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Coffee Tables and Ventilation

Discussion in 'Projectors, Screens & Video Processors' started by BeerDrinker, Jul 29, 2002.

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  1. BeerDrinker

    BeerDrinker
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    Hope it is OK to post this here, maybe it should go in DIY.
    Having just joined the CRT gang with a ECP3101, I am happy with a floor mount solution and like the idea of a coffee table enclosure.
    I have searched both here and over on AVS and everybody naturally talks about the need for good ventilation.
    HCC has featured some great pics from installs that include professional coffee tables that do not appear to have great ventilation. I am wondering if anybody has seen such installs and knows how the heat is carried away. Is there ducting and fans under the floor etc?
    Thanks for reading, and hopefully replying. I would like to think I could build a suitable box for my PJ.
    Bob.
     
  2. MALC

    MALC
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    I am not an expert in this but from the ones I've seen there is nothing underneath, the air circulating around the PJ is what helps keep it cool even if it is a small area. Mind you that's not to someone somewhere could make something to keep it cool. I have heard of a small fan being mounted in the same area blowing onto the pj but I would of thought that would add to the noise, perhaps if it is enclosed it would be a lot quieter.
     
  3. BeerDrinker

    BeerDrinker
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    Thanks for the info. The noise is not too much of an issue since this Electrohome is pretty quiet anyway. It was more to make a piece of furniture to house the unit. I was thinking of using fretwork on the side of the enclosure so ensuring air flow to the sides and back. Unless the shots we see of coffee tables in the magazines are taken from an angle to show their 'best side', they really do look quite enclosed.
    Also I would like to say I'm glad to have joined the CRT gang, just wish I had done it earlier, now I know it is a never ending tweaking life for my HT. The information here from all you experts has been most informative, and has been responsible for getting me into this. (Got to blame somebody when the wife asks!)
    Cheers
    Bob.
     
  4. meep

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    Berrdrinker,

    Be sure to let us know if you find a solutuion. I'm at exabtly the smae stage and have the same concerns.
     
  5. Roland @ B4

    Roland @ B4
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    I actually prefer the image from a PJ mounted on the floor. More of the light is reflected back at you. and genrally most CRT projectiors are quieter floor mounted.

    Study where the air goes in and where most of the heat is generated on your projector and allow holes to suit.

    Most of the setups I have seen in the Mags do not allow proper verntialtion and I know of at least two so called top end shops that have taken more trouble with what it looks like rather than if the projector will carry on working.

    A few thoughts that I would consider.
    Hot air rises so make sure that air can escape and does not build.
    Never take the cover off the projector it will bhave been designed to asist the cooling.
    Make sure your table allows easy access to all the controls and inputs without a major rebuild of the table.
    What will happen to a drink if it is spilt ,will it go inside the PJ?
     
  6. BeerDrinker

    BeerDrinker
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    Thanks for the replies, and Meep I will let you know how I get on. (By the way great site and HT room you have there).
    I thought some of those in the mags looked a little too enclosed Roland. Thanks for your ideas, I will allow an overhang and some kind of lip hopefully to stop any drink spills. The ECP 3101 as I am sure you know has its fans on the side of the lower board housing, and there is a metal grill above the tubes. I would think some of the fretwork material used to decorate over central heating radiators would do nicely for the sides and rear, plus leaving some size of gap at the rear towards the table top would allow extra heat away from the tube grill, and give access to the inbuilt keypad.
    Now all I have to do is put my ideas into action, easier said than done for me I'm afraid!
    Regards
    Bob.
     
  7. Baggy

    Baggy
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    BeerDrinker,
    I've got my Marquee mounted in a "coffee table".
    My setup is in my loft conversion and ceiling mounting wasn't an option.
    I had it made with a removable top and back to provide access and also extra ventillation on those hot days we sometimes get.
    Kevin
     
  8. meep

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    Baggy

    Any chance of a few photos?

    meep
     
  9. BeerDrinker

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    Baggy, sounds good and as Meep says, any chance of a photo or two? It would be great to see what you have done.

    Regards
    Bob.
     
  10. Baggy

    Baggy
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  11. BeerDrinker

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    Nice one Kevin. Making me jealous looking at all that space. My HT room is just 12' x 12', and I still have to put up a partition wall to the kitchen.
    Good looking table, I take it you do not find heat a problem then?
    Your DIY skills look excellent, when I get round to making my table I will take photos in the dark without flash!
    Now if I could just clear out that loft............

    Regards
    Bob.
     
  12. Baggy

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    BeerDrinker,

    Don't want to mislead you.I never made it myself,I got someone I know to make it for me.
    Under normal use I have no problems with heat but as it's in my loft the ambient temperature can get a bit warm.On those occasions I take the lid off to allow extra cooling.
    The room's about 16'x14' which makes it pretty reasonable, I just have to watch out for the beams,not a problem when you're sitting down.
    Kevin
     
  13. sheggsl

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    Great coffee table Baggy. I have just recently purchase a Sony G70 and will also be floor mounting. As my DIY skills are almost nill, I will need to get someone to build one for me.

    I will appreciate help for any contact names. I live in Surrey just a couple of miles from Croydon.
     
  14. Baggy

    Baggy
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    sheggsl,
    I just went to a local joiner I knew, showed him some pictures I'd found from doing searches on the forums etc, gave him the dimensions of my Marquee ,allowed for suitable clearance for ventilation and my table's what we came up with.
    One of the links I used for idea's was Vance45 from AVS.
    Here's a link to his table.
    http://www.geocities.com/vance45_2000/vancepage4.html

    Kevin
     
  15. sheggsl

    sheggsl
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    Thanks for the reply Kevin, that's exactly what I am hoping to do. Just have a couple of questions though, how did you decide on the required clearance of the projector from the ground i.e. how did you determine the base height of the cabinet? I am assuming that you had the projector in the cabinet before you began converging.

    I have found a cabinet maker that might possibly be able to build one, however the CRT people tell me that I need to have the CRT in its proper setting first, then get a cabinet built after which I will have to get the whole thing re-converged. Something about having to be accurate about the vertical height of the projector from the floor before getting the coffee table built. Sounds like a double calibration expense to me.
     
  16. Baggy

    Baggy
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    sheggsl,
    I was advised that the feet of my Marquee should have been approx level with the bottom of the screen.
    But for the G70 have you tried PJCalc to work out your distances and what size screen are you using?
     
  17. Gordon @ Convergent AV

    Gordon @ Convergent AV
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    Forget PJCALC....

    Ideally you want to use as much of the tube face as possible. This requires having as little tilt on projector tubes as possible to allow the image width to be cranked out to near the edges of the tube face. 10-15mm is close enough. Too close and you are in danger of heating seals and causing premature failure of tube.

    I'd do this....

    Feed a test pattern to projector at highest reolution you are likely to use.
    Set everything to mid points. Then do a rough geometric set up (forget convergence just do green geometry)
    Turn down contrast and look in green tube.
    Cover red and blue
    Centre pattern on face of tube looking in to green lens. (once you've got aspect ratio right etc.)
    Use size control to push size out to use as much of phosphor as is safely possible
    Now move the projector so that it is overscanning the screen by an inch all around.
    Now, chances are you'll find if you raise projector, then tilt raise the back of it as well, you'll use less Keystone and this will allow you to move projector a little closer.
    If you have a 16:9 screen you'll be able to go closer than the specs suggest as well.....

    So your installer calibrator is sort of right. You do need to do a geometric set up (very rough) to find out the best distance from screen to projector.

    Gordon
    P.S This was a very rushed written explanation. I don't think I missed any stages but if you don't understand the principles then don't try it yourself, get the installer guy to do it...or if all esle fails I've heard there's this guy in Scotland who might be able to help ;-)
     
  18. meep

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    Sheggsel

    when initially installing your projector, you (or your technician), would have to calculate the required height your projector needs to be raised off the ground to suit your screen installation (distance, screen vertical placement etc.) This height would have been calculated from tables in the installation manual or indeed using special software such as pjcalc for sony models (plus a little fairy dust!)

    Whether you were planning to enclose you projector or not, you would at least need to have build or acquire some from of platform built to this height.

    Once the platform was correctly positioned (distance from screen), and the projector installed on it, your calibration could commence.

    If you were to build a new enclosure, the design of which required the movement of the projector, then you will need to re-converge.

    I assume from your post that you had someone in to calibrate/converge your pj? That being the case, your have a number of options;

    1. Have the enclosure built and call your technician when complete to re-converge.

    2. Spend some time learning how to do basic set-up and convergence yourself (not very difficult with the resources here and a little technical savvy)

    3. Design your enclosure in such a way as to not require projector movement.

    On point 3: Though I'm more than happy to converge my pj myself (I'm a tweaker at heart), I have installed my pj on a 4" platform as dictated by my calculations. Now I'm going to build a "bottomless" enclosure which will simply lower down over the projector. If you took this approach, you would not have to re-calibrate.

    (I'm actually going to build the enclosure in two parts with a removeable top section for easy access to projector controls)

    have a look at my HT site, linked below, to see pictures of what i mean. I'm only half-way there but you get the idea. (you'll be most interested in the environment and projector sections)

    Regards

    Peter
     
  19. Baggy

    Baggy
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    Guys,
    Thanks for chipping in.

    Gordon,
    How did you get on with your homemade scart lead for the CS-1?

    Kevin
     
  20. BeerDrinker

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    Meep, your room just looks better all the time. The platform for the PJ is an excellent idea. A fine photo for your front page. My table is on a slight hold while the room is being stripped for re-decoration. I have a big light problem with an approx. 8 ft wide and 4 1/2 ft high window to cope with, goodness only knows what a blackout blind that size would cost!
    I'm also searching for 44.8 M 5 watt resistor to do the focus mod on my ECP 3101, lots of info over on AVS Forum, but very hard to find suitable components.
    I'm glad to see this sparked off a few posts, look forward to seeing everybodies finished tables.
    Bob.
     
  21. meep

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    Bob,

    Thanks for the kind words. And it's not finished yet!!!

    That's a big window indeed! The way the Velux blinds work, they don't "sit in" to the window next to the frame but rather overlap on the frame, some distance from the glass. The blind itelf runs in a u-shaped metal rail which helps with eliminating light leaking from around the edges.

    maybe you could DIY something similar with a slightly oversized window blind? (I'm not sure how much regular black-out material costs though).

    I would advise to make this a priority as the diference is INCREDIBLE. One word of caution, you'll need some form of remote control on your lighting though if you want to void tripping over yourself on the way to and from your sofa!

    Peter
     
  22. sheggsl

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    Great room Meep,

    I bet the sound will be gorgeous once the carpets are down. Just the sort of room I am looking at. I am also in the process of converting a loft and having an extension built. Out of interest what is the headroom height and width in your room? Also where did you obtain your black out blinds from, are they manual or remote controlled?
     
  23. meep

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    sheggsl

    Thanks. I'm thinking of upgrading the speakers & amp before trivial things like carpet!

    The room is about 20'x 30' so lots of space. Blackout blinds are by Velux, I'm sure they have details on their website; I got them from a local curtain material supplier who's a Velux agent. Their tailor made for the model of Velux you have and come with mounting rails etc.

    I'm not sure but I'd expect you can buy the same fabric in regular roller blind form. The blinds are manual (the electric Velux blinds cost a small fortune). No content really as the windows are very accessible so no reaching required.

    Good luck with the conversion!

    Peter
     
  24. meep

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    Now, a further question.....

    I'm about to embark on the table enclosure for my Sony 1271 but, as some of you may know, I'm planning to upgrade this unit sometime in the future.

    bearing that in mind, I don't want to make a nice unit now only to find in the future that a larger projector won't fit.

    Could anyone offer advice on what's the largest projector people use (808? 1209? etc.) What are the dimensions (or a link to same) and anything else to bear in mind (position of lenses etc.) if I'm trying to build a "one size fits all" enclosure?

    I haven't seen that many CRTs so advice from those withy collections in their living room :rolleyes: would be appreciated!

    Thanks all

    Peter
     
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