If you are running an amp you'll only need to cable from the video out of your amp to the projector, because the amp does all the video switching with your DVD etc.

You can buy multicore cable (for video) and either run this in the slab through conduit when it is getting poured, or under the dropped ceiling as you said.

I'd also run the cabling for rear speakers at the same time.

You can PM for more info / ideas if you want, I did this shit for 3 years.

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