Originally Posted by cannga
Marc, not an expert but this is how best I understood it, as confirmed to me by a pro (filmmixer): At least in *my* case of testing Theta Casablanca 7.1.4 using the DTS:X Demo Disc's channel call-out, 2 and 3 above is how it is supposed to be. Nothing wrong. Basically it's remapping function using available speakers to produce a particular sound in a particular position.
For example, with #2
, the channel call-out is asking for a sound directly above my front speaker (front height), let's say left front height. If my setup has a left front height speaker, that speaker alone would make sound. However... since my setup only has left top front, to reproduce a left front height sound, the Theta has to use left top front AND left main front to reproduce left front height sound. It's remapping at work. Hope this helps.
Filmmixer explained this properly.
However, dts created this issue (yes, it's an issue) by following Dolby's nomenclature of HEIGHT and TOP for positioning, but mucking up the angles and screwing up manufacturers attempt for finding a proper universal placement.
Dolby's definition of TOPS is that they be placed ~45° & 135° and HEIGHTS ~30° & 150°.
Dts [in their infinite wisdom] defined TOPS at ~60° & 120° and HEIGHTS ~45° & 135°.
Dts:X does not have a placement which corresponds to Dolby's HEIGHTS at 30° & 150°.
Whether speakers are mounted on-wall, on-ceiling, or in-ceiling is of no consequence. Elevation Angle is what matters.
Dts HEIGHTS and Dolby TOPS correspond. Unfortunately, if you chose TOPS Atmos would render properly (without phantom imaging) but dts:x would not. It HEIGHTS were selected, it was optimal for dts:X but not Atmos.
It was expected that manufacturers would rectify this. Has anyone tested the latest D+M (ADI) or Yamaha (TI) AVRs or firmware? Theta's (ADI) implementation did not and doesn't even have an option to select HEIGHTS and now Lyngdorf (ADI) has not.
The solution is easy (in my mind), always report to the dts decoder that HEIGHTS are deployed and not TOPS. No one [in their right minds, at least] is building around dts:X primarily and placing speakers at 60° & 120°
Until then, two separate configs have to be maintained and switched between (easy on Yamahas). This may end up the case if Lyngdorf does not address it.
Originally Posted by sdurani
Check out the DTS:X slides at the following link: http://184.108.40.206/wordpress/?p=92868
As with Atmos, there are two layers of speakers above the listeners: Heights and Tops. All 8 Heights all are evenly spaced on a ring at 45° elevation, all 4 Tops are evenly spaced on a ring at 60° elevation. I guess VOG can be considered a third layer, at 90° elevation.
Originally Posted by sdurani
Atmos Tops fall close to DTS:X Heights. Problem is, if you designate that location as Tops in your AVR, it will be correct for Atmos but incorrect for DTS:X (which calls those same locations "Heights"). If you designate that location as Heights in your AVR, it will be correct for DTS:X but incorrect for Atmos (which calls those same locations "Tops"). Hence the compromise of one of the formats.