditions.

    Since there's a fireplace (see pic) that runs right upstairs, and a fairly low ceiling height, it's seeming that the best option is basically similar to the example build in rods book, with a channel system for the ceiling, and double walls, stains concrete floor/area rugs. My thought was to use RSIC-1 clips and hat channel, in place of the RC channel as described in the book (ed1). After a lot of thought, that seems like the best compromise, as they can support 3 5/8" layers of drywall, and with the possibility ofgreen glue in between it seems like the direction to think towards. If the fireplace was going to be removed, the house jacked up 4 ft, and the windows all custom built, then the semi independent ceiling resting on the walls would be the way to go. but working that type of ceiling design in this just seems too elaborate, and unnecessar, although I'm of course open to any suggestions. Even though relative to the rsic-1 clips it's cheaper, I think the ceiling height would be the limiting factor anyway, as space is premium, especially the ceiling.

    I found http://www.pac-intl.com and they seem to have a lot cool variations on the rsic-1. They got back to me after about 3 days, when I asked them about spacing/pattern for 12" oc as it's not listen on the site, they responded w a graphic, and saying to use the figures for 16 oc. I would obviously have to figure in the extra clips.

    Does anyone have or know anyone who has had experience with this company? They have a thorough website and offer test data from riverbank laboratories.

    Also they have a putty to put over outlets, this could prove very useful as there is an outlet that protrudes through the floor deck above. Seems kinda pricy, but what isn't, when the words studio or custom are involved. Are they/ that putty type in general effective, even if overpriced? We only would need a few. Are there better alternatives?

    Anyway, now that everything is down to the studs, we re gonna do a sound test w some amps and some speakers to see what we got going on, especially regarding the fireplace. Again do to the limitations it's not expected that a bomb shelter is gonna be there, but it should be a fun project overall, and a great chance to try my brand new makita 12 sliding miter saw and stand!!!!! Gonna get the best blade I can afford for my new (very heavy) baby, thinking forrest chopmaster. Got the stock blade which got good ratings as a 'useable' blade, for any rougher everyday tasks, and a freud (researching better) big box blade for the good old framing lumber. After years of borrowing, I finally pulled the trigger, w the makita being the far more practical choice for my weekend warrior self, than the uber saw the festool kapex. (I drool over well engineered things :)) ramble over.

    Random Problem areas I can see right now are the beam, which would prob be buried in a soffit used for trapping and lighting. Also the staircase to the left (which I hope I have a pic of). Maintaining ISO in a similar staircase is in that chapter, but this one is a little different, as is the overall design. And def a very questionable area of the project.

    Any thoughts and suggestions are very much appreciated, the pics of the finished theatere are of one I found on line that was similar in shape and size, so something of a rough template, but w the doors wide open. Thanks!!!!!

    Attached Files:

  2. pcrecord

    pcrecord Don't you want the best recording like I do ? Well-Known Member

    I did my second build of home theaters 2 yr ago.
    Audio wise, I didn't really think about the sound of movies because it's the same room as my control room. So I was more concerne about mixing purpose when I built it. I got a side wall full with shelves of movies (yeah not copies but a lot of second hand originals). The shelves act as a immense diffuser which is a good thing because the opposite wall is a staircase with a storage bellow it (full of drum parts) on which I added a few accoustic pannel for the early reflections.

    Well I can go on with how I did it but it's not important. The point is that I had a control room in mind.
    I threated the room accordingly and it paid off because the movies are sounding very good. The room is still a bit live but I don't hear a big verb or ping pong delays and the frequency range is somewhat flat. (at least there's no peak jumping at you).

    My movie PA is far from flat and clean but it suites the purpose of what movies need and I guess being in a control room made it more enjoyable. So I'm happy !
  3. DonnyThompson

    DonnyThompson Distinguished Member

    I would think that Rod's book would come in handy for a project like this, no?
  4. kmetal

    kmetal Kyle P. Gushue Well-Known Member

    Eh good Ol DVDs. Did you use any channel or clips for your drywall PC?

    As far as acoustic treatment I'm thinking flattering more than flat, that said when a bunch of sound geeks get together undoubtably some mixing isn't out of the question, again in the realm of entertainment.

    Affects the shell layer goes up I was thinking of a lightweight fabric false wall behind the screen, hiding the front 3 speakers. Figured mount each speaker on a stack of cinder blocks, or something far from figured out yet, right on the concrete floor and be done w it . Then it's just audio to the front, video and power to the projector, and another set of audio for the rears, prob thru the ceiling or wall.

    Just throwing a lot out there as I don't know whole lot about theaters, or sound for them. Any caution tales or anything is surely welcome!
  5. kmetal

    kmetal Kyle P. Gushue Well-Known Member

    Yeah I picked it up like 5 or so years ago when my cousin wanted a a little studio made and I knew nada about what was special about acoustic construction. That thing has made it's cost back hundreds of times over. There it is lol.

    I actually got to speak w rod one time, he's unbelievably knowledgable, he was cool, had interesting stories. And look how good max's studio came out! Besides screw ups, most of what I know about the construction part of acoustics is from that book and this site, as well as js an gs. There's some truly amazing places out there, the studios themselves are works of art.
  6. pcrecord

    pcrecord Don't you want the best recording like I do ? Well-Known Member

    Yeah a lot of DVDs but I'm adding blurays now ;)

    I haven't done anything special to the walls except the one which is communicating to the recording room.
    I did double walls with rockwool with a 2 inches space between them.
    But I isoleted the ceilling completely with rockwool and installed a suspended ceilling. That way you hear less of it upstairs.
  7. kmetal

    kmetal Kyle P. Gushue Well-Known Member

    How are you supporting the walls? Are they attach to the joists? This is such a critical point in the design. Especially w any potential deflection from people moving around upstairs, I think it's the critical part of a msm system, and key flanking paths. The book has some good details on on where to incorporate what clips to use, and attach what where, so I'm not thinking using the rsic clips, and hat channel, won't be too different from the rc channel in the drawings. But still the clips are new to me, although I have used rc channel before. It's kind of a bit more of a pita that just wood frames and drywall, but space is tight. Were planning on fluffy insulation for most things, except acoustic panels, going to incorporate the superchunk traps wherever possible. It's more readily available and cheaper around here, and there's no evidence to support the added cost of having it burning behind inches worth of drywall.

    Pac international has these http://www.pac-intl.com/rsic_cwb.html

    They have a standard, a double deflection, and one other one, that I'm kind of unclear about the differences. They seem to look different from the ones in the book, which look more like interlocking U shapes w neoprene in between. Gonna have to look around a bit more and try to maybe get some more info about test performance of the different options, or if it's just based on load capacity.
  8. pcrecord

    pcrecord Don't you want the best recording like I do ? Well-Known Member

    I'm sure that you will have a better construction than mine. With 3k of budget for the entire construction, I had to compromise. And of course, it is in my girlfriend's house so I had some restrictions.

    When I got there, 2/3 of the basement was finished leaving a bare part for tools and storage.
    My priority was to make a drum bearable. So I thought of doing a room within a room to be a good idea.
    We striped down the ceilling and removed the wall that communicate with the bare part of the basement.
    I sealed the end of the sidewalls with isolation to stop the sound from traveling in them and I built a wall with a 2 doors and a sliding window door that I split in 2 parts using one part in the first wall.

    I built the recording room supporting its own ceilling leaving a 2'' air space between the upstair joist and its ceilling and the same space between the walls with 2 doors facing each others.
    DSC01788.JPG DSC01789.JPG DSC01794.JPG

    It is far from perfect because the recording room is small. But for now it gets the job done.
    kmetal likes this.
  9. kmetal

    kmetal Kyle P. Gushue Well-Known Member

    Wow it's been a while huh.? Lots and lots going on between the studios and theater and life I'm general but here's some more pics. I've just about finished the under decking drywalls 3rd and final layer. Phew. like a lot of things studio extremely tedious, but should prove rewarding.

    I left the questionable bays open to while I deal w the pipes. There are some ISO hangers available from pac International that seem to be up to the task, but my bigger concern is where the pipes go through the blocking above one of the beams.

    I was trying to think about what to do and all I could think of was make sure the pipes have clearance thru the board and the pack w mineral wool and claulk? But I can't seem to recall seeing any pictures of this being dealt with, so any links and thoughts would be helpful. I'm packing the existing wall bays with the drywall layers in the meantime. Really want to make sure I don't make the worng move with these pipes. So far I've only filled in all the clear bays that are definately gonna need it. Other than that still suss ing out the many many important small details. image.jpg

    image.jpg image.jpg
    image.jpg image.jpg image.jpg

    Btw those aren't the finishe pics, I have just about finishe putting the new solid block bridging and ledger boards in. I ordered bulk backer rod in 1/8 and 5/8 and for lime 250$ I got what's looking to be plenty! Still far far cheaper than little 20' bags from home cheapo. Even if the rest melted we have 'saved' hundreds.
    I am/have been using the illustrations in build it like the pros and putting things together accordingly. It's fun when people want to do it right and the real things looks exist like the drawings. It's a cool part of carpentry and trade work in general.

    Also loving my new makita sliding miter saw and cordless brad nailer. Hand nailing 8ft strips of drywall into the bay's while holding them up sucked, so the nailer works great one jamb in over 1000 shots. The saw is pure butter.
    pcrecord likes this.
  10. Space

    Space Well-Known Member

    " but my bigger concern is where the pipes go through the blocking above one of the beams."

    In a lower floor, a penetration should have a fire rated caulk to resist, if a fire started in this lower area, the ability for the fire to spread upwards.

    This assumes the penetration has access to an upper level.

    So while those pipes (copper) have been there for some time, you may want to consider using a pipe wrap on the pipes to remove vibration.
    kmetal likes this.
  11. MadMax

    MadMax Well-Known Member

    There... fixed!
  12. Space

    Space Well-Known Member

    Satans Handcream in a gunable tube:)
  13. MadMax

    MadMax Well-Known Member

    Yup... To do otherwise is to stab one's self in the head with a brick.
  14. kmetal

    kmetal Kyle P. Gushue Well-Known Member

    It's been a while. I'll have some photos of progress. But we reached the point a while ago where it was time to solify the plans and start working out all the fine details, and settle the design. So really nothing beyond the ceiling bay packing is done, and there are still some problem areas I've left open until the design is final. Between the contractor, and the evoloving gear lists and designs we are quite a ways away from more hammer screw gun fun. But that ceiling was enough for me for quite a while w 12" oc, and variances over an inch in actual width, exhausting is a good word. But it's necessary to do, and do as correctly as possible. Glad it's over. Here's some rough design ideas, as a starting point. It's going to have a log cabin theme, so a great opportunity to use some polys, and convex shaped bass trapping. That's the current idea anyway, which can change. There are a lot of questions I have, and things to talk about specifically. Many things... Lol, so this is just a basic convo starter as far as the design goes.

    The white areas to the right bottm are an existing bathroom, and the larger one to the right is the basement area w a single garage door access. On the far right wall in this area is the existing electrical panel.

    The current idea being thrown around is for the 'room' adjacent to the speakers, actually be an acoustic partition and not have any drywall. It would function as storage and rack access, with the rack area being the whit rectangle The doing wall between the screen area, and the wall across from the bathroom area would be these soft walls. The other outer boundaries typical of the other ISO walla, and defin the overall hard boundaries around the room. Thinking a combo of rigid and fluffy fiberglass. The only hard boundary would be the door. The room would function as storage, and acces to the back of the rack, which will house the gear. The general thought behind this was maxim ing the cubic ft, in the theater area. Also we were going to have a dedicated machine room, but it got seemingly unessaraily complicated w ventilation for a basic thing. So we decided (so far...) on a showpiece type rack that functions like any other ventilated rack, just have a display case type look from the front, with glass, and accent lighting.

    Again I know there are lots of things to go over here, just figured I'd throw out some rough design ideas as I'm working thought them. Also the speakers are for perspective, something less cluttered will be incorporated as it goes.

    Fyi I haven't had a computer for a while now, I'm using a free app for my iPad called 'formit' which is as close to sketch up as I could find. Until I get my new cpu, it's all I got.



    Attached Files:

  15. kmetal

    kmetal Kyle P. Gushue Well-Known Member

    Ps, that mess to the left of the sweet spot is the entry door and staircase that is an area on contention, so it's left like that for now. It's absolutly one of the main warts in an Otherwise nicely open existing area.
  16. Space

    Space Well-Known Member

    I do not understand the question. You have things you are saying but I have no reference from what you say using the images, there is no reference in the images that correlate to what it is you are suggesting and at what point it is in the room you are referring to.

    Could you be more specific with 1) your description and 2) a description on the image that supports the idea?
  17. kmetal

    kmetal Kyle P. Gushue Well-Known Member

    Sorry, long day, I'll try to explain better.

    The first image is a basic cad drawing my buddy did of the existing basements dimensions. The pictures from the top of the thread show this area as is in real life. I'll just put the thumbnail as a ref. I'm going to try and do a better job labeling the pictures, so In the future it's easier. It should be noted if I forgot to mention, the top of this drawing is below grade and a typical resdential concrete foundation wall. Since the ground is sloped, the bottom, or 'rear wall' is a 'walkout' door, and at level. I'm not formally trained in acoustics, or construction/engineering, so there's some holes in my vocabulary and understanding, needless to say I'll try my best to learn, an explain lol.

    The top wall (left top in picture) is refered to as the 'front wall' or 'screen wall' of the theater when we talk about it so Ill use that convention here unless there's an easier/better way, I consider that north in the drawing. The rear wall, at the bottom, is actually where the glass sliding glass doors are in the basement. These open up and walk out to the back yard. For now, the working plan is to have a heavy theater curtain in fine of that.

    To the left side, in the middle, that rectangle sticking out, is the area for staircase down to the basement and a hall to a laundry room. This is a particular area of concern, when the final design comes together as far as maintains isolation, but for now it can be considered basically 'out of the picture'.

    To the right side, the 3'11 wide, section that sticks out to the right side defines the outer boundary of the basement, the the bottom. The broken lines above it, depict where an existing wall was, an also show where the colums are located. These columns support the beam, which is part of the main support system for the house. This narrow rectangular area was a hallway, and is going to be included as part of the theaters' available space. Directly above the 'hallway' is an area defined by broken lines at the top, and left. The top, is a hard boundary, the existing foundation wall. The broken line to the left (top center of drawing) shows another beam.


    This is a better angle of the 3d sketch that correlates more to the first pic. The plain white rectangle to the far right illustrates the area of the basement unavailable to the theater, it has a door to the outside at the bottom of it, which isn't in the drawing. It's a single bay garage style door. It it where the main electrical service comes into the house, and it's roughly to scale. The other plain white rectagle, to the bottoms right is an existing bathroom. It has been ripped to the studs on the 'hallway' side, and left with its existing paneling and pluming on the inside. This is another area of focus when it comes to consturction details, but for now I'm considering it an existing boundary. The bottom of the bathroom rectangle is a wall that is the exterior of the house, as well as the ineterior boundary of the bathroom.

    The 'nook' area directly to the left of the bathroom shows the wall that defines the bathroom. This nook is currently thought to be going to be a kitchenette area. The pluming for the bathroom sink/toilet, run thru the exiting wall between the bathroom and this nook. A small fridge, flatop, sink, and microwave will live in this area. The huge concern for this are is the ceiling, and existing plumbing that runs thru it. I've touched on this in the other posts, and another important area as when the final construction plans are together.

    The floor standing side speaker are for illustration purposes and have already been removed in the current rendition I'm working in. Speaker configuration will eventually Include 2-4 ceiling speakers. On each side will be 2 side speakers, and the rear will have 2 directly on the rear wall, (which in reality is a sliding glass door, so the speakers may hang from the Ceiling back there). The front will have two 2-4 18" subs, as well as the LCR speakers.

    To the left of the "couch" is the fireplace, which is indicated by a little ledge. I have already done some work to the drawings, but want to clear these up first, so the existing conditions are clear.

    The area that is one I was questioning before is the use of the area above the 'hallway'. This area is currently open, and only the support columns currently exist. These cant be moved.

    the idea for this area that we were throwing around was Initally to be a machine room. It's still a possibility, as pretty much anything is design wise, at this point. Brainstorming, I was thinking instead of an isolated machine room, it's area be included acoustically in the theater. The hard boundary to the top is a basement foundation wall, and the one to the right would be an iso wall spearating the theatre area, and rest of basement.

    My idea was to make an isolated ventilated rack to house the electronics, and use the room instead as a storage area / bass trap. The room would also allow clear easy access to the back of the rack, and the wiring. The walls of this 'room' would be essentially thick baffles and not ISO style walls. The idea being that we would tune that wall to absorb our mids highs and let the lows pass thru, and utilize that area to add bass treatment. The rack, would be the plain white rectagle, in this area, is the purpose place to put the rack. Next to that is a support column, and next to that is a purpose doorway. This would form a 'hallway'. would run under the existing support beam for the basements ceiling. My idea was trying to maximize the theaters sqf acoustically, while leaving the space useful for other reasons as well. Just an idea I'm throwing around for conversation, at the conceptual stage of the design. Once the design is more solidified we can start communicating with the contractor, and have a solid constuction plan, and adress any of the specialy concerns Jon that area. That said the homeowners have been briefed on the general concepts, and yet another time when rods book has been extremely helpful, with its clear detailed illustrations.

    My inital acoustic design questions

    Is this is even something worth considering.?

    What other layouts may work?

    Bass trapping in general in this area, and the theater in general.

    Also are the best use/design of the entry (starway) from upstairs. (-the basic ISO details are outlined in the book)

    How to best integrate polys, and rounded edges in the acoustics and asthetic design, since I haven't worked with them before. The theme is a log cabin influenced by the Pixar movie Frozen.

    I d also like to include as much bass trapping in the ceiling as possible, as there is a fairly limited amount of wall space, and wall to wall corner space. With the rear wall being a sliding glass door, it severely limits the treatment back there, and is a known limiting factor in the isolation.

    Hope this helps, and I'll be glad to try and explain anything else that i haven't cleared up. With so much to considerin these things, it's work to just think about starting a starting point :)
  18. Space

    Space Well-Known Member

    You are essentially building a critical listening area. Now while a control room needs symmetry a critical listening area needs this just as much.

    I would approach this like yes I do want to allow bass frequencies an escape I would not make it a goal to remove mid/highs. Those will go away due to the draping and trapping so you have to think about that as well. Hard surfaces allow mids and highs to live.
    kmetal likes this.
  19. kmetal

    kmetal Kyle P. Gushue Well-Known Member

    Here's some more updates. Still have lots of planning so just some photos of the shell and some problem areas.



    Ouch, this is going to be tough. gonna need some help on this area. These pipes and bays need attention. Wondering if PEX is any advantage, or if ISO hangers are all that's necessary. Any thoughts?


    Man, this is extremely tedious, but necessary. Hang once, twice, err, three times. Enjoy for a long time!

    I'll post some more soon.
    pcrecord likes this.
  20. kmetal

    kmetal Kyle P. Gushue Well-Known Member

    Kind of out of order but here's some more questions and a better organized Budget.


    Southern New England

    Budget: (basic rough)

    Construction Materials - $10-15k

    Sound System - $15k

    Wire/Power Conditioning (power/audio)- $3-5k


    HVAC - $2,500-5k (Daiken multi zone ductless mini split is placeholder)

    Appliances- tba

    Furniture- tba

    ISO Clips -$3,500 (WIC, RISC -1)

    Fabric / Finish - tba

    Lighting / networking - ($1-2k?)

    Green Glue-$3k (if included)

    MISC Costs- +30%

    Goal- a quiet comfortable room to relax in, listen to and play music, and of course, watch films.

    Construction tasks- new walls, ceiling system, mass up existing structure, new electrical,

    Isolation expectations- to maximize isolation within the constraints of the existing structures ability, and/or the clip based Isolation system limitations.

    Known limitations / restrictions / problems :

    -low ceiling height 7'6


    -entry stairway

    -existing windows / sliding glass doors

    -existing bathroom and laundry room

    -existing plumbing

    -existing electrical

    There are some very concentrated areas in this project that I have been unable to find much resourceful material on. Mainly, the fireplace/chimney, which has a gas insert, goes directly upstairs (yikes). The entry stairs from the upper level are also an area of concern, and something I've not yet had to deal with in my experience. Mainly maintaining the Isolation, in the allotted space. Also there are some extent,let narrow ceiling bays, and contractions of pipes. Making massing up the existing ceiling bays a compromising affair. I'm looking for the best way to approach this.


    New electrical service for theater (star grounding)

    Demolition / modification of existing structure.

    Re working /routing of existing plumbing

    Open to any new ideas!!!!


    -how to efficiently manage the fire place while maintain its function, and maintain isolation.

    -Entry door system.

    -entry stairs

    -HVAC incorporation

    -adequate ventilation for machine room.?

    -window plug system to allow a natural light?

    Pipe location and mounting. No clue about mounting.

    Sorry bout the whitespace I copied and pasted from onenote.

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