Others have noticed this also (including me) and it has been reported to development.
Many users seem fine though.
Hopefully it will be fixed soon as previous 64 bit (beta) versions seemed OK.

If you want to try things, maybe try ASIO vs MME drivers (or WAS drivers) and the bit settings (16 vs 24).
To me the distortion/crackling sounds like a driver/conversion type of issue. Could be wrong.

I do know some users that have experienced it are using the same drivers in 32 and 64 bit, leading me to think the problem is in the released 64 bit version.
Shoot an email to support to let them know you are also hearing this, as it may help with prioritizing the fix.

I haven't seen any noted fixes in the updates, but it would also be worth making sure you have the latest update installed which is linked in the Sticky's at the top of this forum.

I do not work here, but the benefits are still awesome
Make your sound your own!