I finally got the end table/enclosure for my 7205 done, and my worst fears have been realized: It's too hot and too noisy. As you can see from the first picture, the front of the stand is completely open when in use, so plenty of air can enter. The problem is I'm apparently not getting enough of the hot air out.

The second picture is the stand with the top off; you can see the blue-gasketed exhaust fan in the upper right corner of the enclosure. It's pointed at the 7205's exhaust fan, along the projector's right side. The fan is a variable-speed, 12vdc, and is rated at 27 cfm. Running the projector in this configuration, at top speed (and noise), the air exiting the exhaust fan was barely warm--not a good sign. The right side of the projector and the inside wall of the enclosure became very warm, and once the projector's fan kicked into High mode, it stayed there.

Today I threw together four pieces of plywood to form a makeshift duct, shown in the third picture, installed alongside the projector and leading back to the exhaust fan. This seemed to help considerably; the air exiting the enclosure was noticeably warmer with the duct than without. However, while testing the duct this afternoon, the 7205's fan again stepped up to High mode and stayed there. After I turned the projector off, I pulled out the duct and found that the projector and the inside of the enclosure seemed at least as warm as they did without the duct. The front right corner of the projector was almost too hot to touch! The icing on the cake is that the exhaust fan is already too noisy.

I just recalled I have another 12vdc fan I might try that's more powerful than this one--but it's almost certainly even noisier. The stand's in our living room, so I can't get fancy with a big remote fan with ducting to the outside. Anyone have any suggestions?

Thanks,
Jeff

The projector is side venting - Infocus specs are that there must be 2' clearance on both sides so it can breathe and its own fans can do its job. You have about 2" which is why it is suffocating. You need a much wider box with your in/out vents on the sides routed back to wherever you are dumping the noise and hot air.

You're right, kras, as usual. I just checked the manual, and I remember now that I thought that was part of the safety precaution regarding the expoding lamp possibility, not ventilation.

I can't put a five and a half foot wide box in the living room; a compromise might consist of strategically located holes on the side of the enclosure, as you suggest, with the exhaust fan on the side of the 7205's exhaust, and ducted to the rear.

Jeff

too noisy.
Jeff


Looks like a projector sitting in a big echo chamber to me.

I don't see any acoustical treatment on the inside of the box to absorb the noise that is being bounced around by the hard plywood surfaces.

I was just gonna say that...I would bet it is quieter and less hot without the hushbox at all! Have you tried that?

Yeah, I considered that, but insulating the inside would have made the box bigger--which is a disadvantage since my wife and I will be sitting on either side of it. No enclosure means that whoever is sitting to the right of the projector would be roasted by its exhaust fans.

All in all, I'm thinking real strongly now about abandoning the enclosure and going with an inverted wall mount. Thanks for your comments; I'm off now to research Infocus ceiling mounts.

Jeff

An inverted wall mount without an enclosure is going to be really noisy. I built a (ceiling mounted) hush box for my Sharp 20K PJ because it was so noisy. Mine is only about 6" wider than the PJ on both sides and about 4" on top and bottom. I don't think the 2' requirement is important - that is an open room spec. Your table should essentially be an upside down hush box.

My box is built with baffles on either side so the sound has to go around the baffles to get out. Think of a suitably sized cardboard box with added vertical panels on either side that go from the top to about 2" from the bottom. Positive ventilation is provided by 2 very quiet 120mm Silenx computer fans (silenxusa.com) that are switched by a 12v trigger on the PJ. I built a duct that runs from the main exhaust to the fans, so the fans act almost like a vacuum sucking out the hot air. The front of my box is enclosed, with a 6"x 16"x1/4" lexan window. Thought i'd put a small optical glass window in the lexan for the picture but the lexan was so clear i could see the difference when it was in or out, so i bagged the optical glass. The important thing is that the box is closed except for relatively small inlet/outlet air openings. My box vents into the ceiling, which is an advantage you won't have, but a nearly closed box will go a long way towards making your viewing experience more enjoyable. my PJ is nearly silent now.

Take a look at Whisperflow.com for hushbox design ideas or search here - these boxes aren't that large. HT Magazine had an article on a hush box one of their editors built for a HTPC that uses a baffle-based design - perhaps you can check their website. I lined my box completely with 1/2" sound absorbing foam (hushcloth) from dB Engineering at www.800nonoise.com. if you had the air intake on a side facing away from viewers and the exhaust on the bottom, with a couple or three inches clearance below, i think you could make it fairly quiet without being big.

Good Luck!