Sound

The sound card is responsible for the audio output that is heard through the computer. Most sounds that we hear are continuous, like a train whistle, which are analog. This diagram shows how analog sounds are converted to digital sounds.

Computers convert everything into numbers, and music is no exception. As the sound comes down the wire the computer measures it and stores it in a file. Computers are digital, so the sounds are not continuous. Rather, they are digital replicas of real-world sounds. When it is time to play back the music, the measurements are looked analyzed and the sound is recreated. Sampling is the technique used to convert sounds into a digital form. The sound is stored in a file and later played back at the same rate, replicating the real world sounds that we hear.

MIDI

MIDI Musicians use a computer to record their finger action instead of recording their actual sounds. The actions recorded are what notes are being played, at what time, in what order, and for how long. A MIDI file's resulting output is like a computerized music sheet. The computer plays back the sound rather than the finger action. When the computer reads the file back, it plays each note in the right order and at the right volume.

What Do Those Numbers Mean?

For sound cards, the number that is presented on the card itself is the number of different voices, or sounds, that the card is able to produce. The higher the number, the higher the varieties of voices that can be produced. For example, if the sound card is 16 bit, it can represent 16 different voices that can be heard. If the sound card is 32 bit, the number of different sounds is 32. People are mislead into believing that the bit representation of the sound card refers to bit resolution, whereas the bit actually means the number of different voices that can be represented.

Sound cards are also physically located on the motherboard on one of the PCI slots along side the video card. There are many different types of sound cards available. For more information about the specifics of the different cards, as well as the different price ranges, see the listed references below.

Video

The video card is the hardware responsible for displaying output on the monitor of the computer. Most, if not all, programs have a visual output that needs to be displayed. The video card takes the output and tells the monitor which dots on the screen to light up, and with what color. When a program needs to display an image, it sends a message to the video card. The video card responds, and pieces the right picture together. It is then sent to the monitor. The video card and the monitor are the crucial components required for quality images to be displayed. Poor quality video cards can cause fatigue and eyestrain, due to the fact that they do not support a high refresh rate.

Performance

For some applications, the performance of the video card will not have a significant effect, but for the others it is the basis of performance. For video games, video cards are highly significant in performance. Some video games require a high frame rate for smooth animation and better quality graphics. Graphics programs and video games require certain support for them to run at their full potential. Some three-dimensional graphics will not run on a video card that does not support it.

Video Memory

The term video memory refers to memory chips that are located on the video card itself. This seperate memory is needed, and used, for better quality graphics. The more memory there is, the higher the resolution the card can display. Choosing the wrong video card can cause systematic problems. Some cards have unstable drivers that can cause difficulties with the computer.

Location

The video card is physically located on the motherboard, and is also connected to one of the PCI slots. Video cards are constantly being improved, which allows the graphics quality that is displayed on the monitor to become better and better. An accelerated video card has a special chip on the card itself that helps display images and graphics faster on the monitor.

Before purchasing any video game, be sure to check the video card requirements. If the requirements are not met, the game will not be able to be played to its full potential, or sometimes not at all.

Tom's Hardware Guide For video card and sound card price guides and more detailed information. http://www.tomshardware.com The PC Guide For more information on video and sound cards. http://www.pcguide.com/