AVS Special Member
Join Date: May 2008
Location: San Francisco - East Bay area
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One thing... well probably more than 1 thing... that people do that gets them in trouble is getting a screen that's too big for the projector. I know projector specs typically say screen size up to 200" (or some other screen size WAY bigger than you intend to use) are within the recommended size range so you figure your screen size selection is appropriate. Frankly, there aren't many home theater projectors that can achieve 16 fL for 100% white on a 120" screen. Keep in mind, that projectors with projection lamps will lose light as the lamp ages... probably half the light the projector is capable of with a new lamp once the lamp is getting to the 2/3 of life range. So if you START with 16 fL (foot-Lamberts) which is the center of the range recommended by SMPTE (Society of Motion Picture Technicians and Engineers), you'll only be seeing 8 fL or thereabouts for a fair portion of the life of the lamp. That makes for pretty dim and lifeless images. What you REALLY want is to START with close to 20 fL with the lamp in "High" mode and iris partially closed) so you can START with the lamp in LOW mode and iris at an appropriate setting and as the lamp ages and dims, you can open the iris more (you may use dynamic iris if it works well on your projector but then you haven't got that adjustment in your pocket for compensating for lamp aging). At some point when the output of the lamp dims enough, you can switch to HIGH output mode for the lamp for the rest of its life to get more light, but even then, it's likely to drift way below 16 fL
I've been in home theaters where the owner thought everything was fine with their selection of projector and screen until I measured the light output at 100% white and came up with just 5 or 6 fL. In many cases, these enthusiasts believed the hyped screen gain claims made for acoustically transparent screen materials. As far as I can tell, acoustically transparent screen gain numbers are universally at least 30% too high... screens that have CLAIMED gain numbers of 1.0-1.3 typically measure 0.6 to 0.8 gain. And that just hurts the light capability of the system even more. If you think high-gain is the way to get images that are bright enough from a large screen/modest projector combo, often times, high gain brings on-screen anomalies like uneven screen illumination or hot spotting (which can look like gray or colored grain floating a few inches in front of the screen surface).
The other thing people screw up on with screen selection... height of the ceiling is CRITICAL as you can have STRONG reflections off of a white ceiling that visibly wash out the top 20-40% of the image because the reflections are so strong. The larger the screen, the closer the top edge is going to be to the ceiling and the more likely reflections from the ceiling are likely to be troublesome. Painting the ceiling flat black helps, but using black velvet on the ceiling forward of the projection screen is even more effective. If you aren't going to paint the walls and ceiling flat black (and put black carpet on the floor), very dark neutral gray is the next best option. Screens with gain are more directional and tend to reduce problems from reflections. But... you then have to deal with less than reference quality images because of the uneven illumination or hot-spotting issue where you see grain in the center of your field of view.
Another thing people tend to do is go overboard on screen size then cheap-out on the audio part of the system. HUGE mistake, IMO. You can get an $800 subwoofer from Hsu Research that can be tuned to produce 16 Hz at 100 dB+ in average size home theater rooms (a large room in a typical home). A typical $1500 subwoofer with a 10" driver, or even 12" driver won't come CLOSE to doing 16 Hz "flat" with the rest of the subwoofer's range. You don't have to spend more on the audio system, but you do have to be damn careful what you spend money on. People tend to build sound systems with 5 or 7 TINY satellite speakers and a sub that can't fill-in the lower midrange the tiny satellite speakers can't reproduce, or if the sub CAN reproduce the lower-midrange area cleanly and loudly when needed, it won't produce much bass below 40 Hz. A system that can reproduce 16 Hz cleanly and at high levels will thrill guests more than a 120" screen versus a 90" screen.
There is WAY more to setting up a good home theater than just picking components, connecting them up, and using the system.
Then there is the issue of room acoustics. In most home theater rooms, the loudspeakers will tend to sound their best with the listener seated 7 to 10 feet from the loudspeakers. If you sit farther than that from the speakers (as is likely with large screens like the 10-footer you are considering) you get into a seating distance where reflected room sound will overwhelm direct radiated sound from the front speakers. This will make the sound much less distinct and detailed much more diffuse and homogenized. So you want a screen size and speaker distance that work together. If you pick, for example, 9 feet for the distance from the front speakers to the main seat, you'd want a screen width in the range of 68-90 inches to have a viewing angle between 35 and 45 degrees. With a 120 inch screen, you'd need to sit 12-16 feet from the screen which puts you well into the zone where reflected room sound will overwhelm direct radiated sound from the front loudspeakers. Now... the exception would be if you have a HUGE room where the walls and ceiling are FAR from the front speakers so that room reflections would be reduced in magnitude by distance traveled and the reflections would be delayed in time compared to the direct sound from the speakers due to extra distance traveled. But that's not usually a factor in home theater rooms.
If you sit closer than a 45 degree viewing angle (larger angle), you will see individual pixels in the images. HD is good but it is NOT so good that any viewing distance is OK. 4K or Ultra HD will let you sit much closer to the screen (larger viewing angle) but, most people won't "get" that and will probably sit too far from the screen to gain any real advantage from Ultra HD resolution.
"Movies is magic..." Van Dyke Parks
THX Certified Professional Video Calibration
Widescreen Review -- Home Theater & Sound