These Go to Eleven

As you probably already know, Dolby’s ProLogic IIz audio decoding process adds height channels to the surround sound experience in a 5.1 or 7.1 home theater. Not to be outdone, competitors DTS and Audyssey have developed their own formats that bring us up to 11.1 channels of sound. The question I have is: Do we really need this many speakers, and where will we put them?

To this day, the majority of home theater systems (and theatrical venues, for that matter) are configured in a standard 5.1 layout with three speakers across the front soundstage, two surrounds, and a subwoofer. Most movie soundtracks are mixed this way as well.

A number of years back, A/V receiver manufacturers started adding support for two additional channels, called the Surround Back Left and Right, in between the main surrounds. This helps to fill the gap in the rear soundstage, especially in large listening environments. Audio decoding processes (most notably Dolby ProLogic IIx) were developed that could extract sound cues from the other surround channels and matrix them into the Surround Back channels. The Blu-ray format also includes support for discrete 7.1 sound mixes, though these are still relatively rare.

The home theater environment actually leads the way in developments like this. Discrete 7.1 audio has existed on Blu-ray longer than it has in movie theaters. The Dolby Surround 7.1 format was only recently introduced to theaters last year. ‘Toy Story 3’ was the first movie to support it.

Likewise, height channels made their first appearance in the home, not in professional theaters. Dolby ProLogic IIz can be applied to either a standard 5.1 system or a 7.1 system to add additional height speakers above the front Left and Right. I admit that I was skeptical of the benefits of this (we still have no movies natively mixed with height channels in mind), but I found a demonstration at Dolby Headquarters last November to be surprisingly impressive. In the clips we watched (‘I Am Legend‘ was the primary movie demo), the added channels genuinely helped to expand the soundstage without sounding gimmicky. I still do not personally use height channels in my own home theater, but I’m no longer opposed to the idea.

And now DTS Neo:X and Audyssey DSX give us 11.1 sound. What does that entail? These formats start with a 7.1 configuration and then add two height channels and two new width channels on the sides of the room. The purpose of this is to fill the gap between the front and rear soundstages, under the presumption that there’s currently an audio “hole” there. Again, I admit to some skepticism as to the necessity of this. However, I haven’t heard it demonstrated yet.

My feeling is that this will only be useful in particularly large home theater rooms. I can tell you that in my own HT room, I don’t currently feel that there’s anything missing from the surround sound experience by not having speakers on the sides.

On the other hand, when I spoke to Craig Eggers, a VP at Dolby, a few weeks after my trip to that company’s facility, we had a talk about 5.1 vs. 7.1. I made the argument that 7.1 may not serve much useful purpose in a small home theater room, where there isn’t much of a gap between the main surround channels. Craig then made a case that 7.1 is always useful, even in this type of space. Perhaps these new width channels will be the same way? We may not particularly realize that anything is missing until we actually put speakers there and hear the difference.

Nonetheless, I think that speaker placement is going to be a real issue in most home theaters. I know that I’d simply have no place to put these width channels in my room. I suspect that a lot of people are going to run into that problem.

[via CEPro]


  1. Extra width channels really only makes sense in a long room. Mine is rectangle, but because of windows and other stuff, my tv is on one of the long walls, and the couch on the other. I do not have room to add a couple of extra width speakers. I am thinking about going 7.1, and my system supports (ie – have to plug them into another amp, which i have, and its not being used) either height or additional surround. Wish I could go both. Height would certainly be easier, but I am sure the surrounds would be more immersive.

    Something I have always wondered about is the possibility of more height speakers – specifically floor and ceiling. Floor may be overkill, but ceiling speakers would be cool, and would allow for some really immersive sounds when dealing with rain, wind, storms, explosions, and bullets whizing around the sound field.

    Yeah, there is deffinately an “audio hole” on the sides, but I seriously doubt many people are going to have the room (or an understanding-enough spouse) for the extra speakers.

  2. hurin

    You’re really much better off if you buy a decent stereo system than a bad 11.1.

    And if you’re unsatisfied with the sound of your setup, it’s usually a better idea to improve acoustics than it is to buy more speakers. You’ll be amazed at the difference a thick rug and a large sofa can do.

  3. Most people don’t even have a receiver much less 5.1 audio. I’ve had 5.1 audio since the mid 90’s and my Dad set it up in the 80’s when only certain VHS tapes had the ability to do any surround audio.

    As far as I’m aware the number of DVD’s and Blu-Rays that support more then 5.1 audio is pretty slim. So your definitely better off spending the money on the quality of your speakers over the amount of them. Second to that is the actual receiver you use to send that audio to the speakers.

  4. It’s getting to the point where the only place you can have a home theater set up is in a fully enclosed box of a room. Placing 11 speakers would be hell in anything other than a completely enclosed room.

  5. Eric

    Foe those of us that live in apartments, space is of secondary concern to volume increases brought on by additional speakers. I hate not being able to crank a movie with amazing sound, but it seems that the more speakers you run, the more pronounced you need your center channel in a lot of films just to hear dialogue clearly. This can cause major issues if you are not a homeowner.

  6. Stacey Nash

    I would love to have 7.1 speakers set up, but the walls in my living room do not allow me to do this. I do have a 7.1 reciever, but it’s just not going to happen. I have a feeling this applies to most people. I personally think the only way I could to do this would be to build an actual theatre room. This will happen one day, just not in the house I live in now! In the meantime, 5.1 uncompressed audio is working just fine for me right now!

  7. i just noticed this on my pioneer HD sound system and i love it.i have these small speakers and i have them on top of two bookcases on each side of the room and it does add to the movie you can hear the surrounds better.

  8. MNMan

    Hey, I got to hear the demo of the DTS Neo:X at the Vegas electronic’s show, and my skepticism turned to excitement pretty quickly. While I am aware that they of course selected the best possible clips, the clips they showed us were insane. The audio sound stage they created with the extra two “wide” front speakers was almost unbelievable. They took a 12 or so foot wide room and made it sound like it was fifty feet wide. They played a scene from Secretariat where the horse runs across the front sound stage and it sounded like the horse ran from outside the room, across the front and then out through the opposite wall. It was fantastic. Since the room was a realistic size, 12 x 18 or so, I thought the sound stage the 11.2 setup they were using (two subs) was most impressive by how enormous it made the room sound. (Same thing with “height” front speakers, they played a clip of a helicopter that sounded like it came through the convention center roof and then hovered above the screen.) I was totally sold and have been impatiently waiting for a receiver to come out with the DTS Neo:X feature (the floor model they were using was an Onkyo, so I am thinking they will be the first to offer it). They told me Q2 at the show, but I have not seen anything yet…