[Paulo Elias]

Just for the record, and for those who are reading this posting still unaware of what Dolby Atmos is:

Since the beginning Dolby Atmos was described as an extension coded for both 7.1 Dolby TrueHD and Dolby Digital Plus. It has a series of metadata that will let it adapt itself to the number of existing speakers. The adaptation process assumes that in the setup of the system proper Atmos or non Atmos speakers are enabled. In other words, it is not a sensing or guessing algorithm! And this, mind you, works for either theatrical or in the home applications.

The Atmos information in a regular, non Atmos built, speaker system, can be conveyed by virtualization, i.e. placing sounds in space where phantom speakers would be located. There is nothing extraordinary or new about that. Early home theater installations, for example were made without a centre channel, in this case derived from in-phase left and right front channels.

In real life, this is not truly black and white as we would had hoped:

The extension specification works fine. In fact, the first Blu-Ray disc with an Atmos track (Transformers) had two separate tracks, but that was not at all necessary, so much so that subsequent discs have now only one track. If the user plays them without an Atmos decoder the extension will be ignored, simple as that.

However, speaker layouts are still open for discussion:

Ideally, a complete Atmos system would work with 4 top ceiling speakers, in addition to Dolby Enabled or Height speakers. For many people that is not doable.

In addition, there is a justified on-going dispute about the dispersion characteristics of speakers dedicated to Atmos channels. Some experts claim that ceiling speakers are too directional and therefore predictable, and others claim that Dolby Enabled and Add-on modules are not fully capable to shoot sound to the ceiling and bring it back to the listener.

In theory, a perfectly capable 7.1, non-Atmos speaker layout is the minimum requirement for proper Atmos virtualization. The 7.1 array can be either fitted with Height (DPL IIz) or Surround Back speakers.

In the manual of my NR737 receiver Onkyo says that "either Height or Surround Back speakers are required", otherwise Atmos will not work. This means I can keep or install Surround Back speakers and still enjoy Atmos playback, in a "7.1.0 B" configuration.

In all of my preliminary experiments with both Surround Back (7.1.0 B) and Atmos Enabled Front (5.1.2) I was able to perceive sound in the upper space of the room, but NOT coming from the ceiling. Since I have no access to a theater with Atmos and no means to install top speakers I will never know if I am listening to the real thing.

At first listening the sound I am getting is pretty satisfactory, especially with my still to be finished Dolby upfiring speakers. I can listen to sounds above my TV set, and virtualization of spaces between speakers are impressive, and significantly better, when compared to, for example, 5.1 on-stage music mixing.

At this point I understand that I should not jump to conclusions as to dismiss Dolby Enabled speakers or to dismiss the efficacy of ceiling speakers.

Before Atmos I could listen to Foley effects, such as rain, off 5.1 mixings quite adequately. But now my NR737 features compulsory upmixing (Dolby Surround Upmixing), so comparisons can no longer be made.

All of the above is not restricted to Dolby Atmos. DTS:X is promising full 3D playback with the speaker layout in existence.

As enthusiasts or hobbyists we will be doing our best to experiment and find the truth. I for one who would be quite displeased to find out that all this 3D talking is just a figment of our imagination. Of course, I would like to give credit to Dolby, DTS, and Auro for what they are promising, and not tag their codecs as vapourware.

Only time and experimentation will tell if we are in the right track or not (no pun intended). A friend of mine is installing top speakers shortly. At this point I have a hope to gather some evidence as whether or not I should endeavour to do the same.