Originally Posted by lovingdvd
I saw some questions about what screen sizes may work with this pj so I did some calculations you may find helpful.
This is also based on the assumption that the RS1 does indeed put out 700 lumens @ D65 with a new bulb, and that over time an aged bulb drops by about 50% (nothing specific to JVC here). Keep in mind with most bulbs I think they hit their 50% drop off well before their rated max hours, so this further assumes that you'd replace the bulb once it got dim and well before the max rated hours...
First I present numbers for the StudioTek/Firehawk based on about 1.3 gain. Now if you go with a high power screen (essentially a must if you plan to go over 120") you can do pretty well assuming you can mount to get the high gain out of the screen. Just keep in mind that HP screens do not generally work well at all with ceiling mounts.
OK, so here are some numbers:
For a 106" Firehawk screen, 700 lumens is 27ftL which on an aged bulb is about say 13ftL so that seems rather ideal.
For a 120" Firehawk screen, 700 lumens would yield about 21ftL, and say 11ftL with an aged bulb. Still acceptable by many standards.
Once we go up from there it gets dicey... For a 133" Firehawk screen, 700 lumens would yield about 17ftL and say 8ftL with an aged bulb. IMO this is still doable if you have total light control. I'm getting 8ftL now with my Ruby and its still very enjoyable and punchy.
If you go up to a HP and can get 2.0 gain (doable, but you better be sure!), here's how the numbers change. Note that with the HP the gain varies widely based on placement - anywhere from below 1.0 to as much as about 3.0. So I'm using 2.0 as a general average but you may be able to get higher say 2.5. Ok so here goes:
For a 106" HP screen with 2.0 gain, 700 lumens would yield about 42ftL, and say 21ftL with an aged bulb.
For a 120" HP screen with 2.0 gain, 700 lumens would yield about 32ftL, and say 16ftL with an aged bulb.
For a 133" HP screen with 2.0 gain, 700 lumens is 27ftL which on an aged bulb is about say 13ftL.
Hope this is helpful. If you have specific questions about HP gains send me a PM and I'll help you estimate what your effective gain is. Then based on that we can calculate an anticipated ftL level based on your desired screen size.
Disclaimer - these numbers should be used as a rough guide. Before making any decisions please be sure to check with your dealer as I can't be sure of these numbers and remember a lot of this is based on speculation on the specs of the RS1 at this point...