Throw calculation confusion!


Active Member
I am in the process of a house renovation/rebuild and my cinema is moving rooms.

I have a Sony VPL-HW55ES and I'm tying myself up in knots trying to figure out if my setup is going to work with the new room so any help from people more knowledgeable than me would be hugely appreciated.

Viewable area of screen (with draper react 2.1 screen material gain of 1.1):

260cm wide and 146cm horizontal

From the screen wall (unfortunately the only wall in the room that will work for other reasons) to the opposite wall is 378.8cm

The throw calculator indicates I would need a throw of 360cm to utilise the full extent of my screen. Obviously, once I've factored in the depth of the PJ (46.4cm and some wiggle room for cables) I am coming up short.

Is there any way this could work? Can't get my head around using horizontal/vertical shift. Got as far as understanding they work in tandem and using one reduces the other but not much further. No option to recess the pj into the wall (backs onto our hallway and Mrs not going to permit a box protruding into the entrance hall!).

Any thoughts from the cinema building veterans on here much appreciated.....


Distinguished Member
Do you already have the screen and projector? Never mind whether it will fill the screen, you might have an issue with hot spotting. Draper / Euroscreen HQ recommendation is projector lens 1.8x screen width from screen surface to avoid hot spotting. So at 2.6m you'd ideally want your projector lens to be 4.7m from screen.

Lens shift is of no help whatsoever with throw distance - it only helps with offsetting the image from the lens centre.

Your two options are to cut a hole in the wall to increase the distance (will probably still violate the throw recommendation from Draper / Euroscreen unless a very deep hole...) or do a more complicated setup using a first surface mirror to increase the throw distance. There are some installation systems with the mirror integrated but they are quite pricey.

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