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Discussion Starter #1
I'm building a hushbox for my ceiling mounted LT150. The hushbox will use a 3" fan that puts the exhaust into my ceiling (I will drill a 3" hole into my ceiling drywall). I expect that this heat will dissipate similarly to the 10 100w light fixtures in my ceiling. The main advantage of this design is that the unit is completely sealed, except for the 3" intake hole. This should make it very quiet.


The construction of the hushbox will be made with 0.5" and 1" pine, and then painted ceiling white.


Below is my design. Could someone please check it out to make sure there are no fatal flaws. After I build it, I can post the final design will all parts used.

http://www.avsforum.com/ubb/image_up...ushbox_top.gif

http://www.avsforum.com/ubb/image_up...shbox_side.gif


Thanks,

Ross.
 

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I haven't got my LT150 yet. http://www.avsforum.com/ubb/smile.gif but I saw dwgs of LT150 in user manual.

Why don't you put a exhaust fan of hushbox just next to exhaust of LT150?

Mixing of hot and cold air will be minimized by doing so.

And I think it is better put airintake hole at opposite side of exhaust fan.

JIMO.


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Jason
 

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Discussion Starter #3
I could put the hushbox exhaust close to the LT150 exhaust. Originally I designed this so the 3" fan blew into the room, not ceiling, so I wanted it far from the noisy fan.


BTW, note there is an LT150 intake right next to the LT150 exhaust, so that is a negative for putting the hushbox exhaust close to the LT150 exhaust.


It would be great to see other designs for the LT150 hushbox that people have already built and tested.


Ross.
 

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Perhaps a hole for the cables. http://www.avsforum.com/ubb/smile.gif


How do you level it? Looks like there may be three threaded bolts in 3 of the corners. You could also put a temperature monitor inside.

-=-

Mark
 

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Discussion Starter #5
Mark,

I do have cable holes in board 3, not shown in the above diagram. Board 5 is used for tilt adjustment -- that's what the 3 bolts/springs are used for.


Ross.
 

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I take it board 7 is installed after the projecter is leveled. Hope this turns out, I can use it on my LT150.

(Although it's my DILA that really needs a hush box).

-=-

Mark
 

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Ross,

Great design! I've been thinking about building a hushbox myself for the LT150. Here's a few ideas:

For the intake filter I was planning on getting a HEPA filter from sears for a vaccuum cleaner...they're small and come in different sizes. I haven't picked one out yet but I'm sure I can find one about 3x5" that could be placed on the side (board 4) for easy cleaning/replacement.

I was planning on putting the exhaust hole into my ceiling as well, but want to try to isolate the intake side from the exhaust. I was thinking about using thick weather stripping to accomplish this. Say between your board6-5, board5-lt150, and lt150-board7. I was also going to place a board (full height) from the rear of the box to the lt150 to close off the exhaust side...almost inline with where your power outlet is.

I'm thinking of making mine out of 3/4 MDF (better sound absorbtion? - not sure) instead of pine. Also I was going to place some carpet remenents inside to absorb sound. Another member lined his box with automotive firewall sound absorbtion (felt/foam?) material...same stuff used to quiet your engine noise and it's obviously heat resistant...just haven't found any at the local auto zone as yet.

Good luck with the project.


Regards,

Drew
 

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Ross-


Your design looks great except for one fatal flaw- you have the projector oriented wrong for a ceiling mount! The LT150 must be inverted (upside down) for a ceiling mount. That will basically mean all of the items on your drawing must be flip-flopped, save for the exhaust port.


Feel free to resubmit your drawings to the planning commission as soon as they're ready. http://www.avsforum.com/ubb/smile.gif


Good Luck,

Kirk
 

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Discussion Starter #9
Kirk,

The design is such that board 6 is screwed to the ceiling. That is, it is correct, and the design does not have to be flipped.


Ross.
 

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Gotcha. So drawing 1 is looking at the bottom of the hushbox and drawing 2 is upside down?


Was there any particular reason you designed it so that the projector will need to be mounted to board 5 as opposed to just resting on it (if the rest of the box features were reversed)? I ask because that's how the "Whisperflow" boxes are designed.


Kirk
 

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Discussion Starter #11
Kirk,

In order to not require keystone correction, a ceiling mounted LT150 has to be upsidedown in order to project to a wall. This is true with most projectors I know of.


Ross.
 

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Ross-


We're still not on the same page. I know that the LT-150 has to be inverted in a ceiling mount configuration. I was just wondering why you designed your box so that the projector must be screwed into board 5 (inverted of course). Wouldn't it be easier just to make board 5 a shelf onto which the projector would rest (again inverted)? This would have the added benefit of providing an extra layer of sound proofing between the PJ and the listener in the room below. Check out this link to visualize what I'm describing:

http://www.whisperflow.com


I think you have a great design already, (facets of which I will undoubtedly borrow), and was just wondering why you opted for that particular design element.


Kirk
 

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Discussion Starter #13
Kurt,

I choose this design because I though it would be easier to build and more sturdy. I think it is more sturdy because I use the 3 "ceiling mount" screws to secure the LT150. Note there is also an air intake on the top of the LT150, which needs to be clear (a potential problem if the LT150 is resting on its top).


In an updated design, I use 3/4" pine with 1" sound deadening board, which should provide ample noise reduction -- my guess is more than using only acrylic.


Ross.
 

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This is a great post. I've been following it closely since the first day because I'm going to be building some kind of hushbox when I ceiling mount my LT150. There was another thread awhile back by Thumper where he took an LT150 apart and discussed where all the air intakes and exhausts where. I'm worried that the design here doesn't do much to isolate the intake ports and a lot of hot air recirculation will occur. Got any thoughts on this? I know from experience with my projector that a lot of hot air comes out the right side of the thing.



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-- Hoover2
 

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If the space above the ceiling doesn't get too hot, you could route your intake through the ceiling also. That way your box can be fairly well sealed from the room.


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Best regards,

Alan
 

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I see several mentions of 'optical glass'. Where is this purchased (Home Depot?), how is it different and can you tell the difference? Also, isn't the Whisperflow made of plexi-glass, is this any more optically correct?


David.
 

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I found this glass at Edmund Industrial Optics:


Tech Specâ„¢ High Efficiency Anti-Reflection Coated Windows


• Yield Ultra High Transmission

• Eliminate Back Reflections

• Reduce Glare on Visual Displays


These glass windows are coated on both sides with a Clear Display Anti-Reflection coating (CDARâ„¢), reducing reflectance to less than 0.5%. Back reflections are virtually eliminated by the coating, so these windows offer improved readability when used in industrial displays or computer monitors. Their high transmission makes them ideal for many other optical applications.


Follow this link:
http://www.edmundoptics.com/IOD/Disp...Productid=1919


Prices range from about $15 to $50 (US) depending on the size you get.


The whisperflow box appears to have a cut out in the plexiglass for the projector lens to shine through. Plexiglass itself is a plastic (with all the imperfections inherent there) and would be horrible to shine a light through. I think the whisperflow comes with a piece of optical glass you can optionally insert in the light path.




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-- Hoover2
 

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Quote:
Originally posted by Hoover2:


Plexiglass ...would be horrible to shine a light through. I think the whisperflow comes with a piece of optical glass ...


This is correct. The wisperflow comes with, or is available with, the high-quality Edmund glass.


Jeff



[This message has been edited by Jeffrey (edited 09-07-2001).]
 
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