Building a small home theatre room

Discussion in 'Audio Visual' started by whatdoesthisdo, Sep 17, 2018.

  1. pH@tTm@N

    pH@tTm@N Member

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    Sorry Zee, you are wrong on the subs, spot on with all else. Subs at front is just usually handy as there is space between screen and you. If you are talking modern small "HT" when you use 3" tiny speakers drivers that don't go below 150Hz, then of course the sub needs to be with the speakers, because it will have to play bass, not just sub bass. I'm not talking about toy little systems :p also IF the subs are next to you, and your mains and centre 3 metres away, you need a delay to the subs so they don't play early, or you will hear the first speaker - subs in this case.

    For real bass when you have mains that do to 100Hz (hopefully more like to 40Hz) loudly:-
    Many books with studies on the subject, and for the most sub bass response in any seat in a room you put a sub in the middle of each wall, but usually not possible or feasible.

    A wall of bass is also up there for even response in any seat, front or back slightly preferred over sides. Remember anything below about 60hz is directionless because a full wave length ends up being longer than the walls/room size. You also get a "room pressure" effect for those big Low Frequency Effect (LFE) explosions etc in action scenes.

    A little here on multiple subs
     
  2. Zee

    Zee Member

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    I should have said “allow for”. Bass is one of those things where I find the “move the sub around” technique works best before final position is determined, though, multiples is usually the way to go (as in multiple subs that are then tuned).

    You make some interesting points, actually - though, directionless, yes, you do still get standing waves, nulls/nods etc. (always fun to do a low frequency sweep with a client in the room), so positioning matters, though you point that out, too.

    As for speakers, the lower frequencies get harder to push, and having bookshelf/floor standers that go down to 40Hz is good and well (and I do), most people have not got the grunt to properly drive them. I use an old 300w/ch Adcom power amp to drive my Legacy Victorias. But most will use whatever receiver they buy from Harvey/Bing/whatever - and we all know that power ratings on those things vary from “lies” to “blatant lies”. So, for most, 80-100Hz is the lower limit for their receiver, and you need subs to deal with the lower frequencies.

    Edit - nice vid, the op should find that very handy!
    Z...
     
    Last edited: Mar 17, 2019
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  3. pH@tTm@N

    pH@tTm@N Member

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    Ah yeah, agree with the AV amps... my aging Yammy RX-A3030 only powers the surround speakers, all the heavy lifting by various power amps. It says it has a million watts per channel, but when measured it can only do the rated when when 1 single channel is driven. Load up 7 channels and like most you end up sagging down to probably 30wrms a channel - which is why efficiency is king in HT speakers designed to run of these AV amps. Low's is where the most power is required of an amp, and bigger speakers are also less efficient than tweeters.

    Sidetrack:-
    I build a few speakers and subs, so my Left/Right output from the AV receiver get split by miniDSP to an amp per driver active setup. This way costs more up front of course (or like many DIY's, previous stuff you still have), but I never have to pay for crossover components. The amount on EQ needed in room below 80Hz is very interesting! I run two 18" ported subs in the front corners of the room, port tuned at 16Hz and in free air, -3dB is at 18Hz in the sims. In my room I have a massive peak at 38Hz that is easy to EQ out, then a dip either side of it that I think only placement could fix, then another smooth peak at 22Hz to below what I can measure (but can feel) that I leave alone because "house curve" LOL.

    So for my main left right I have two TD15H 15's by Accoustic Elegance http://aespeakers.com/ getting ~300wrms from iNuke 3000(I like full range L/R because I like loud music as much as movies)
    then 250wrms of overkill from an old marantz feeding 6.5" scan speak revelators for 100hz to 2.2Khz
    then 50wrms DIY chip amps for the 1" scan speak revelator tweets, and due to their efficiency they only need about 20wrms to keep up.

    the big 18" stereo integrity subs https://stereointegrity.com/product-category/subs/ on the AV sub channel take all a iNuke 6000 can give :) which is not 3000wrms per channel advertised but just over 600wrms x2 at 4ohms. PS. I'm sure someone needs two of their 24" subs!
     
    Last edited: Mar 17, 2019
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  4. OP
    OP
    whatdoesthisdo

    whatdoesthisdo Member

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    Arm is getting a little better every day so over the weekend I decided to chip away.

    Got the a/c lowered and then built the left hand side soffit framing.
    upload_2019-4-2_13-6-43.png

    Struggling with the hidden door stricker and automation components. The goal is to have a wall with a hidden door in it and by pressing a slate tile it will open the door. There's heaps of stuff on amazon but I am worried about using power supplies that are from no named brands.

    Thinking about using something like this and flush mounting it behind a slate tile. I will need to come up with a way to make the tile push the button but also look like it is a part of the wall. Thinking I will just cut the tile out and glue it to the button. The button will then release this. Alos not really sure how I am going to power all this and wire it as I suck at the electrical stuff.
     
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  5. OP
    OP
    whatdoesthisdo

    whatdoesthisdo Member

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    Finished of the framing. Now gyprock, wiring and lights. Oh and brick up the window.



    upload_2019-4-7_17-23-5.png
     
  6. Holdenkicks

    Holdenkicks Member

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    wire lights on two circuits so you can have lights over the seats on and other lights off.
     
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  7. VYAcclaim

    VYAcclaim Member

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    Awesome project you go going along. Has it progressed much recently?
     
  8. Sphinx2000

    Sphinx2000 Member

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    So the ceiling bulkhead work is purely cosmetic? or can you not get in the ceiling for speaker/wire work (i.e two storeys, etc)?
     
    Last edited: Jun 11, 2019
  9. OP
    OP
    whatdoesthisdo

    whatdoesthisdo Member

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    Is that so you can see the remote? lol.

    Thanks mate. It has but only slightly cause a few walls were bothering me, so I tore them down lol.

    Last weekend with the help of the misses, the old man and my mum, we were able to get the 3.6mtr length of gyprock up. It's starting to take shape now.
    upload_2019-6-11_22-12-51.png

    Once I get back to qld, I'll finish off the corner beading and plaster ready for painting this weekend.

    Purely cosmetic. I love doing this stuff and it keeps me off the streets. lol

    I know it's not media related but if anyone is interested in the other areas we have pulled down the entrance wall which blocked off the lounge and kitchen and now really opens up the house.

    Before
    upload_2019-6-11_22-23-20.png

    During
    upload_2019-6-11_22-24-46.png
    *using these cupboards in the butlers pantry until our cabinetry is ready. Bloody heavy for a guy with a broken shoulder, so used a skateboard to move it lol.

    upload_2019-6-11_22-26-43.png

    upload_2019-6-11_22-27-12.png

    Nearly After
    upload_2019-6-11_22-28-2.png

    Have fully removed the walls by the black bin now, sorry don't have an updated photo.
     
  10. VYAcclaim

    VYAcclaim Member

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    Taking that wall out mustve been nice. It looks nice and open in that area now
     
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  11. Holdenkicks

    Holdenkicks Member

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    Thats one of about a dozen reasons I can think of :)
     
  12. Benno1988

    Benno1988 Member

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    Did you replace the wind bracing you took out :p
     
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  13. neRok

    neRok Member

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    Just read through thread, and was going to ask what was involved in removing that wall, but now you've answered. That's much easier than brick. Looks like some good changes btw :thumbup:

    The new timber wall you put in, did you just secure the top to whatever ceiling beams were already in the area, or do you have to put some more in?

    Same question with your soffit framing. It looks like a lot more timber than I would expect. Are the beams along the wall secured to the wall, and then the rest secured to those beams? What is the original ceiling height, and the height under the soffit?
     
  14. Benno1988

    Benno1988 Member

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    Depends on the age of yours house/how the roof is framed.

    New homes will tend to have timber trusses (600-900mm spacing). Plasterboard will then tend to be secured to ceiling battens, often "tophats" (light gauge steel). Sometimes its direct stick to the truss bottom chords.

    The proper way would be to build the new top plate slightly under the trusses/battens, then use the wall stabilising brackets (little L brackets with slotted holes for the nails) to ensure it doesn't wobble, but still allows up and down truss movement.

    If your wall runs parallel between two trusses, you add in "noggings" between the trusses, then secure your little brackets to these.

    Hard to tell form photos but looks like it was built hard under the plasterboard, possibly then screwed through into the battens?
     
  15. OP
    OP
    whatdoesthisdo

    whatdoesthisdo Member

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    Unfortunately the roof joists were running the same way as the wall in that section so I had to fit noggins(?) in between the joists to give me something to screw into.

    Yeah I probably went overkill on this, I did 450mm spacings when 600 is the standard for ceilings but I had never done anything like this before and I struggled to find anything online. This is where software like sketchup is awesome. I did about five different designs and this is the one I decided one but If I was to do it again I think 600 spacings would have been fine.

    In saying that with my size room and the design (led ledge) I did need to add extra timber in the corners to have something to screw the the gyprock too. You don't want ends being able to flex or move.

    The back beams are attached to the wall studs and I made a box section for the internal area which are attacked to the ceiling joists or extra noggins I had to fit. I am not sure if that makes sense, let me know if you want more clarification.

    Original height is the standard ~2400 and I came down 300 (i think, I can double check when i get home), so that would make it 2100 underneath.

    I am glad I did this before the seat riser as the height I planned would have made it tight for taller people. I think the riser will probably only be ~150mm

    Sorry, didn't see your message till after I posted. Yes, as above, but instead of battens, I had to use noggins and I did use tophats, keeping the gyprock in place doesn't effect this at all.
     
    Last edited: Jul 1, 2019
  16. neRok

    neRok Member

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    Makes sense, cheers.
    No trusses in mine. I would just call it stick built. And it seems nearly every wall has a post sitting on it to support the roof, or it's supporting a steel beam across a "large" span.
     
  17. PrawnBoy

    PrawnBoy Member

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    I managed to score an old projector from the office. Plan to use it in the lounge once in a while for movies etc. It's only 720p, however it's a decentish Epson one (when it was new) and the picture quality and brightness is actually pretty decent. We have brand new white walls in the lounge which will hopefully make for a good area to project onto.

    Jealous of this plan though lmao
     

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