Home Theatre PC Motherboard Shootout

Audio Performance

The audio performance tests were done using Audio Rightmark 6.0.5 and a 3.5mm gold plated, oxygen free stereo loop back cable between stereo out and microphone input. Results were taken at the DVD sample rate of 16-bit/48KHz and High Definition 24-bit/96KHz.

What we're looking for:

• Noise Level: A higher negative is better. This is usually viewed in relation to a signal level which provides a signal to noise ratio. As you get closer to zero there's more noise and lesser audio fidelity.
  
• Frequency Response: Two values listing how close to the lower higher frequencies the codec can reach. If it hits them perfectly it'll display a 0, 0.
  
• Dynamic Range: The difference between the loudest and quietest sounds the codec can make before it distorts them. The larger the gap, the better.
  
• THD and IMD percentage: Closer to zero is better. THD and IMD are best looked at together, where as if you have a lot of THD and not much IMD, then it'll offer a warmer accurate sound. High THD and IMD provides a warm, inaccurate sound, low THD and high IMD gives a cold inaccurate sound and finally low THD and IMD gives a cold accurate sound.
  
• IMD = intermodulation distortion and is a fancy way of saying conversion interpolation, which is a basic detection of the quality loss after an analogue to digital then digital to analogue conversion. By comparing it to a highly compressed source it shows up problems with the codec and converters.
  
• THD = total harmonic distortion, which shows up unwanted harmonics; integer multiples of the original component sound that can be second, third, fourth degrees or overtones for example.
  
• Stereo Crosstalk: where the stereo channels "talk" to each other and interact. Ideally you want them entirely separate, unmixed or echoed in either channel, so a higher negative a result as possible is preferred.

16-bit / 48KHz

24-bit / 96KHz

The results are as we'd expect – the Realtek ALC883 on the Asus is pretty poor, while the Realtek ALC889a on the Gigabyte is at the other end of the scale somewhere towards awesome. Finally, the Realtek ALC888 on the MSI is somewhere in between the two. No matter how much we tried to arrange the input and outputs for all the motherboards, in all the graphs the green line representing the Gigabyte is clearly better in both standard and high definition.

For the cost, both the MSI and Gigabyte provide exceptional value on this front – no longer are the most inexpensive boards subject to only the bottom run of components. The Asus board is disappointing to say the least – the audio is certainly adequate and many might never tell the difference if all you playback is compressed audio, but a dedicated soundcard will definitely offer an improvement over what’s included, but it will also increase the total cost to what is already the most expensive option here.