Do or Don’t: Dolby Atmos for home theatre

Written by Published | Rapallo AV Team

It’s been a little while now since Dolby Atmos quietly made its entrance in the world of cinema. The Hobbit and Gravity were one of the first movies with an Atmos soundtrack and a lot has happened since.

A few years on and Dolby Atmos has become the ‘it’ word for home theatres too. A decent range of Av receivers and Pre-amps are now able to decode Atmos including Onkyo, Pioneer, Sony and Yamaha.

Atmos Elevation (or Atmos -enabled) speakers – although a bit more slowly – are starting to enter the market as well.

But how much is hype and gimmicky and how far do you really want to go to get the ultimate sound experience at home?

 

To quickly refresh your memory: Dolby Atmos is an object-based surround sound format that gives more freedom to direct sounds to specific locations instead of being restricted to the common channels we’ve come to know in home theatre. One of those locations is overhead, which requires the addition of either in-ceiling speakers or use of special Atmos elevated speakers (basically speakers with additional drivers that direct the sound upward to reflect off your ceiling).

 

To start off we would like to point out that there are some pretty cool things about Dolby Atmos:

Dolby Atmos is as we mentioned object-based. Unlike the traditional Dolby TrueHD fixed surround sound, it is scalable to all speaker lay-outs; be it 5.1 or 7.1, the whole 64 channels of the professional cinema or the 32 channels at home.

For filmmakers this means that during the production of a movie only 1 track has to be mixed for all speaker lay-outs as opposed to several separate ones for all sorts of different lay-outs. This is cutting a lot of cost in the production process, which can only be a good thing for the movie world.

 

But how much sense does it make to introduce Dolby Atmos to your home theatre?

 

Upgrading to the Dolby Atmos format for home theatre from your 5.1 or 7.1 speaker system requires adding either 2 or 4 speakers.

 

We line up the Dolby Atmos speaker options for the home theatre:

  • 5.1.2: A standard 5.1 setup with a pair of “middle” in-ceiling speakers.
  • 5.1.4: A standard 5.1 setup with front and rear pairs of in-ceiling speakers.
  • 7.1.2: A standard 7.1 setup with a pair of “middle” in-ceiling speakers.
  • 7.1.4: A standard 7.1 setup with front and rear pairs of in-ceiling speakers.

 

The whole additional in-ceiling Atmos speaker set-up is not as straightforward as it sounds though. As mentioned before, unless your home theatre is very, very recent, it is unlikely that you pre-wired for the additional in-ceiling speakers required for Atmos, making this option a costly nightmare in a lot of situations.

 

To address this, Dolby introduced the Atmos Elevation (or Atmos-enabled) speaker option.  But again, this is really only viable if you have flat reflective ceilings and your ceiling height is under 4.20 meters.  If you have higher vaulted ceilings or you have an acoustically treated room with absorption on your ceilings, you won’t be able to use the Atmos Elevation speakers.

I guess it’s fair to say that both options have potential hick ups and neither is going to be cheap.

 

There are also some ‘buts’ to consider in regards to the plain physics of the whole Atmos Elevation speaker idea:

Firstly, the speaker driver is recessed into the baffle, which will have issues with diffraction that need to be addressed.  The use of absorptive foam inserts or angled sidewalls goes some way to deal with the diffraction.

Pioneer for instance integrates the Atmos driver into the cabinet that is sold as one unit.  The driver is flush mounted into a 20 degree angled baffle instead of recessed, which addresses our concerns about diffraction.

Secondly, we also wonder how the added mechanical vibrations from a separate speaker integrated into a shared cabinet will affect the overall sound quality of the main or rear channels.

 

It is noteworthy that in addition to integrated solutions, some manufacturers like Definitive Technology and Onkyo are offering Atmos speaker add-on modules to place on-top of your current front and/or rear speakers. It is by no means a cheap option though and we wonder whether the Dolby licensing has something to do with that.

 

On a final note regarding the in-ceiling vs the Dolby Elevation speaker debate, it is good to be aware of the vested interest Dolby has in licensing this speaker technology to its partners. While Dolby themselves claim the Dolby Elevation speakers are a better solution than discrete ceiling mounted speakers, conversely, they don’t have a licensing solution for in-ceiling speakers.

 

In summary, it looks like the market is about to be flooded with Dolby Atmos related gear. To take advantage of the new format, you will need to make a significant investment: in addition to new or additional speakers, you will also need to purchase a new av receiver (blu-ray player and HDMI cables don’t need to be replaced).

Whether it is for you personally a good idea to go down the Dolby Atmos path depends largely on your personal situation and your preferences.

With over 90% of home theatre fans not having the luxury of a separate dedicated home theatre room one could argue that it is probably better to have a well laid out and correctly done 5.1 set-up.

On the other hand, if you are one of the lucky ones to have a dedicated home theatre room with a bit of spare cash at hand, you may have found your next project.

 

 

Sources: Dolby, SVS, Klipsch, Elac, Audioholics, WhatHifi, Cnet, Trusted Reviews