Sampling at a rate of 22 kHz, or sampling up to a frequency of 22 kHz?

Up to 22kHz audio range would surely be enough for a full audio spectrum sweep at different levels, or am I missing something?

Even if it was only a rate of 22k, that would still give you a sweep range of 11kHz. I can't hear much above 16k anyway, and in a car I'm not so interested in high frequency response, more low- and mid-range.