You know what I think? I think that people should start to consider mobo designs in which there is any unacceptable background noise at all in the onboard sound,
broken and unacceptable. And hardware sites (like this one), should really bag on mobo makers if the onboard sound (or LAN) is of unacceptable quality. I'm of the school of thought, that if you intend to do something, it should be done well (or at least minimally - it should be done acceptably), or it shouldn't be done at all. What is the point of including
defective integrated sound? What real purpose does it serve, other that to simply satisfy a marketing bullet-point on the box, and create the appearance of being competitive with other mobos, when in fact, bad onboard sound is as useless as no onboard sound. Why should people pay for broken hardware? It doesn't make sense to me. I long for the days of yore, when mobos had
tons of slots, and
no "worthless" (cheap, shoddy) integrated hardware. The sad thing is, at least back in the i440BX days, some of the OEM mobos with integrated Crystal, Yamaha, or Creative audio - it sounded GOOD. So what is the problem these days? Mobos are fancier, have more features, are more complex, and cost more too. And yet,
they often sound worse! They had the same sorts of analog audio problems, that the ancient low-budget 8-bit SoundBlaster ISA cheapo knockoffs had! Welcome back to 1998.
Edit: Additionally, one possible solution to implement some analog shielding/spacing, would be to use a riser card or a small, seperate PCB, containing the analog audio portion of the circuitry. Since it would generally need to be connected to the audio jacks located on the ATX I/O plate, then the PCB should be located somewhere near there. Even better would be to make it semi-modular, as often, the "controller" for the codec is located on the system chipset, and communicates digitally over a serial link to the "AC'97 CODEC", which then has analog audio connections on it. So slap the AC'97 onto that daughterboard, perhaps some caps/filters, and wire it to the ATX I/O analog sound connectors, and to the system chipset. If it were modular (and with the versajack/anyjack/etc. technology this would be really easy), then you could take the included 5.1 audio solution off of your older mobo, and drop-in a higher-end module like a 7.1 or 24-bit solution.
Now that I think about it, there's really not a lot of difference between the AMR/CNR/etc. slots in terms of a mini-card containing just a codec and maybe an amp circuit, except that the AMR slot is generally on the wrong part of the board, on the farthest slot from the ATX I/O bracket. If it were the nearest, then it might work out. I don't think that you would even need a connector of that size though, a smaller header-style connector on the mobo would do just fine, kind of like how the Creative WaveBlaster daughterboards connected to sound cards back in the day.
PS. The Vortex2 cards absolutely ROCK. Best 4-channel PCI sound card ever made, IMHO.