Hello again,

I'd like to make a valiant attempt to sound isolate my HT space. However, my current plan calls for a projector projecting through a 6 inch hole cut through the wall to the adjoining projector/equipment room.

1st Problem-the equipment room has no sound isolationd whatsoever. From what I have read, the hole in the rear wall will be a major source for flanking noise. I know the hole can be covered with optical glass, but the glass will have far lower STC than the double GG wall it resides in.

2nd problem- Now that we are in the 1080P era with projectors and Blue Ray etc, won't the absolute performance of the projector be compromised to some degree with the sheet of optical glass in front of it?

3rd problem- This will make The throw distance quite long, something close to 23ft for a 110 inch max diag 16:9 screen. I've noticed that there aren't very many options out there for long throw on the new projectors like the new JVC or Sony 1080p's.

The obvious advantages though, would be nice clean look, greatly reduced in theater noise, and reduced heat in theater, and more headroom.

Do the advantages outweigh the disadvantages in your opinions?

20/20

Could you not build a box for the projector in the equipment room and insulate that? Though that would likely have its own issues (heat, sound) you'd think that it would buffer the ambient noise in the equipment room.

But I'm a total n00b so I'd solicit more experienced opinions before making any decisions. ;)

I did the same thing - put all the equipment in an extra room in the back of the cinema - have a look in my construction thread.

1. Yes you are right that the glass will have a lower STC than the rest of your wall, but the hole needed for projection is small compared to the rest of the wall. So I wouldn't it consider a real problem.

2. If you use a high quality optical AR coated glass you are going to loose < 1% of light lost in reflection. No problem here!

3. This could be a killer point - it is dependeing on the projector/lens you want to use. Just make sure to check the projector specs if your throw distance / screen size is within the possible range.

Just my 2c... ;)

Space Moose,
Good suggestion, didn't think of that, but I would be worried about projector ventilation with that setup. Could work though as others have built hushboxs for projectors in the room.

Zinema,
Great theater. I noticed you went through a lot of trouble to build an angled outlet box for your projector. Is this necessary? My plans call for a simple 6 inch round hole through cinderblock, lined with a matte black painted pipe. I do feel your pain regarding working with concrete. I have the 1 1/8 inch Bosch version of your hammerdrill/chisel. What a pain in the neck. My concrete is so nasty, I have melted the tips off 4 SDS concrete bits so far. Nothing like having molten metal drip back down on you from the hole you are trying to drill.

In general,
I have found that there is a definite reduction in resolution when looking through binoculars through window glass, both single and double pane. That's what concerns me about the glass in front of the projector. I'm not worried about losing light output. I don't know if this is true for the projection optics or not, but I'd hate to get a multi thousand dollar, long throw lens and then potentially hamper it's ultimate resolution with an additional piece of glass in the optical path. In the 480p/720p era, this probably didn't matter, but it might with 1080P?

Regarding long throw, there seems to be a big jump in projector price at the new 1080p level. I have not done a complete search, but SOTA long throw looks to be double the price or more. IE current state of the art 1080p standard throw Sony or the new JVC run less than 10,000. A comparable 1080p long throw like the new Marantz looks to be around 24,000. It does not seem wrth an extra $10-$15,000 to go long throw, unless I'm missing something important here.

Great theater. I noticed you went through a lot of trouble to build an angled outlet box for your projector. Is this necessary? My plans call for a simple 6 inch round hole through cinderblock, lined with a matte black painted pipe. I do feel your pain regarding working with concrete. I have the 1 1/8 inch Bosch version of your hammerdrill/chisel. What a pain in the neck. My concrete is so nasty, I have melted the tips off 4 SDS concrete bits so far. Nothing like having molten metal drip back down on you from the hole you are trying to drill.

Thanks, I stopped counting my totally ruined SDS concrete bits. :eek:
I had to do this design since my rear wall will be ~18" thick (including the false wall to hide the rear speakers once the fabric frames are mounted. So the light beam is expanding and I had to make the front part larger than the rear part.

I have found that there is a definite reduction in resolution when looking through binoculars through window glass, both single and double pane. That's what concerns me about the glass in front of the projector. I'm not worried about losing light output. I don't know if this is true for the projection optics or not, but I'd hate to get a multi thousand dollar, long throw lens and then potentially hamper it's ultimate resolution with an additional piece of glass in the optical path. In the 480p/720p era, this probably didn't matter, but it might with 1080P?

You can't compare standard window glass to optical grade AR coated glass. You will never loose resolution when projecting through a glass surface but you will notice two different effects depending on the quality of the glass:

- reflection: every transition of the light beam from materials of different refraction index (air/glass glass/air) will cause reflection which will reduce the intensity of the light hitting the screen (decreased brightness)

- surface flatness: if the surface of the glass (applies to both sides) is not 100% flat the pixels of your projected image will get shifted (since we assume the glass surfaces are parallel) by unequal amounts each. Which can result in non uniform focus and slightly misaligned pixels. The higher the resolution of your image is the more you might see this effect - seems like you are loosing resolution, but in fact pixels might be overlapping a bit.

Conclusion: Get a high grade optical AR coated glass and everything is fine. :D

Mike,

If I'm in an outdoor cafe in Salzburg, eating a knockerel, and I take out a pair of Swarovsky 10x42 EL's and look through them at one of your beautiful, dark haired, blue eyed fotomodels modeling for a photoshoot 100 meters away, and then look at the same fotomodel with the EL's through the AR optical glass, will I notice any reduction in the overall quality of my viewing experience?

Since you are Austrian, I will take your word for it ;)

20/20

If I'm in an outdoor cafe in Salzburg, eating a knockerel, and I take out a pair of Swarovsky 10x42 EL's and look through them at one of your beautiful, dark haired, blue eyed fotomodels modeling for a photoshoot 100 meters away, and then look at the same fotomodel with the EL's through the AR optical glass, will I notice any reduction in the overall quality of my viewing experience?

Nope - even when looking trough non AR coated glass she will be still beautiful, dark haired and blue eyed! :D :D

I'd love to find a web resource for figuring out what to use for my projector hole glass in my theater.