After rendering the theatre room step, I realised I need to work out where I want the speakers and screen positioned so I have a plan ready to go when I want to run speaker and RCA cables (otherwise we'll get to that point of the build where we have to do our data cables and potentially run out of time without getting what we need done!)
This great guide has a handy list of speaker locations/angles etc.
First was to determine the size screen we want- 110" sounds a suitable size for the space, then to work out primary seating position and head height. I measured my ear height in our current lounge suite and applied that height about the center of the theatre raised platform, then created a cylinder and marked out the recommended angles for the speakers from that position.
The guide recommends around ear height, so that's where I'll put wall plates - if the speakers need to be mounted higher to clear the furniture then they can be wall mounted above the plates and still look neat as they'll only just be popping above the edge of the seating.
Screen position has center just a touch above eye height; this supposedly gives a bit of a theatre-esque feel and also allows a bit of height between any entertainment unit we choose to use and the center speaker - it also allows the center speaker to be closer to ear level where centering the screen to eye height may have caused it to be a little too far off axis.
The next drama was projector distance from the screen. In discussions and electrical plans with the builders I'd specified the center of the room for projector location. A quick spot of research shows that standard projectors are around 3.5-4.5m to acheive a 110" image. Whoops, better revise that! Height is recommended above the screen by no more than around .5x the height of the screen which I've shown as centerline of the wall plates on the wall above the posters below:
Emailed the image below to the builder- we need to move the ceiling powerpoint to about 300mm from the wall adjoining the bedroom.
We haven't organised a projector yet (and in fact it'll be one of the later things we do once we're moved in) but LED/Laser 1080P looks to be the way to go - no lamps to worry about!
At least now when it comes time to run the cables I'll know where on the walls I need to run speaker and RCA cables to!
I guess next will be data points!