Tech--for Everyone: What Do The Dolby Numbers Mean?

Dolby 7.1 Must Be Newer Than 5.1, But Is It Better?

A reader wrote and asked me for some advice regarding a sound card.

Q: Paul -- My son has been pestering me to buy an Audigy sound for his computer. He is very much involved in some kind of online gaming world and he says he needs this for better results. I have asked him to explain to me how this Audigy will make things better, but all I have been able to really grasp is that the item he wants is "Dolby 7.1".

I am reluctant to purchase this additional item as only two Christmases ago Santa took special pains to make sure that my son's computer could play all the latest games. I have checked, and his PC has Dolby 5.1.

Can you tell me why my son thinks he needs Dolby 7.1 to play today's games?

A: First of all, a disclaimer: I am be no means an audiophile. I will do my best to provide a solid computer geek answer, (but I will also ask my more knowledgeable readers to assist and/or correct me) but I won't dare get involved in parenting advice. I'll try to be brief.

Audigy is a model name (a family of products) of Creative Labs-- a company practically synonymous with computer sound cards .. and it's the company responsible for me becoming a tech, as they forced me to learn about IRQ's and memory address spaces .. back in the early days.

Dolby is a audio format known for "noise" reduction, compression, and the ability to separate out discrete "channels", which gives us the ability to create "surround sound" environments. It is this latter where the numbers come in.

The numbers represent the number of "channels" available. A "5.1" is a six channel ability and a 7.1 is an eight channel. The first number is 'normal' channels and the 1 is for a special, bass-heavy "sub-woofer" (designed to add psychological effect to thunder, and .. explosions).

The "channels" are usually assigned an area -- center, left front, right front, left rear, and right rear, and are intended to go to corresponding speakers. A "5.1" configuration is shown here.

In gaming, this can aid the player when audible clues are provided by the game designers.. for instance, stealthy footsteps may be sent to the left rear speaker, but not to any of the other speakers, and this could alert the player that an enemy is behind him (and to the left)... and it will probably be his only clue, before the enemy strikes.

A "7.1 configuration" allows the addition of two more speakers, as shown below.

What should be obvious now is that you need speakers (6, or 8) physically placed to take advantage of these "channels". If all you have is two rinky-dink little PC speakers that came free with your system, or built into your monitor.. well, you really aren't going to notice any difference between plain old stereo, 5.1, or 7.1 .. so you need..

.. as I have written and explained to Santa a few times now.

Okay, maybe you won't need an ultra-deluxe get-up like the GigaWorks, but you will need a really high-quality set of headphones, and/or a multi-speaker + sub-woofer speaker set.. and you'll need 7 normal + 1 sub-woofer to make an upgrade from 5.1 to 7.1 really pay off.

Perhaps, instead of a new card, you might consider, instead, a "gaming speaker" setup to take full advantage of the 5.1 you have, like the Logitech G51 Surround set.

Today's free link: for those who found my explanation of Dolby inadequate or confusing, click here for the Wikipedia page which describes Hertz and "lossy" and junk like that much better than I did.

post to jaanix

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