Besides the little bit of hardware in a SDR nothing is more critical than the sound card. The sound card converts the incoming signals in to a form that the computer can process.

How good a card determines how well your radio can hear weak signals in the noise and how sensitive your radio is. So what is recommended?

Generally these factors improve the operation of your SoftRock or other SDR radio.

Number of bits
Dynamic range
Resolution
Frequency response
Sampling rates available

Needless to say sound card manufacturers are related to used car salesmen, in other words they have no qualms about outright lying or misleading you when it comes to information about their sound cards. So lets look at the qualities of a sound card that are desirable, they may not exactly meet the demands of the average consumer so we have to be careful.

More details on the sub-topics below.