I have a client who is building an addition to his house. He's putting in two home theater areas (one kind of high end, one low end). The AV/network/telco utility closet is right by the main home theater area. The TV is going on one wall about 20' away from the AV/network/telco utility closet. My thought was to purchase one 25' HDMI cable and put in an HDMI Coupler keystone, to hook up his new flat panel TV that is going on the wall back to the AV closet where the receivers/BD players and all that stuff is.

He has a second home theatre on the first floor about 50' cable length away from the AV closet. I've read conflicting stories when doing a Google search about HDMI max cable length, most of them saying technically the HDMI spec doesn't have a maximum cable length, but a spec for loss in order to stay compliant with the HDMI standard.

Are 50' unamped HDMI cables okay for that length? Is it necessary to get HDMI baluns & CAT5e to hook up that TV?