Ask the Expert: HD Upside Down
Q. I'm interested in buying a front projector for ceiling mounting. I realize that when projectors are turned upside down for a ceiling mount, a circuit inverts the image so you don't have to watch the movie standing on your head. I also realize that there's another circuit to reverse the image left-to-right for rear-projection. Is this standard on all projectors, and if not, how do I know if a projector can perform these feats before buying? Also, since almost all circuitry applied to a signal can be detrimental, does Sound & Vision test the quality of this circuitry? Frederick Hart Orlando, FL
A: SEAN GREER, Owner, Experience AV Home Theater, Montrose, CO, says: To the best of my knowledge, there's no digital projector made at this time that doesn't have a facility for selecting ceiling or rear projection. As for the question of image quality, it's a good one, given all the processing and scaling that goes on with video signals these days. S&V editors tell me they don't usually check this function, but fortunately, with a digital projector, there's really no need to "process" the image (in the traditional sense of that word) to change the display orientation. It's really a matter of just rerouting the correct bit of data to the correct point on the screen for the desired orientation. No scaling or alteration of the signal is performed, just a relocation of where the data comes out on the pixel grid of the projector's microdisplay chip, whether it's DLP, LCD, or LCoS.