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Sound Advice

Like many things in life, choosing a sound card is more complicated than it used to be. This is not necessarily a bad thing because it means we have more choices, and our computers can do things with sound that were barely dreamed of 20 years ago.

Originally, if we wanted to add external speakers we would buy a sound card (usually stereo but not always) and plug it into a spare ISA slot. When PCI came along we could choose between an old 16-bit card or a modern 32-bit card, and either of them provided the same three connectors: a Speaker jack, Microphone input, and Line In for all other input sources. Very rarely you might see a DIN-5 in/out for a MIDI keyboard. Today, even some low-end sound cards under $20 can provide Dolby digital surround sound, and the feature list gets longer as the price goes up.

Before trying to select a sound card it is necessary to identify your needs in that area. This can range from a word processor or other office use where no sound is required at all, to home entertainment or professional sound editing. Sound editing is a specialized area whose practitioners probably know more already than we can provide in this tech tip, and office systems in almost all cases can get by with the sound circuitry built into the motherboard, so we are going to focus on entertainment.

Games and DVD movies are the two big areas where the computer is used for home entertainment. Both of these uses are growing rapidly and attracting more manufacturers, who are forced to innovate to compete with each other. This is great for the consumer, but as I said at the beginning, it complicates choosing a card. Here are some of the technologies to consider:

DS3D - DirectX Sound 3D is a "primitive" method of emulating 3D surround but has recently improved considerably. Microsoft's DirectX Sound 3D offers a range of commands to place a sound in 3D space, in a technique known as positional audio. In a nutshell, DS3D manipulates the characteristic of sounds to make them seem to come from a specific direction, such as from behind or from the left, and to give the impression that you have more than 2 speakers. Originally this was all done through the CPU and required significant processing power. It was not until DirectX 5 that Microsoft allowed DS3D to be accelerated by third party hardware, reducing the stress on the main system CPU.

A3D - Aureal 3D was originally developed in 1997 in collaboration with NASA (National Aeronautics and Space Administration) for use in flight simulators. Aureal's A3D technology was another 3D emulation, and like Microsoft's DS3D it relied entirely on the CPU's processing power until recently but now allows hardware acceleration. Newer versions also have a resource manager that allows game developers to manipulate Aureal's 3D algorithms in ways that can simulate different atmospheric environments, such as thick fog or underwater.

EAX - Environmental Audio Extensions was first introduced by Creative Technology's SoundBlaster Live! Sound cards in 1998. EAX began as a simple way to add reverberation to DS3D. In 1999, EAX 2.0 enabled the creation of more compelling and realistic environments, such as simulation of the muffling effects of partitions between environments (such as walls) and obstacles within environments (such as furniture). This was possible by adding the obstructing feature into the algorithm as its own audio source.

Dolby Digital - Newer sound cards today allow Dolby Digital sound to be passed directly through the card's hardware and be decoded to 5 separate channels. This can be further enhanced with circuitry on the sound card. A Dolby 5.1 surround sound card supports decoding through its onboard processor into six discreet channels. These channels are: front-left, front-right, front-center, rear-left, rear-right, and the sub-woofer (for the .1). And this has continued to evolve. For instance, Dolby 6.1 added a center-middle channel and 7.1 added 2 channels, center left and center right.

Speakers - For the longest time computer speakers were taken for granted. While speakers for the stereo system were chosen with great care, just about any old speaker (or pair of speakers) would do for the PC. This made complete sense until recently, because the sound quality coming out of the computer could not take advantage of better speaker quality anyway. Now with Dolby Digital 6.1, speaker quality and quantity make all the difference.

Planning - The key in a good realistic surround system is sound separation, which means multiple speakers in the right location. This requires planning, but with recent technology it doesn't have to cost an arm and a leg. Decent quality speaker systems for Dolby 5.1 and 6.1 speaker system are now available for less than $50 from well known manufacturers like Creative, Labtech, Advent, and Logitech, to name a few.

So, what does all this high-tech sound capability actually mean in your everyday life? Can you actually mount speakers behind your computer chair? Since the key to surround sound is channel separation, it's really pointless to have 5 satellite speakers all standing next to each other because of the limited space you have on your computer table. And do you really want to install a 200-watt subwoofer that'll shake your whole house when you're playing Halo? Some do, some don't.

So, rather than barging into your local computer store and getting overwhelmed with all the choices for audio upgrading, do a little planning first. Determine your needs, your budget and the space available, and you'll find you are dealing with a much more manageable set of choices.

Disclaimer - The Micro 2000 Tech Tip is a free service providing information only. While we use reasonable care to see that this information is correct, we do not guarantee it for accuracy, completeness or fitness for a particular purpose. Micro 2000, Inc. shall not be liable for damages of any kind in connection with the use or misuse of this information.