MHz refers to the samples per second, not the pitch. CD audio for example is 16-bit/44.1kHz. What that means is there are 16-bits of sampling (audio) taken 44,100 times per second. DSD on the other hand is 1-bit samples taken 11.2 million times per second, this is referred to as DSD256. What that translates to is a digital wave that looks a lot closer to an analog wave than a CD does. It has nothing to do with the frequency of listening in this case.

If you'd like to learn more, check this out.