My first attempt at a torus was less than successful, not the screen itself but I found that I was unhappy with the convergence and focus issues, and couldn't get enough bow from my G70 to compensate (some units have this quirk while others don't - your bow needs to start around 128 or so to have enough downward bow for the traditional curves commonly quoted). While I loved the look of the picture, the convergence and a few other issues were deal-killers.
The screen is ~ 88x48, the first attempt had curves on the horizontal edges about 7" deep, and about 2.5" deep on the vertical edges. The bow problem I've already mentioned, but the focus was impossible, the G70 just can't hack such a difference between center and edges very well. Since my screen is 'surface mounted' and protrudes off the wall, it protruded alot, about 11" total at the corners. Also I used one 80mm fan in a fanbox, and while it wasn't very loud, the rpm was fairly high and the noise it did make was fairly objectionable when the system was off (we walk through the den constantly and it just got on my nerves). Also I hoped to quiet the pj in the future so at that point I couldn't see how I'd get the fan to shut up when I did get the pj quiet. Lastly (this is still an issue and I'm surprised nobody has mentioned it) the curved screen has an annoying quality of echoing back at you when you talk in the room, esp from the sweet spot. I don't think this has too much effect on the audio but it must have an effect (I'm curious other's views on this).
So, I was one unhappy camper after spending $300 and alot of sweat. Finally I parked the screen in the garage and almost offered it to anyone fool enough to come get it. Well after getting tired of the flat pearlbrite I decided it would be a good experiment to cut gentler curves in the edges and try again. I figured it would help all the convergence issues and also require less suck power from the fan so I could use some really quiet fans. I have used the Silencer
fan for years for pc projects and it's very quiet and reliable, the down side being low cfm and static pressure ratings. I decided to put in two silencers and not use fan boxes but instead something very simple and quick. I framed a little box in the two bottom corners 1/2" bigger than the fan and cut a hole to the outside so the fans can just pump air out. Quiet will come from the fact that the silencer is very quiet and besides most of the noise is airflow and the fanbox may just make it worse. I made the most direct clean air path I could. Here's one of the fanboxes (there is one in each bottom corner) from the inside showing the fan 'mounting' and wiring. The fan just nestles in the open-cell foam so there is no coupling between fan and frame.http://homeyb.no-ip.com/images/torus...ite_fanbox.jpg
Here's a shot of the outside once mounted that gives a better idea of the whole thing.http://homeyb.no-ip.com/images/torus...ox_outside.jpg
The two fans are not quite enough to totally pull the curve, after two days they have sucked the screen down 1.375 of the 1.75 dish. I don't see a problem here though, the center is the brightest anyway so it really doesn't stick out. To me quiet is the more important concern. The two fans have a much lower tone, and are barely audible from the seats in a quiet room.
The new screen box is much less dished, as I mentioned. The corners stick out 6.325" from the wall. The curve on the horizontal side is 3.5" deep, giving a low point on that edge that is 2.875" from the wall. The vertical edge dips 1.75" to a low point of 4.625" from the wall. These are much gentler curves than my last, approximately half the curvature, a little more than half on the vertical edges since I had less problems from that curve than the horizontal edges.
And of course the gratuitous screen shots, actually you can see the falloff in brightness toward the right edge (as always more evident in pictures but still present), it's really much better than the flat screen, no comparison actually.http://homeyb.no-ip.com/images/torus...shot_front.jpg
And one where the curve is evident just for fun.http://homeyb.no-ip.com/images/torus...nshot_side.jpg
I'm very pleased that I picked this project up again, the result is outstanding and I think a viable option that lessens some of the convergence issues. Also I think it's going to be much easier to come up with masking for this less-curved situation. So now I just need to finish the hushbox, mask the screen, build new speakers...