Of course, we cannot test every sound card out there. We have a list of cards that we know work well, but this list is certainly incomplete.
Note that if you're outputting digital MPX (newer transmitters often support that), it really doesn't matter which sound card you use, because there's no quality difference between digital signals.
The most important 'feature' that a sound card must have to be able to use it for MPX output is that the frequency response must be as flat as possible between 0 Hz and 60 kHz. Flatness at the low end is the most important part, because if it's not flat on the low end that can cause overshoots. Stereo Tool can compensate deviations on either end of the spectrum, and once calibrated, there isn't really much difference between a calibrated sound card and one that's really flat, but setting it up requires a bit more work.
PCIe sound cards
PCIe sound cards can give you the lowest latency. The following are known to work well:
- Any Marian card (see https://marian.de/)
- The AudioScience ASI5810, 5811, 5812
- ESI Juli@, which is no longer produced, requires a bit of low frequency tilt correction
USB sound cards
Raspberry Pi sound cards
- All HifiBerry sound cards (DAC+, DAC+ Pro, DAC+ADC, DAC+ADC Pro)
There are many cards that we have not tested but will probably work well. Also, many Realtek on-board sound cards work pretty well (although they tend to have a higher noise level), but for those it really depends on how the motherboard manufacturer has integrated it. You almost always need to use tilt calibration for the low frequencies, but that depends completely on the motherboard manufacturer.
If you have a sound card that requires calibration, follow this video: https://www.youtube.com/watch?v=vNX2Y1c-uDg