# Hushbox - lens or treated glass?



## symphonic1985 (Aug 18, 2009)

Hi everyone,

When I built my projector screen I benefited enormously from the expertise on this forum and am extremely satisfied a year later! So I'm back...

I'm making a hushbox for my Epson TW600. it's not ceiling mounted so I'll be going for a chimney type design with 140 mm computer fans to push the air through. How far away I vent things will depend on how noisy the inlet/outlet is.

What I'm unsure about is what to do in front of the lens. Ideally I would like to project from further back. Since I need to add some glass to the front of the box to seal it, maybe I could use an additional focusing lens instead.

What would be a good lens choice? I don't need it to be adjustable, I just want a smaller image without aberration. Brightness should be a problem since I like running in Theatre Black 2 anyway - I have spare lumens.

Price is somewhat important since I need to move every couple of years and can't take everything with me. I'm in Germany at the moment.

Can't wait to hear what you guys think.


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## Alan Brown (Jun 7, 2006)

Do a search for "port glass" and plan on mounting it at a slight angle. It will be much less costly than a conversion lens.

Best regards and beautiful pictures,
Alan Brown, President
CinemaQuest, Inc.
A Lion AV Consultants Affiliate

"Advancing the art and science of electronic imaging"


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## symphonic1985 (Aug 18, 2009)

Thanks for the advice Alan. I found that the German company Schott makes anti-reflective glass that is used in museums. That should be pretty good for port glass.


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## Alan Brown (Jun 7, 2006)

symphonic1985 said:


> Thanks for the advice Alan. I found that the German company Schott makes anti-reflective glass that is used in museums. That should be pretty good for port glass.


I'm not familiar with that type of product, and don't recommend guessing. You ought to verify with the manufacturer that it can be used for your purpose and that it doesn't have any optical properties that might alter the character of the image. http://www.opticalcoatings.com/applications/projection.html ; http://www.tristatetheatre.com/Port Window Page.htm


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## Ile (Nov 23, 2010)

I have used cellular rubber seal between lens barrel and hushbox in my hushboxes for crt projectors.
http://www.curtpalme.com/forum/files/husboxandrear_speakers_178.jpg
http://www.curtpalme.com/forum/files/dscn2280_431.jpg

It's better that there is no extra glass between lens and screen.

I had fully isolated cooling system from theater room in my previous department, that was only way to get good result with my projector and it was also good extra that projector didn't heat theater room.

If there is air vent at your projector front plate 2" long tube from hushbox front wall to inwards would help to get room for air circulation.


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