The new feature found on stereo A/V receivers is 7.1 surround sound. Stereo companies moved right on from 5.1 surround sound into 7.1 surround sound without the consumer even knowing what they need or what is best for them. It is becoming difficult to even find 5.1 surround sound receivers as the 7.1 models have begun to dominate the shelves.

Does this mean that the surround sound formats are recording and encoding everything using all of the additional speakers? Can I just add 2 speakers to my existing 5.1 setup and it will work perfectly? Would a 7.1 receiver do more for me if I only have speakers for the 5.1? Is it any better than 6.1, found briefly between 5.1 and 7.1?

I will answer all of these questions and more in the following article. I will also talk about Dolby and DTS codecs, future technologies, and disagreements in the audio community about which direction the future should bring us.

Many people are confused by why we have surround sound, when it is used, and what should they have their stereo set on to make the best use of surround sound. Those looking to buy a new stereo are bombarded by anagrams and names that are new and don't know if they need all of the features listed. 7.1 surround sound is one of those abilities that confuse consumers. And for good reason. Sound suffers from a similar problem to HDTV statistics. Often the numbers that are easy to give aren't the most important part, often it is quality that can't be put in numbers that is the most important part of the sound system. If it was possible to put a numerical value on the accuracy and value of speakers, it would help everyone (except for possibly the manufacturers and retailers). This, however, is not possible, so speakers and sound is judgeable simply by listening to what it sounds like. Since that is a very subjective way of judging value, retailers and manufacturers manage to put statistics on their sound systems that makes them appear impressive, but the value of the systems are judged in ways that are not listable.

The giant question is "is there actual 7.1 encoded music or sound available?". While the answer is yes, it is rare and only found in very specific places. Let me name most of the audio codecs which can support 7.1 encoded sounds. If your receiver does not support these surround formats (even if it is listed as a 7.1 receiver), you will not be able to listen to "true" 7.1 surround: Dolby TrueHD, Dolby Digital Plus, DTS HD (HR and MA varieties), and PCM (pulse code modulation). The two that contain the term HD are the new lossless codecs from Dolby and DTS, providing sound as close to how it was mastered in the studio as possible with the compression needed to put it on a disc. The next question is, if my receiver is capable of these audio formats and my Blu-Ray has a Dolby TrueHD or DTS HD soundtrack on it, is it automatically in 7.1? The flat answer to this is no. Very few soundtracks are put in 7.1, most Dolby TrueHD and DTS HD soundtracks are limited to 5.1 sound. I know of about 75 movies out of approximately 2000 Blu-Rays which have 7.1 soundtracks, and the movie names are not ones you would rush out to buy. As of this date, 2/22/2010, the most popular movies with 7.1 soundtracks (in my view) are: Gamer, Crank 2, Ice Age, 3:10 to Yuma, House of 1,000 Corpses, Rush Hour 3, Snow White and the Seven Dwarfs, Hellboy II, Rambo, the Running Man, Saw IV, V, and VI, Semi-Pro, Star Treks II, IV, and VI, Transporter 3, and W.  This is a very unimpressive list of movies in which they paid extra money to have the sound mastered in 7.1.

I refered earlier to "true" surround sound. There are formats such as Pro Logic which can take a stereo or 5.1 recording and create a 7.1 sound out of them. Earlier Pro Logic codecs could transform stereo 2-channel sounds into 5.1 surround sound. This I refer to as "fake" surround sound, for it is just a processing technique which makes sounds out of unused speakers. While these techniques do a remarkably good job "faking" the sounds, there is no authenticity to the surround speakers and rear speakers sounds.

When changing from 5.1 surround to 7.1 surround, can you just add two speakers to the rear and it works? The answer to this question depends more on the placement of the surround speakers. Surround speakers refer to the two channels behind the listener in a 5.1 layout. Rear speakers refer to the 6th and 7th speakers that come with 7.1 surround. Optimal speaker placement in a 7.1 setup would have the surround channels slightly behind the immediate right and left of the listener, at between 90 and 110 degrees to the listener. The rear channels should be behind the listener at between 135 and 155 degrees. If the original surround channels of the 5.1 speaker placements were to the left and right, then yes, the rear channels just need to be added behind the listener. If, however, the original surround speaker locations were more behind the listener, as I often find them to be, then it becomes more difficult to add the rear channels.

 So far it sounds as if a 7.1 receiver will not help most people. There are, however, additional reasons to get a 7.1 receiver. Many people are now adding speakers elsewhere in the house, be it a bedroom, kitchen, or outdoors. Old receivers had a A/B channel selector, but needed a single amp in order to push the A & B speakers simultaneously and often couldn't keep the volume up in the process. Now, with 7.1 receivers, manufacturers are including two amps inside the same system, the main amp pushing the front 5.1 surround channels, the second amp pushing the 6 and 7 speakers. These receivers also now include a second zone, as opposed to the old A/B channels. The second zone can play a different input then the main zone, allowing people to watch surround sound in the main listening location and the same or something different such as the radio outside or wherever the second set of speakers are located. Therefore, a 7.1 receiver can be useful even if only a 5.1 speaker setup is used in the main location.

Is 6.1, a format used breifly between 5.1 and 7.1, still useful? Not really, since mastering of 6.1 has only been used about 30 times, and only a few movies in 2009 was it still used. I expect in 2010, all Dolby TrueHD and DTS HD mastering will be done in either 5.1 or 7.1, but 6.1 will fall by the wayside.

What will be found in the future is a matter of debate among audiophiles. There are now receivers that have 7.2 sound. This is in reaction to a sound problem with LFE (low frequency effects) in which the subwoofer's sound can cancel itself out in some locations. This is refered to as "standing waves", when the bass sounds bounce off a wall and come back to cancel out the same effect in a certain location. A second subwoofer often causes this to go away. Other receivers are coming out utilizing 9.2 surround sound. This is a new system which resulted from some audiophile's reaction to having more speakers behind the listener than in front. The 8th and 9th speakers are called "presence" speakers and are located above the right and left channels, but significantly higher on the wall. The idea is that our auditory senses are much better for sounds in front of us than behind, and giving a sense of height to the sounds in front of you is a much more immersive field. Whether or not the 9.2 sound will be mastered onto the audio of discs in the future is yet to be seen, but the idea is a good one. Where our future speakers beyond 7.1 will be located is a continuing discussion in the audiophile community, and I know of no prevailing opinion on the subject.

Where the future will take us is definitely yet to be seen, but 7.1 surround sound has certainly rooted itself in the stores and will have to be used more in the future than it is currently being implemented at present.