Sound cards

Staff Writers (PC World) on 22 June, 2005 11:26

While the benefits of running a top-quality video card and monitor are obvious to most consumers, the advantages of shelling out for a high-end sound card can be a little more nebulous. Be it listening to MP3s, recording music, or playing games, there's a soundcard for every application. This buying guide will explain to you the relevant soundcard technology, specs and must-know facts, ensuring, you make the right purchase decision.

Integrated Sound

These days, just about every modern PC ships with some basic form of audio output integrated into the system. Audio processors have been widespread on motherboards since the mid 90s, and there's a good chance that the machine you're using now is relying on an integrated audio controller to output sounds. Integrated controllers are widely employed because they're relatively inexpensive to add to a motherboard and suffice for less-discerning users. Generally, the sound provided by these processors is adequate for system alerts or use in an office environment, but falls down for serious gaming, music or DVD playback for a couple of reasons.

Motherboard with onboard sound

The first is sound quality. While current integrated solutions offer impressive integrated sound on paper, the audio processors and associated wiring are built into the motherboard. As motherboards feature thousands of wires packed very close together, the current flowing down one wire often affects the current flowing down another. As a result, interference is common, which shows up as background noise in the audio signal. This tends to mean lots of pops, clicks, and buzzing can appear in output sound. The balance of signal and background noise is quoted as a signal to noise ratio (SNR), which is measured in decibels (dB). If a motherboard features a high signal to noise ratio. of around 100dB) , the listener can expect a clean, clear signal devoid of any background pops, clicks or buzzing. A low signal to noise ratio (below 90dB) will mean that audio signal will be affected by interference.

PCs that have motherboards based on the Intel 915/925, Intel 945/955 and NVIDIA nForce4 chipsets, for example, all have exceptional sound capabilities using the Realtek ALC850 codec (coder/decoder). This codec supports up to eight speaker channels, up to 16-bit resolution and has a signal to noise ratio of 100dB (decibels), which means the chip does not produce a lot of background noise that can colour the audio signal. Motherboards with this chip can be used comfortably for audio creation and editing.

Some older motherboards and some that are geared towards the entry-level market feature audio chips from C-Media, which can have signal-to-noise ratios below 90dB, and may not be suitable for those of you who want to work intensely with audio.

The second reason you may not want to use an integrated sound controller is the fact that they rely on the CPU to process the sound, which can slow a system down slightly. This isn't a concern for most users as the CPU impact is extremely small, but serious gamers and video editors want to keep the processor as free as possible to ensure all system resources are allocated to driving software.