The most obvious solution for achieving high quality sound from your PC is to simply fit a high quality sound card, but there can be a number of things going on in the background which could scupper your success.

Internal electronic noise aside, audio enthusiasts have long known about the many nasty things which can happen to your precious bits on their way through Windows and out of your sound card’s SPD/IF. Windows XP’s Kernel Mixer would take the sounds from all applications and up-sample them into a single 48KHz stream, thereby hobbling CD audio’s 44.1KHz originals. The situation is improved with Vista, but your sound card may still not be outputting unmodified 44.1KHz digital audio.

Luckily there are ways to bypass XP’s Kernel Mixer. These typically involve ASIO (Audio Stream Input / Output) or Kernel Streaming, usually operating as plug-ins for popular media players. Beware they may not work with your specific sound chipset though, and even then some audio components or their software still implement additional naughty conversions without you realising. Like many hardware tweaks, it may involve some experimenting to find a combination that delivers good quality – and works reliably.

I was contacted by Steve Monks who wrote to explain how upon discovering the disappointing effects of Kernel Mixing he tried out a Kernel Streaming plug-in for Winamp which avoided the process and greatly improved the sound quality. The plug-in however proved unstable at times, so as a programmer, Steve asked permission from the original author to take a look at the code and post a revised edition. Following further requests, he rewrote the plug-in which you can find here.

The final part of the equation for Steve was swapping his Aureon Fun 5.1 sound card for an M-Audio Audiophile 2496 PCI card. He now reckons the sound is essentially as good as his other audiophile components.

Despite being several years old, the Audiophile 2496 continues to receive good reports from enthusiasts, and while stocks last they’re also available at affordable prices around $100 USD. As luck would have it, I also happened to have one of my own from an older project, so decided to dust it down and implement Steve’s plug-in on my own Windows XP-based media PC.

First I tried the on-board Realtek audio chipset with an optical SPD/IF connection to my DAC (there was no coaxial option on the board). Music played through Winamp using the default configuration was really quite flat and uninvolving. Switching to the M-Audio Audiophile 2496 and a coaxial connection to the DAC greatly improved the imaging and dynamics, but it was still far from a decent Hifi transport. Installing and selecting Steve’s Kernel Streaming plug-in however transformed the quality. The sound-stage became wider, imaging more precise and details more apparent.

This was a decent upgrade and a great result for both the card and software. If you want to use an XP-based PC as a Hifi front-end, I can highly recommend picking up an Audiophile 2496 card and driving it with Winamp and Steve’s plug-in. What makes it so good for Hifi audio though can result in some operational caveats with other applications which may rule it out for your system.

M-Audio’s Delta cards cunningly bypass the mucking-about of Windows’ kernel mixer and therefore aren’t affected by the standard Windows Volume control. Instead, to control the volume of the card’s analogue outputs, you’ll need to go into the dedicated M-Audio Delta Control panel and adjust it there instead. This may not sound like a big deal, but it can prove inconvenient for some applications.

Windows Media Center Edition 2005 for instance, uses the Windows volume control system, so if you install the AP2496, you won’t be able to adjust the volume using the standard remote control or IR keyboard’s buttons – the volume will be fixed, and MCE somewhat unhelpfully displays ‘Mute’ where the slider used to appear. I did however find the remote volume control worked fine in Media Player Classic, which many enthusiasts use to play MKV files amongst others. Anyone considering the AP2496 should also know there’s more appropriate choices for gaming, and that 64-bit Vista drivers are currently in beta form only.

Ultimately you can use an AP2496 successfully in a system running MCE, but for the greatest operational convenience and quality you’ll need to set the Control Panel volume to its maximum and adjust the overall volume from an external pre-amplifier / receiver / audio processor using its controls.

Gordon's other hardware configurations for great sound quality!

The streaming appliance: a Logitech Squeezebox with some neat modifications.

The ultimate solution: the small but perfectly-formed Benchmark DAC1 PRE.