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post #211 of 220 Old 08-29-2019, 09:17 AM - Thread Starter
LJG
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Originally Posted by gwthacker View Post
Well, let us know when you crack the code on the design!


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OK, I have determined 2 sources of sound leakage which should not be too hard to correct. The first is an air gap between the outer side ring of the lens case and the inner ring of the MDF Hush Box design.

The second air gap is between the inner side of the ring of the lens case and the lens of the projector.

Will be attacking the outer ring air gap with green glue sealant, will probably use Neoprene or Foam weather stripping for the inner side as I don't want sealant near the interior of the projector.

Any other ideas welcomed for a sound barrier material.
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post #212 of 220 Old 08-31-2019, 03:52 PM - Thread Starter
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2 layers of 2lb mass loaded vinyl sheets cut out to lens opening and screwed into inner MDF hush box sealed air gap entirely, and is now as quiet or quieter than 1 layer of port glass.
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post #213 of 220 Old 09-01-2019, 05:37 AM
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We (www.displaytechnologies.co.uk) sell two standard types of hush solutions for projection. Single and double glazed portholes and a system we dubbed the “hush plate”.

The hush plate uses a very dense foam that is CNC cut to match the projector lens it is going with so there is no air gap. We use some other materials to reduce friction so the foam can move with lens movement without losing performance.

The port holes are some of our most popular options with the double glazed being by far the most common choice. They are designed such that they are easily removed for access to the lens or for cleaning.

The glass we use is AR coated on both sides and has an average transmission of just under 99% through the rec2020 wavelengths. That means even the double glazed units are 98% efficient.

The hush plate is a pain to manufacture (since it is custom to the lens) and does not isolate as well as even the single glazed porthole. So we find it is normally a no brainier choice to go with a porthole.

I am personally horrified at the idea of getting green glue anywhere near valuable electronics- stuff is enough of a pain on dry wall!!!

We do a lot of hush boxes and typically we aim for 40dB reduction in noise level which needs the porthole.

Neil Davidson - DT Screens
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post #214 of 220 Old 09-02-2019, 06:16 AM
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Originally Posted by LJG View Post
I am still experimenting with this design, it is definitely not as quiet as with glass. I will need to insulate better between the gap of Sony outer ring and the MDF ring of the glassless design. I am thinking possibly experimenting with Green Glue Noiseproofing sealant as it is easy to work with and easily removed. I will also experiment with neoprene strips. Also I need to determine if this space gap is the only noise leakage and if there is some noise leakage between the projector and the outer ring.

It may, in the end, be a tradeoff between video purity and a bit less "soundproofing".
From memory: Wolfgang used many layers of circuitboard, stuck together. CNC-ed holes for tightest fit still allowing for lens turning/moving.
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post #215 of 220 Old 09-02-2019, 10:23 AM
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I believe you mentioned earlier in the thread you were also incorporating multiple LED TV's in addition to the projector/screen? Or did I misunderstand?

Would love to see pictures of that too (If they were posted, I somehow missed them).
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post #216 of 220 Old 09-02-2019, 11:14 AM - Thread Starter
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Originally Posted by steveklein View Post
I believe you mentioned earlier in the thread you were also incorporating multiple LED TV's in addition to the projector/screen? Or did I misunderstand?

Would love to see pictures of that too (If they were posted, I somehow missed them).
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post #217 of 220 Old 09-02-2019, 11:17 AM - Thread Starter
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Originally Posted by donaldk View Post
From memory: Wolfgang used many layers of circuitboard, stuck together. CNC-ed holes for tightest fit still allowing for lens turning/moving.
Using 2 - 2lb sheets of mass loaded vinyl did the trick perfectly. The way the glass less port was designed just the lens fits through the port hole and the mlv cut to the lens and installed on the forward side of port openings solves all the sound leakage problem 100 percent.
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post #218 of 220 Old 09-05-2019, 06:50 AM - Thread Starter
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Inside of Hush Box port hole sealed with 2 layers of MLV cut to lens circumference and attached to MDF. The white green glue noise proofing sealant is very easy to work with, a lot different than the green glue compound which I would not recommend anywhere near the lens.
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post #219 of 220 Old 09-05-2019, 07:00 AM - Thread Starter
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Up next is Automating Lumagen Aspect Ratio with the Crestron system to fully automate screen masking and projector lens memories.
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post #220 of 220 Old 10-16-2019, 02:31 PM - Thread Starter
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Curt Hoyt will be on site starting Tuesday to finalize room tuning.
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