Thanks Avi, I'll try to answer some of your questions.
Room is 2.3m wide x 5m long and pj will be at most 4.5m away (lens to screen.)
Seating about 3m away from screen.
Walls will be dark brown, ceiling white (or not?), floor will be brown carpet.
Since this is a garage conversion i can mount pj how i want so will put on DIY shelf on back wall.
Using projectorcentral calculator for HD1 throw of 4.5m, it recommends a screen width of 163cm (64"), is this correct? It does seem rather small. Or can the image be widened on the JVC to say fill an 80" screen?
Welshy
With a throw of 4.5m you can achieve an image size of about 75" to 140" depending on the zoom position. The smaller image size will result in greater contrast and given your room width the limit would be around 100" diagonal (49x87" image area + borders ~6")
To maximise the contrast I would recommend a dark coloured ceiling and the use of velvet type material were possible. Reflected light bounced off the wall etc can affect the contrast ratio. Given the proximity of the walls and ceiling to the screen I would suggest 6' of velvet around the side walls at the sceen end of the room.
Your wall mount should be fine and will avoid too much lens shift.
With 100" or less I would use a matte white unity gain screen based on this room. This will still produce a punchy image with good black levels without any off axis shift or hot spots of a higher gain material. If you want a very brighter image then a 1.3 gain. I would avoid very high gain in your setup.
There are lots of options and I assume you will be using a fixed screen? If so Da-Lite (Da Mat (1) or Cinema Vision materials (1.3)) and Carada offer decent quality at a reasonable price (<£1000). There is also Stewart and their ST130 is often quoted as a reference standard but it is expensive (think £2500+ for a 92" fixed screen).
Hope this helps.
AVI
