I’m glad to see this topic come up again. I’ve been researching this since PLIIZ and DSX were first announced. It just happened to coincidentally align with my inclination to add a second set of surround speakers in between the existing set and my mains. I started studying Dolby, THX, Audyssey and DTS. All four of them have their own ideas to where speakers should be placed, the type of speakers used, and the type of sound field that is best. It gets very confusing. It also creates problems if you need to pull wires through walls, floor joists, ceilings….. If you don’t care if wires are strung about and visible, a person could experiment and find a solution that works best for their room or their personal preference. In my case, that just won’t work. Wires strung all over the place look tacky to me and I won’t have it. That means I get to cut sheet rock and do a lot of cussing.
If you read Dolby’s information, height speakers go directly above your mains. The type of speaker they recommend is not clear to me. They recommend neither directional nor non-directional. It appears to be somewhere in between. They speak to “ambient” sound like rain and helicopters, but they also want the speakers to create an imaging that gives the listener a somewhat directional perspective. I think a set of QS speakers would work for this application, but then again, a set of directional speakers would probably work too.
If you read Audyssey’s information, they want you to place height speakers at 45 deg to the listening position and pointed directly to the center (prime) listening position. This tells me that they prefer a directional speaker. They also have width speakers, but they suggest they be placed at ear level and somewhere between the height speakers and the surround speakers. These speakers, from what I can interpret, should be non-directional. I don’t know about anyone else, but I don’t want a set of speakers at ear level in the middle of my room, I’d prefer to have these closer to my ceiling as my furniture occupies the middle of my room.
DTS has not come out with any height or width processing yet, but I’m certain they will. I have always had a preference to DTS, so I’m hesitant to commit to any particular layout until I see what DTS comes out with. I do know that if DTS could corner the consumer market, you would see a very different speaker layout than you do now. DTS has a strong preference for use of directional speakers, all aimed at the very center of the room (they call the sweet spot), spaced somewhat evenly around the room. You would also see a speaker directly above you in the ceiling, pointing down to the “sweet spot”. Due to the unconventionality of this, and consumer resistance, DTS never did move this model forward. There is also the problem that this layout is more of a benefit to a room where seating is limited to one position, which would not work very well for the majority of consumers.
THX appears to be sitting on the fence and they don’t have a strong opinion one way or the other, but they do seam to prefer width over height. I think THX is waiting to see what the market does before they commit to Dolby or Audyssey or DTS or come up with their own preferred speaker layout. Personally, I don’t pay much attention to THX.
