I have a pitched ceiling in my living room where I plan to put 4 speakers. I see that HSU recommends turning the speakers upside down for high placement, but these will be angled bc of the sloped ceiling. Should I place the speakers upright or turn them upon installation?
My guess is it doesn't matter very much. I think what you will want is for the tweeter to have a straight vector to your listening position as possible, but that is just a guess. Unless the speakers are relatively close, I can't believe there would be a significant difference in an up or down orientation.
The orientation does matter some in the crossover range.
As shadyj says, it's most important to try to aim them so that the tweeter axes point toward the listeners' ears. Aside from that, it's best to orient the speakers so that the tweeters are physically closer to the listeners' ears than the woofers for the best crossover response.